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  • 51.
    Emanuelsson, Caroline
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Strandell, Linnea
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    "Hur gammal skulle du vara om du inte visste hur gammal du är?": En kvantitativ studie om seniorers fysiska aktivitetsvanor2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    Denna studie handlade främst om fysiska aktivitetsvanor hos seniorer och hur de upplever möjligheterna till fysisk aktivitet inom sin kommun.

     

    Syfte och frågeställningar

    Vårt syfte med studien var att undersöka hur mycket och på vilket sätt seniorer rör på sig i två olika Stockholmskommuner, samt hur de mår. Utöver detta ville vi även ta reda på om de hört talas om VillGott. 

    • Hur ser seniorernas fysiska aktivitetsvanor ut i Huddinge respektive Sollentuna?
    • Hur upplever seniorer i respektive kommuner att möjligheten till fysisk aktivitet är?
    • Har seniorerna i utvalda kommuner hört talas om projektet VillGott?

     

    Metod

    För att samla in data valdes en kvantitativ metod i form av enkät. Insamlingssätten som användes var gruppenkät och hämta-och-lämna-enkät. Enkäten delades ut till 162 seniorer på seniorträffar, seniorcentrum och PRO-aktiviteter inom de båda kommunerna. Enkätsvaren bearbetades i SPSS 19.0.

     

    Resultat

    Studiens resultat visar att 92 % av respondenterna rör på sig minst en gång i veckan och en stor del av dessa rör sig 2-3 dagar i veckan. Större delen (80 %) anser att möjligheterna till fysisk aktivitet är goda. Tre personer av 162 respondenter har hört talas om VillGott.

     

    Slutsats

    Slutsatsen är att en stor andel av seniorerna inom de båda kommunerna utövade fysisk aktivitet och detta borde innebära att möjligheterna till fysisk aktivitet är goda. Beträffande VillGott kan vi konstatera att ryktet ej har spridit sig och att det kanske skulle krävas ytterligare exponering i media eller på annat sätt om de vill att fler ska veta att de finns.

  • 52.
    Enqvist, Jonas K
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mattsson, C Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Johansson, Patrik H
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Brink-Elfegoun, Thibault
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Energy turnover during 24 hours and 6 days of adventure racing.2010In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 28, no 9, p. 947-955Article in journal (Refereed)
    Abstract [en]

    Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake ([Vdot]O(2)) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and [Vdot]O(2) were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 +/- 2,390 kcal (750 +/- 100 kcal . h(-1)) and 80,000 +/- 18,000 kcal (500 +/- 100 kcal . h(-1)) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 +/- 1,160 kcal, resulting in an energy deficit of 9,590 +/- 770 kcal. Body mass decreased in Study 1 (-2.3 +/- 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (-2.3 +/- 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.

  • 53. Eriksson Crommert, Martin
    et al.
    Halvorsen, Kjartan
    Ekblom, Maria M
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes.2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 11, article id e0141777Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.

  • 54. Essén-Gustavsson, Birgitta
    et al.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Effect of exercise on concentrations of free amino acids in pools of type I and type II fibres in human muscle with reduced glycogen stores.2002In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 174, no 3, p. 275-81Article in journal (Refereed)
    Abstract [en]

    A few animal studies have shown that some amino acid concentrations vary between different muscle fibre types. In the present study, amino acid concentrations were measured in separate pools of different fibre types in human skeletal muscle, with reduced glycogen stores, before and after sustained exercise. Five subjects exercised at a submaximal work rate for 60 min and then at a maximal rate for 20 min. Biopsy samples were taken from the vastus lateralis muscle before and after exercise; they were freeze-dried and individual fibres were dissected out. Fragments of these fibres were stained for myosin-adenosine triphosphatase (ATPase) and identified as type I or type II fibres. The concentrations of free amino acids were measured by high performance liquid chromatography (HPLC) in perchloric acid (PCA) extracts containing pools of either type of fibre. After exercise, glycogen was decreased in type I fibres (53%) and in four subjects also in type II fibres. The concentrations of most amino acids were similar in the two fibre types before exercise, but the glutamate, aspartate and arginine levels were 10% higher in type II than in type I fibres. After exercise, the glutamate concentration was decreased by 45% in both fibre types and the branched-chain amino acids (BCAA) were decreased in type II fibres (14%). Exercise caused an increase by 25-30% in tyrosine concentration in both type I and type II fibres. The results show that amino acids can be measured in pools of fibre fragments and suggest that amino acid metabolism play an important role in both type I and type II fibres during exercise.

  • 55.
    Faager, Gun
    et al.
    Medicin/Thoraxsektionen, sjukgymnastikkliniken Karolinska universitetssjukhuset Solna.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Sköld, Carl Magnus
    Rundgren, Siw
    Tollbäck, Anna
    Jakobsson, Per
    Creatine supplementation and physical training in patients with COPD: a double blind, placebo-controlled study.2006In: International journal of chronic obstructive pulmonary disease, ISSN 1176-9106, Vol. 1, no 4, p. 445-53Article in journal (Refereed)
    Abstract [en]

    STUDY OBJECTIVES: Patients with chronic obstructive pulmonary disease (COPD) have low exercise capacity and low content of high energetic phosphates in their skeletal muscles. The aim of the present study was to investigate whether creatine supplementation together with exercise training may increase physical performance compared with exercise training in patients with COPD. DESIGN: In a randomized, double-blind, placebo-controlled study, 23 patients with COPD (forced expiratory volume in one second [FEV1] < 70% of predicted) were randomized to oral creatine (n = 13) or placebo (n = 10) supplementation during an 8-week rehabilitation programme including exercise training. Physical performance was assessed by Endurance Shuttle Walking Test (ESWT), dyspnea and leg fatigue with Borg CR- 10, quality of life with St George's Respiratory Questionnaire (SGRQ). In addition, lung function test, artery blood gases, grip strength test, muscle strength and fatigue in knee extensors were measured. RESULTS: COPD patients receiving creatine supplementation increased their average walking time by 61% (ESWT) (p < 0.05) after the training period compared with 48% (p = 0.07) in the placebo group. Rated dyspnea directly after the ESWT decreased significantly from 7 to 5 (p < 0.05) in the creatine group. However, the difference between the groups was not statistically significant neither in walking time nor in rated dyspnea. Creatine supplementation did not increase the health related quality of life, lung function, artery blood gases, grip strength and knee extensor strength/fatigue. CONCLUSIONS: Oral creatine supplementation in combination with exercise training showed no significant improvement in physical performance, measured as ESWT, in patients with COPD compared with exercise training alone.

  • 56.
    Fernström, Maria
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Tonkonogi, Michail
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Shabalina, Irina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Rozhdestvenskaya, Z
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Enqvist, Jonas K
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Reduced efficiency, but increased fat oxidation, in mitochondria from human skeletal muscle after 24-h ultraendurance exercise.2007In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 102, no 5, p. 1844-1849Article in journal (Refereed)
    Abstract [en]

    The hypothesis that ultraendurance exercise influences muscle mitochondrial function has been investigated. Athletes in ultraendurance performance performed running, kayaking, and cycling at 60% of their peak O(2) consumption for 24 h. Muscle biopsies were taken preexercise (Pre-Ex), postexercise (Post-Ex), and after 28 h of recovery (Rec). Respiration was analyzed in isolated mitochondria during state 3 (coupled to ATP synthesis) and state 4 (noncoupled respiration), with fatty acids alone [palmitoyl carnitine (PC)] or together with pyruvate (Pyr). Electron transport chain activity was measured with NADH in permeabilized mitochondria. State 3 respiration with PC increased Post-Ex by 39 and 41% (P < 0.05) when related to mitochondrial protein and to electron transport chain activity, respectively. State 3 respiration with Pyr was not changed (P > 0.05). State 4 respiration with PC increased Post-Ex but was lower than Pre-Ex at Rec (P < 0.05 vs. Pre-Ex). Mitochondrial efficiency [amount of added ADP divided by oxygen consumed during state 3 (P/O ratio)] decreased Post-Ex by 9 and 6% (P < 0.05) with PC and PC + Pyr, respectively. P/O ratio remained reduced at Rec. Muscle uncoupling protein 3, measured with Western blotting, was not changed Post-Ex but tended to decrease at Rec (P = 0.07 vs. Pre-Ex). In conclusion, extreme endurance exercise decreases mitochondrial efficiency. This will increase oxygen demand and may partly explain the observed elevation in whole body oxygen consumption during standardized exercise (+13%). The increased mitochondrial capacity for PC oxidation indicates plasticity in substrate oxidation at the mitochondrial level, which may be of advantage during prolonged exercise.

  • 57.
    Fernström, Maria
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Shabalina, Irina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Bakkman, Linda
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Tonkonogi, Michail
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Enqvist, Jonas
    Swedish School of Sport and Health Sciences, GIH.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Skeletal muscle mitochondrial function and ROS production in response to extreme endurance exercise in athletes.2006In: 14 European bioenergetic conference, Moscow, Russia, 22-27 July, 2006, 2006Conference paper (Other academic)
    Abstract [en]

    Although it is well known that endurance exercise induces oxidative stress (1) there is no evidence of deteriorated mitochondrial function after 1-2 hours intensive exercise (2). However, the effects of extreme endurance exercise on mitochondrial function and mitochondrial ROS production have not been investigated previously. Nine healthy well-trained men (age 27.1 ± 0.87 (mean ± SE), BMI 24.2 ± 0.64 and VO2 peak 62.5 ± 1.78 ml/kg. min) performed 24 hours exercise, consisting of equal parts running, cycling and paddling. Muscle biopsies were taken from vastus lateralis pre-exercise (PreEx), immediately post-exercise (PostEx) and after 28 hours of recovery (PostEx-28). Mitochondria were isolated and mitochondrial respiration was analyzed with palmitoyl-carnitine (PC) and pyruvate (Pyr). Mitochondrial H2O2 release was measured with the Amplex Red-horseradish peroxide method. The reaction was initiated by addition of succinate with following addition of antimycin A (reversed electron flow). UCP3 protein expression, evaluated with western blot technique, was not changed by exercise. Both state 3 (Pyr and PC) and state 4 (PC) rates of oxygen consumption (estimated per maximal ETC-activity) were increased PostEx (+29%, +11% and +18%). State 3 remained elevated PostEx-28, whereas state 4 (Pyr) decreased below that at PreEx (-18%). Mitochondrial efficiency (P/O) decreased PostEx (Pyr -8.9%, PC -6.1%) and remained reduced PostEx-28. The relative substrate oxidation (state 3 PC/Pyr) increased after exercise PreEx: (0.71 ± 0.06 vs. PostEx (0.90 ±0.04) and (0.77 ±0.06) PostEx-28. Mitochondrial H2O2 release (succinate) increased dramatically after exercise (+189 ± 64%). Treatment with Antimycin A resulted in a twofold-increased rate of mitochondrial H2O2 release PreEx but a decreased rate in PostEx samples. The exercise-induced changes in mitochondrial ROS production was totally abolished PostEx-28. In conclusion extreme endurance exercise decreases mitochondrial efficiency and increases mitochondrial ROS production. Both of these changes would increase the oxygen demand during exercise. Relative fatty acid oxidation as measured in isolated mitochondria increased after exercise indicating that the capacity to oxidize fat is improved during prolonged exercise.

    1. Mastaloudis, A., S.W. Leonard, and M.G. Traber, Oxidative stress in athletes during extreme endurance exercise. Free Radic Biol Med, 2001. 31(7): p. 911-22.

    2. Tonkonogi, M., et al., Mitochondrial function and antioxidative defence in human muscle: effects of endurance training and oxidative stress. J Physiol, 2000. 528 Pt 2: p. 379-88.

  • 58.
    Fernström, Maria
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Tonkonogi, Michail
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Effects of acute and chronic endurance exercise on mitochondrial uncoupling in human skeletal muscle.2004In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 554, p. 755-763Article in journal (Refereed)
    Abstract [en]

    Mitochondrial proteins such as uncoupling protein 3 (UCP3) and adenine nucleotide translocase (ANT) may mediate back-leakage of protons and serve as uncouplers of oxidative phosphorylation. We hypothesized that UCP3 and ANT increase after prolonged exercise and/or endurance training, resulting in increased uncoupled respiration (UCR). Subjects were investigated with muscle biopsies before and after acute exercise (75 min of cycling at 70% of .VO2peak) or 6 weeks endurance training. Mitochondria were isolated and respiration measured in the absence (UCR or state 4) and presence of ADP (coupled respiration or state 3). Protein expression of UCP3 and ANT was measured with Western blotting. After endurance training, .VO2peak, citrate synthase activity (CS), state 3 respiration and ANT increased by 24, 47, 40 and 95%, respectively (all P < 0.05), whereas UCP3 remained unchanged. When expressed per unit of CS (a marker of mitochondrial volume) UCP3 and UCR decreased by 54% and 18%(P < 0.05). CS increased by 43% after acute exercise and remained elevated after 3 h of recovery (P < 0.05), whereas the other muscle parameters remained unchanged. An intriguing finding was that acute exercise reversibly enhanced the capacity of mitochondria to accumulate Ca2+(P < 0.05) before opening of permeability transition pores. In conclusion, UCP3 protein and UCR decrease after endurance training when related to mitochondrial volume. These changes may prevent excessive basal thermogenesis. Acute exercise enhances mitochondrial resistance to Ca2+ overload but does not influence UCR or protein expression of UCP3 and ANT. The increased Ca2+ resistance may prevent mitochondrial degradation and the mechanism needs to be further explored.

  • 59.
    Flockhart, Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Validation of modified D-max method for calculating individual anaerobic threshold in well trained male cyclists2015Conference paper (Refereed)
    Abstract [en]

    Introduction

    To predict endurance performance and evaluate adaption to training in endurance athletes a laboratory test for retrieving the anaerobic lactate threshold is often used. The maximal rate of oxidative metabolism that can be sustained during prolonged exercise indicates preserved homeostasis and thereby sets the upper limit for long term endurance. Exercise intensities above the anaerobic threshold require an additional input from anaerobic energy sources resulting in blood lactate accumulation and reduced time to fatigue. The threshold is therefore a reliable and powerful predictor of performance in aerobic exercise lasting approximately 40-60 min. The work rate that elicits a blood lactate of 4 mmol/l (e.g. LT4) is widely used to determine the threshold, but by using a fixed lactate concentration, flexibility to account for inter- and intra-individual differences in aerobic and anaerobic metabolism is lost. Our hypothesis was that our modified D-max method (D-maxmod) would provide a more accurate performance related value by calculating the individual anaerobic threshold (IAT).

    Methods

    20 males cyclists age 36 ± 5 years, weight 79.7 ± 5.8 kg, VO2max 4.4 ± 0.4 l/min performed an incremental test on a cycle ergometer for calculation of LT (D-maxmod, and LT4) at two occasions separated by 8 weeks. The test consisted of 5 minutes long stages separated by 1 min of rest were lactate was sampled. The increase in work rate was 30 W/stage starting at 100 W and ended above LT4. Short after, an incremental test to fatigue (start at LT4 power, increase 20 W/min) was performed for assessment of VO2max, calculation of maximal aerobic power (MAP) and maximal power achieved in the test (Wmax). On a separate day a 40 minutes time-trial (TT40) was performed for assessment of aerobic endurance performance. IAT D-maxmod was defined as the derivate to the exponential curve created from exponentially lactate increase, including maximal lactate concentration plotted at MAP. The increase in lactate relative to power was defined as the increase in blood lactate from the point where the exponential curve crossed the lactate baseline (See also Cheng et al. 1992 and Zhou & Weston 1997).

    Results

    IAT D-maxmod was calculated to 5.0 ± 0.8 mmol/l. Both D-maxmod and LT4 were highly significantly correlated with both TT40 and Wmax. Coefficients of determination were higher for D-maxmod compared to LT4 for both TT40 (r2 = 0.78 vs 0.69) and Wmax (r2 = 0.89 vs 0.64).

    Conclusion

    The calculated D-maxmod correlated better with performance than LT4 for parameters highly linked to performance in road- and mountain bike competitions.

    References

    Cheng B, Kuipers H, Snyder AC, et al. (1992). Int. J Sports Med. 13:518-22

    Zhou S, Weston SB (1997). Physiol. Meas. 18: 145

  • 60.
    Flockhart, Mikael
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mattsson, Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Fysiologisk analys av utbildningsmomentet "Markstrid grundkurs (GK) 1, Fjällmarsch"2014Report (Other academic)
    Abstract [sv]

    Denna observationsstudie av militär grundutbildning för kadetter visar mycket tydligt att förflyttning i fjällmiljö leder till stort energiunderskott, till viss del beroende på ökade energiutgifter i och med bärande av utrustning, men framför beroende på otillräckligt energiintag.

    Den genomsnittliga energiförbrukningen över övningens 100 timmarna och ca 78 km förflyttning var ca 260 kcal/h, medan energiintaget endast 135 kcal/h. Även om en typ av rations (mjukkonserv) gav i genomsnitt högre energiintag än två rations av frystorkat blev det genomsnittliga energiunderskottet för samtliga rations nästan 50 %.

    Mätningarna visade stora variationer mellan olika deltagare vilket dock endast delvis kan förklaras med tekniken av att bära tungt.

    Skjutprov (precision) visade att stridsvärdet påverkats negativt, genom en klart försämrad träffbild efter övningen. De fysiologiska testerna visar ökad hjärtfrekvens och upplevd ansträngning på submaximala belastningar, medan de maximala nivåerna av de fysiologiska kapaciteterna kondition, muskelstyrka i hand och ben i stort sett var oförändrade.

    Kommande undersökningar på motsvarande övningar bör inriktas på interventionsstudier på fördelning av utrustningsvikter, samt hur kostintaget bör förbättras för att nå ökat energiintag.

    På längre sikt bör träningsmodeller för att förbättra förmågan att bära tung utrustning utvärderas.

  • 61.
    Frank, Per
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Katz, Abram
    Karolinska Institutet.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Acute exercise reverses starvation-mediated insulin resistance in humans.2013In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 304, no 4, p. E436-43Article in journal (Refereed)
    Abstract [en]

    Within 2-3 days of starvation, pronounced insulin resistance develops, possibly mediated by increased lipid load. Here, we show that one exercise bout increases mitochondrial fatty acid (FA) oxidation and reverses starvation-induced insulin resistance. Nine healthy subjects underwent 75-h starvation on two occasions: with no exercise (NE) or with one exercise session at the end of the starvation period (EX). Muscle biopsies were analyzed for mitochondrial function, contents of glycogen, and phosphorylation of regulatory proteins. Glucose tolerance and insulin sensitivity, measured with an intravenous glucose tolerance test (IVGTT), were impaired after starvation, but in EX the response was attenuated or abolished. Glycogen stores were reduced, and plasma FA was increased in both conditions, with a more pronounced effect in EX. After starvation, mitochondrial respiration decreased with complex I substrate (NE and EX), but in EX there was an increased respiration with complex I + II substrate. EX altered regulatory proteins associated with increases in glucose disposal (decreased phosphorylation of glycogen synthase), glucose transport (increased phosphorylation of Akt substrate of 160 kDa), and FA oxidation (increased phosphorylation of acetyl-CoA carboxylase). In conclusion, exercise reversed starvation-induced insulin resistance and was accompanied by reduced glycogen stores, increased lipid oxidation capacity, and activation of signaling proteins involved in glucose transport and FA metabolism.

  • 62. Fridén, Jan
    et al.
    Seger, Jan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Implementation of periodic acid-thiosemicarbazide-silver proteinate staining for ultrastructural assessment of muscle glycogen utilization during exercise1985In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, no 242, p. 229-232Article in journal (Refereed)
    Abstract [en]

    Distribution of glycogen particles in semithin and ultrathin sections of biopsy samples from human muscles subjected to either short- or long-term running were investigated using PAS and Periodic Acid-ThioSemiCarbazide-Silver Proteinate (PA-TSC-SP) staining methods. Glycogen particles were predominantly found immediately under the sarcolemma or aligned along the myofibrillar I-band. After long-term exhaustive exercise type-1 fibers with a few or no glycogen particles in the core of the fibers were frequently observed. The subsarcolemmal glycogen stores of these "depleted" type-1 fibers were about three times as large as after exhaustive short-time exercise. Another indication of utilization of subsarcolemmal glycogen stores during anaerobic exercise was that many particles displayed a pale, rudimentary shape. This observation suggests fragmental metabolization of glycogen. Thus, depending on type of exercise and type of fiber differential and sequential glycogen utilization patterns can be observed

  • 63. Fridén, Jan
    et al.
    Seger, Jan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Sublethal muscle fibre injuries after high-tension anaerobic exercise1988In: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, no 57, p. 360-368Article in journal (Refereed)
    Abstract [en]

    The vastus lateralis muscles of eleven male elite sprinters (17-28 years) were investigated in order to examine the impact of high tension anaerobic muscular work on muscle fibre fine structure. In an attempt to reproduce the training regimen six subjects ran 20 repetitions of 25 s on a treadmill with 2 min 35 s in between, at a speed corresponding to 86% of their personal best 200 m time. PAS-stained sections of biopsies taken approximately 2 h after training generally indicated glycogen depletion in type 1 and type 2B fibres. At the light microscopic level, no signs of inflammation or fibre rupture were observed. However, at the ultrastructural level, frequent abnormalities of the contractile material and the cytoplasmic organelles were detected. Z-band streaming, autophagic vacuoles and abnormal mitochondria were the most conspicuous observations. Control specimens from sprinters who did not perform the acute exercise routine also displayed structural deviations, although to a lesser degree. It is hypothesized that during sprint training the leg musculature is put under great mechanical and metabolic stress which causes the degenerative response reported here.

  • 64. Fridén, Jan
    et al.
    Seger, Jan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Topographical localization of muscle glycogen: an ultrahistochemical study in the human vastus lateralis1989In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 135, p. 381-391Article in journal (Refereed)
    Abstract [en]

    The fine structural pattern of glycogen storage in resting and sprint-exercised human vastus lateralis muscle fibres of different types was analysed using ultrahistochemical methods. Three male subjects (31-36 years) performed 60 consecutive, supramaximal bouts of bicycle exercise, each starting every 1 min and having a duration of 8 s (including approximately 3 s of acceleration). The load was estimated to correspond to 200% of VO2-max. Five other subjects (22-27 years) constituted controls. Ultrathin sections stained with periodic acid-thiosemicarbazide-silver proteinate (PA-TSC-SP) clearly revealed a compartmental distribution of glycogen. Glycogen is stored at five topographically, and probably also functionally, different locations. They are the subsarcolemmal, intermyofibrillar, para-Z-disc, N2-line, and H-zone spaces. During the exercise, glycogen from the N2-line and para-Z-disc locations is preferentially utilized. Serial sections stained with uranyl acetate and lead citrate demonstrated that glycogen stores of the type 2 fibres were more depleted than those of type 1 fibres. The implications of the differential intracellular glycogen storage are discussed

  • 65.
    Gago, Paulo
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Tarassova, Olga
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Ekblom, Maria M
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Post activation potentiation can be induced without impairing tendon stiffness.2014In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 114, no 11, p. 2299-2308Article in journal (Refereed)
    Abstract [en]

    PURPOSE: This study aimed to investigate conditioning effects from a single 6-s plantar flexion maximal voluntary isometric contraction (MVIC) on Achilles tendon stiffness (ATS) and twitch properties of the triceps surae in athletes.

    METHODS: Peak twitch (PT), rate of torque development (RTD), rising time (RT10-90%) and half relaxation time (HRT) were measured from supramaximal twitches evoked in the plantar flexors of 10 highly trained athletes. Twitches were evoked before and at seven occasions during 10 min of recovery after a 6-s MVIC. In a second session, but at identical post-conditioning time points, ATS was measured at 30 and 50 % of MVIC (ATS30% and ATS50%) using an ultrasonography-based method.

    RESULTS: The magnitude and duration of the conditioning MVIC on muscle contractile properties were in accordance with previous literature on post activation potentiation (PAP), i.e., high potentiation immediately after MVIC, with significant PAP for up to 3 min after the MVIC. While PT and RTD were significantly enhanced (by 60.6 ± 19.3 and 90.1 ± 22.5 %, respectively) and RT10-90% and HRT were reduced (by 10.1 ± 7.7 and 18.7 ± 5.6 %, respectively) after conditioning, ATS remained unaffected.

    CONCLUSIONS: Previous studies have suggested that changes in stiffness after conditioning may interfere with the enhancements in twitch contractile properties. The present study, however, provided some evidence that twitch enhancements after a standard PAP can be induced without changes in ATS. This result may suggest that athletes can use this protocol to enhance muscle contractile properties without performance deficits due to changes in ATS.

  • 66.
    Glas, Peter
    et al.
    Swedish School of Sport and Health Sciences, GIH.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Physiological requirements of elite handball – measured with a combination of local positioning system and heart rate monitoring.2017Conference paper (Refereed)
    Abstract [en]

    For all athletes, it is important to adjust training plans and competition schedule according to each individual's specific traits and situation. This is crucial in team sports, where players, despite being involved in the same sport, and even on the same team, may have very different physiological capacities and, also have completed a wide variety of work in both training and match situations. A first step towards being able to carry out individualized training is to accurately measure the amount of stress (physiological burden) for each individual. The purpose of the study was to create a comprehensive picture of the physical requirements of elite handball matches, and further investigate how the relationship between work load and physical capacity impacts performance.

    Heart rate measurements have since decades been used to quantify the relative work, and GPS measurement as a tool for objective values has been available for outdoor sports for about ten years, but GPS is not possible to use indoors. We have used a new technology with a similar system for indoor use called Local Positioning System (LPS) (Kinexon Precision Technologies, Münich, Germany) to record and analyze the players’ motion during games, and we have combined that technology with data from accelerometry, gyroscope and heart rate measurements.

    So far, 42 handball matches have been measured and analyzed, ranging from juniors (9 games U21 men's national team) to seniors, men and women, and both in Sweden’s highest league and between national teams (Women: 8 national and 7 international games; Men: 14 national and 4 international games).

    A first "result" is that the categorization of motion patterns need to be adapted to each sport. For example, some moves that should be counted as accelerations in handball are not recognized by the system, simply because it has been adapted to the pattern of motion on the much larger soccer field. This is similarly important to realize when comparing results for handball’s physiological requirements reached using other technologies. In this presentation, we will in part discuss the future technological opportunities, and in part report descriptive results, including how fast and far the players move, as well as differences between men and women, between national and international games, and between juniors and seniors.

  • 67.
    Godhe, Manne
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Helge, Torbjörn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mattsson, C Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Physiological factors of importance for load carriageManuscript (preprint) (Other academic)
    Abstract [en]

    The energy expenditure during carrying no load, 20, 35 and 50 kg at two walking speeds, 3 and 5 km/h, was studied in 36 healthy participants, 19 men (30 ± 6 yrs, 82.5 ± 7.0 kg) and 17 women (29 ± 6 yrs, 66.1 ± 8.9 kg). Anthropometric data, leg muscle strength as well as trunk muscle endurance and muscle fibre distribution of the thigh were also obtained. To load the participant a standard backpack filled with extra weight according to the carrying weight tested was used. Extra Load Index (ELI), the oxygen uptake (VO2) during total load over no-load-exercise, was used as a proxy for load carrying ability. In addition to analyzing factors of importance for the ELI values, we also conducted mediator analyzes using sex and long term carrying experience as causal variables for ELI as the outcome value. For the lowest load (20 kg), ELI20, was correlated with body mass but no other factors. Walking at 5 km/h body mass, body height, leg muscle strength and absolute VO2max were correlated to ELI35 and ELI50, but relative VO2max, trunk muscle endurance and leg muscle fibre distribution were not. Sex as causal factor was evaluated in a mediator analyses with ELI50 as outcome. ELI50 at 5 km/h differed between the sexes. The limit for acceptable body load, 40% of VO2max (according to Astrand, 1967), was nearly reached for women carrying 35 kg (39%) and surpassed at 50 kg at 3 km/h, and for men carrying 50 kg at 5 km/h. This difference was only mediated by difference in body mass. Neither muscle fibre distribution, leg muscle strength, trunk muscle endurance and body height nor did absolute or relative VO2max explain the difference. Participants with long term experience of heavy load carrying had significant lower ELI20 and ELI50 values than those with minor or non-experience, but none of the above studied factors could explain this difference. The study showed that body mass and experience of carrying heavy loads are important factors for the ability to carry heavy loads.

  • 68.
    Gray, Stuart R
    et al.
    Strathclyde inst of pharmacy and biomedical sciences, university of strathclyde, Glasgow UK.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ferguson, Richard A
    ATP and phosphocreatine utilization in single human muscle fibres during the development of maximal power output at elevated muscle temperatures.2008In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 26, no 7, p. 701-7Article in journal (Refereed)
    Abstract [en]

    In this study, we examined the effect of muscle temperature (Tm) on adenosine triphosphate (ATP) and phosphocreatine utilization in single muscle fibres during the development of maximal power output in humans. Six male participants performed a 6-s maximal sprint on a friction-braked cycle ergometer under both normal (Tm = 34.3 degrees C, s = 0.6) and elevated (T(m) = 37.3 degrees C, s = 0.2) muscle temperature conditions. During the elevated condition, muscle temperature of the legs was raised, passively, by hot water immersion followed by wrapping in electrically heated blankets. Muscle biopsies were taken from the vastus lateralis before and immediately after exercise. Freeze-dried single fibres were dissected, characterized according to myosin heavy chain composition, and analysed for ATP and phosphocreatine content. Single fibres were classified as: type I, IIA, IIAX25 (1 - 25% IIX isoform), IIAX50 (26 - 50% IIX), IIAX75 (51 - 75% IIX), or IIAX100 (76 - 100% IIX). Maximal power output and pedal rate were both greater (P < 0.05) during the elevated condition by 258 W (s = 110) and 22 rev . min(-1) (s = 6), respectively. In both conditions, phosphocreatine content decreased significantly in all fibre types, with a greater decrease during the elevated condition in type IIA fibres (P < 0.01). Adenosine triphosphate content was also reduced to a greater (P < 0.01) extent in type IIA fibres during the elevated condition. The results of the present study indicate that after passive elevation of muscle temperature, there was a greater decrease in ATP and phosphocreatine content in type IIA fibres than in the normal trial, which contributed to the higher maximal power output.

  • 69.
    Helge, Torbjörn
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Godhe, Manne
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Mattsson, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Att bära tungt: en fysiologisk analys2015Report (Other academic)
    Abstract [sv]

    Nitton manliga vältränade försökspersoner, 9 st med vana att bära tungt och 10 st utan sådan vana, genomförde gång på mjukt underlag i hastigheterna 3 och 5 km/tim med bärvikter i ryggsäck på 20, 35 och 50 kg.

    Energiomsättningen ökade i genomsnitt lika mycket med ökad hastighet som med ökad bärvikt. Mjukt underlag, indikerande gång i lätt terräng, ökade energiomsättningen under både hastigheterna med c:a 20 %, jämfört med hårtunderlag (löpband). Den individuella variationen vid en given bärvikt och hastighet är mycket stor. Beroende på bärvikt och hastighet kan energiomsättningen variera med 100%.  Dessa stora variationer i energiomsättning bör uppmärksammas vid beräkning av energitilldelning via kosten vid längre militära operationer.

    Energiomsättningen vid tyngsta belastningen – 50 kilo bärvikt och hastigheten 5 km/tim – belastade försökspersonerna på i genomsnitt 44 % av maximal syreupptagningsförmåga. I individuella fall var belastningen 60%. Dessa höga belastningar är oacceptabelt höga för transporter under längre tid och kan vara en orsak till belastningsskador.

    Förmågan att bära tungt sammanfaller med ökad kroppsstorlek – både längd och vikt – ålder, maximal syreupptagningsförmåga mätt i L/min men inte i ml/min och kg kroppsvikt, benmuskelstyrka men inte bålmuskelstyrka samt andelen muskelfibrer i lårmuskeln av typ 1. Flera men inte alla av dessa förmågor kan säkert till viss del tränas upp. Bärförmåga för mindre vikter, högst 35 kg, sammanfaller inte med några av ovanstående faktorer, bortsett från ålder. Således, för tyngre bärvikter vid förflyttningar bör selektion av soldater ske enligt de uppmätta parametrarna, medan vad gäller lättare vikter föreligger inte samma selektionkriterier.

    En slutsats från resultaten av denna undersökning är den ursprungliga uttagningen till tunga arbetsuppgifter inom försvaret bör genomföras med tunga arbetsbelastningar, motsvarande de i denna undersökning. Avsikten i fortsättningen av denna undersökningsserie är att fastställa ny testmetodik och procedur för denna selektion samt genomföra tester på kvinnor.

  • 70. Hendo, Gina
    et al.
    Jakobsson, Madeleine
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekblom Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Flockhart, Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Slutövning GMU: "Aldrig ge upp", Amf1, Berga örlogsbas: Muskelfysiologiska resultat2014Report (Other academic)
    Abstract [sv]

    Energistatus, muskelfysiologiska data och fysiskt stridsvärde studerades före och efter en 8 dygn långa grundmilitär slutövning (GMU) vid AMF-1 Berga Örlogsskolor i månadsskiftet oktober november 2013.

    Totalt deltog 105 soldater i övningen, fördelat på 3 plutoner om vardera 35 soldater. En subgrupp på 24 soldater (8 kvinnor) bestående av 8 soldater från vardera pluton studerades mer ingående.

    Medelhjärtfrekvensen för de 6 soldater (2 kvinnor) som hade i stort sett kompletta mätningar från den 187 timmar långa övningen, inklusive viloperioder, var 88 ± 7 slag/minut. Utifrån hjärtfrekvensdata beräknades den totala energiomsättningen till i genomsnitt 44 000 ± 6 600 kcal, vilket motsvarar 5 600 ± 840 kcal per dygn och 235 ± 35 kcal/tim. Total energiförbrukning var i genomsnitt 39 000 kcal för kvinnorna och 46 500 kcal för männen. I övrigt noterades inte några betydande skillnader mellan kvinnor och män. Däremot var det stora individuella variationer i energiutgift, vilka till ca hälften berodde på skillnader i kroppsvikt. Med hänsyn till kroppsvikt och buren vikt var energiförbrukningen ca 3,1 ± 0,23 kcal per timme per kg totalvikt. Den individuella variationen beror på skillnad i buren vikt, på olika uppgifter och på individuella fysiologiska skillnader.

    Utifrån beräknat energiintag blev det totala energiunderskottet under övningen 12 000-15 000 kcal, vilket är ca 1 500-2 000 kcal per dygn. Viktminskningen under övningen var 2,9 kg för kvinnor och 3,7 kg för män. Denna viktminskning på >4 % leder troligen till försämrad uthållighetsförmåga.

    Den maximala muskelstyrkan i armar och ben var i stort sett oförändrade efter övningen, liksom den beräknade maximala syreupptagningsförmågan. Däremot upplevdes ett lågintensivt cykelarbete som betydligt tyngre efter övningen. Muskeluthållighet mättes inte i denna studie.

    Ett skjutprov om 5 skott i liggande på 100 m mot en tredjedelsfigur visade 64 deltagande soldater på en försämrad träffprocent från 90,5% före till 79,4 % efter övningen. Alla soldater hade minst en träff före medan 6 soldater hade alla bom efter övningen.

    Slutsatsen från studien är att GMU-övningen resulterade i ett stort energiunderskott. Stridsvärdet, bedömt från skjutprovet var klart försämrat. Maximala fysiologiska parametrar var i stort sett oförändrade, medan skattad ansträngning och därmed uthållighetsförmåga, försämrades.

  • 71. Hey-Mogensen, M
    et al.
    Højlund, K
    Vind, B F
    Wang, Li
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Dela, F
    Beck-Nielsen, H
    Fernström, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Effect of physical training on mitochondrial respiration and reactive oxygen species release in skeletal muscle in patients with obesity and type 2 diabetes.2010In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 53, no 9, p. 1976-85Article in journal (Refereed)
    Abstract [en]

    AIM/HYPOTHESIS: Studies have suggested a link between insulin resistance and mitochondrial dysfunction in skeletal muscles. Our primary aim was to investigate the effect of aerobic training on mitochondrial respiration and mitochondrial reactive oxygen species (ROS) release in skeletal muscle of obese participants with and without type 2 diabetes. METHODS: Type 2 diabetic men (n = 13) and control (n = 14) participants matched for age, BMI and physical activity completed 10 weeks of aerobic training. Pre- and post-training muscle biopsies were obtained before a euglycaemic-hyperinsulinaemic clamp and used for measurement of respiratory function and ROS release in isolated mitochondria. RESULTS: Training significantly increased insulin sensitivity, maximal oxygen consumption and muscle mitochondrial respiration with no difference between groups. When expressed in relation to a marker of mitochondrial density (intrinsic mitochondrial respiration), training resulted in increased mitochondrial ADP-stimulated respiration (with NADH-generating substrates) and decreased respiration without ADP. Intrinsic mitochondrial respiration was not different between groups despite lower insulin sensitivity in type 2 diabetic participants. Mitochondrial ROS release tended to be higher in participants with type 2 diabetes. CONCLUSIONS/INTERPRETATION: Aerobic training improves muscle respiration and intrinsic mitochondrial respiration in untrained obese participants with and without type 2 diabetes. These adaptations demonstrate an increased metabolic fitness, but do not seem to be directly related to training-induced changes in insulin sensitivity.

  • 72. Hodges, Paul W
    et al.
    Cresswell, Andrew G
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Thorstensson, Alf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Intra-abdominal pressure response to multidirectional support-surface translation.2004In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 20, no 2, p. 163-70Article in journal (Refereed)
    Abstract [en]

    A complex response of the trunk muscles occurs to restore equilibrium in response to movement of the support surface. Intra-abdominal pressure (IAP) is considered to contribute to control of the trunk. This study investigated the contribution of IAP to the postural response to multidirection support-surface translation. IAP was recorded with a thin-film pressure transducer inserted via the nose into the stomach and trunk motion was recorded with an optoelectronic system with markers over the spinous process of L1. A pattern of trunk movement was recorded in response to the support-surface translations that was consistent with a 'hip' strategy of postural control. The trunk moved in a manner appropriate to move the centre of gravity over the new base of support. IAP was increased with movement in each direction, but varied in timing and amplitude between translation directions. In general, the IAP was greater with translations in the sagittal plane compared to the frontal plane and was initiated earlier for translations in the backward direction. These data indicate that IAP contributes to the postural response associated with support-surface translation and suggest that this is consistent with stiffening the spine.

  • 73.
    Holm Glaas, Nanna
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Helge, Torbjörn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Effekter vid känd, okänd och oväntad arbetstid.: Mentala färdigheters inflytande på fysiologiska och upplevelsebaserade variabler vid uthållighetsarbete.2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syfte och frågeställningar: Syftet i den här studien har varit att undersöka hur fysiologiska och upplevelsebaserade variabler skiljer sig vid känd, okänd och oväntad arbetstid samt i förhållande till mentala färdigheter. För att uppnå syftet undersöktes följande frågor. Hur påverkas fysiologiska och upplevelsebaserade variabler vid känd, okänd och oväntad arbetstid? Vilket samband finns det mellan mentala färdigheter och de fysiologiska respektive upplevelsebaserade variablerna?

    Metod: Avsikten är att upprepa tidigare studier men med nya parametrar. Testpersonerna var uthållighetstränade (57,1 ml/kg/min ±3,7SD) män med en medelålder på 37 år (±3,8SD). Vid tre olika testtillfällen utförde testpersonerna (n=7) tre olika test. Vid alla testtillfällen sprang testpersonerna på löpband i 20 minuter med en hastighet som motsvarade 80 % av maximalt syreupptag. Vid test A fick testpersonerna veta att de skulle springa i 20 minuter. Vid test B fick testpersonerna veta att de skulle springa i 10 minuter, men i den tionde minuten fick testpersonerna veta att de skulle springa ytterligare10 minuter. Vid test C fick testpersonerna ingen information om hur lång tid de skulle springa, men i den tjugonde minuten fick testpersonerna veta att testet avslutades efter totalt 20 minuter.

    Resultat: Inga signifikanta skillnader i de fysiologiska variablerna mellan test A, B och C har kunnat fastställdes. Det finns dock en tendens att syreupptaget var lägre i test B än test A och C (p<0,10). Testresultaten visar att syreupptaget sjönk mellan minut 19 och 20 i test C. De upplevelsebaserade variablerna visade inte heller på signifikanta skillnader mellan olika tester, men uppskattad ansträngning verkade vara lägre i intervallet minut 14-19 i test B jämfört med test A och C, samt att syreupptaget också här sjönk för test C mellan minut 19 och 20. Sambanden mellan de fysiologiska samt upplevelsebaserade variablerna och de mentala färdigheterna resulterade i ett signifikant lägre syreupptag (p<0,05) i test B i förhållande till test C. Vid hög self-efficacy och högt mental toughness poäng, samt ett mer stabilt känslomässigt förlopp vid hög poäng på cognitive reappraisal. Testpersonernas användning av self-talk verkade vara test specifik då mängden positivt self-talk ökade från test A till B till C oavsett viken ordning testerna utfördes.

    Slutsats: Studien visar motstridiga resultat jämfört med tidigare refererade studier. Det finns ett samband mellan de fysiologiska och upplevelsebaserade variablerna, typ av test och mentala färdigheter. Sambandet är dock otydligt och bör undersökas noggrannare.

  • 74.
    Holmlund, Tobias
    et al.
    Karolinska institutet.
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Franzén, E
    Karolinska institutet.
    Hultling, C
    Karolinska institutet.
    Wikmar, L Nilsson
    Karolinska institutet.
    Wahman, K
    Karolinska institutet.
    Energy expenditure in people with motor-complete paraplegia.2017In: Spinal Cord, ISSN 1362-4393, E-ISSN 1476-5624, Vol. 55, no 8, p. 774-781Article in journal (Refereed)
    Abstract [en]

    STUDY DESIGN: The present descriptive clinical and laboratory study is cross-sectional in design.

    OBJECTIVES: The primary aim is to describe and compare resting energy expenditure (REE) and energy expenditure (EE) during different standardized sedentary, non-exercise and exercise activities in people with motor-complete paraplegia (Th7 to Th12.). A secondary aim was to compare men and women.

    METHODS: Thirty-eight adults (10 women) with SCI, T7-T12 AIS A-B, were recruited. All the data were collected through indirect calorimetry. REE was measured in supine for 30 min after 8 h of overnight fasting. Activity energy expenditure (AEE) for activities was measured for seven minutes during sedentary, non-exercise physical activity (NEPA) and exercise activities.

    RESULTS: AEE increased four to eight times when engaging in NEPA compared to that in sedentary activities. Men had significantly higher resting oxygen uptake compared to women, 0.19 vs 0.15 l min(-1) (P=0.005), REE per 24 h, 1286 vs 1030 kcal (P=0.003) and EE during weight-bearing activities. However, these became nonsignificant after adjustment for body weight and speed of movement, with a mean resting oxygen uptake of 2.47 ml O2 per kg min(-1) for the whole group (women 2.43 and men 2.57 ml O2 kg(-1) min(-1), P=0.49).

    CONCLUSIONS: NEPA increases AEE up to eight times compared to sedentary activities. Gender differences in oxygen uptake during both rest and weight-bearing activities were diminished after adjustment for body weight. The mean resting oxygen uptake for the whole group was 2.47 ml O2 kg(-1) min(-1). These results highlight the importance, especially of NEPA, for increasing total daily EE in the target population.

  • 75.
    Irenheim, Alexander
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Peterstedt, Christopher
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Nintendo Wii vs. Sony Playstation 2: En mätning av skillnad i energiutgift hos användaren av två olika typer av tv-spelskonsoler2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpStudent thesis
    Abstract [sv]

    Syfte och frågeställningar

    Syftet med denna studie är att undersöka om det föreligger en signifikant skillnad i energiutgift vid spelande på den nya generationens spelkonsol, Nintendo Wii (Wii), jämfört med en traditionell spelkonsol, Sony Playstation 2 (PS2). De frågeställningar studien utgick ifrån var;

    Föreligger det, konsolerna emellan, en skillnad avseende energiutgift vid spelande?

    Hur skulle en eventuell skillnad i energiutgift kunna påverka en användares kroppsvikt?

    Vilka andra fysiska aktiviteter kan tv-spelande jämföras med, avseende energiutgift?

    Metod

    Testpersonerna, 13 män och 5 kvinnor, testades med avseende på O2-förbrukning samt CO2-produktion på två spel per konsol. Spelen som testades var ”Wii Tennis”, ”Next Generation Tennis” (PS2), ”Wii Boxing” samt ”Knockout Kings 2002” (PS2). Utandningsluften samlades in kontinuerligt under spel enligt Douglas Bag-metodik. Varannan försöksperson utförde testen i omvänd ordning för att undvika systematiska effekter av testordning.

    Resultat

    Medelskillnaden i energiutgift vid spelande av tennis på Wii jämfört med PS2 beräknades till 1,85 kcal/min (95 % CI: 1,43–2,27). Vid boxning var medelskillnaden mellan Wii och PS2 3,93 kcal/min (95 % CI: 3,27–4,60). Medelskillnaden i hjärtfrekvens vid spelande av tennis på Wii jämfört med PS2 mättes till 20,56 slag/min (95 % CI: 14,90–26,21). Vid boxning var medelskillnaden mellan Wii och PS2 37,83 slag/min (95 % CI: 28,81–46,85). Energiutgiften vid boxning på Wii kan jämföras med den vid rask promenad eller lätt jogging. Beroende på vilket spel som väljs att spela tyder resultaten på att regelbunden användning av Wii skulle kunna bidra till bibehållande av kroppsvikt detta förutsatt att spelande ersätter en annars mindre energikrävande aktivitet eller sysselsättning såsom traditionellt TV-spelande eller stillasittande.

    Slutsats

    Slutsatsen av våra resultat är att det föreligger en skillnad i energiutgift vid spel av liknande art på Nintendo Wii och Sony Playstation 2. Det är även tydligt att beroende på vilket spel som väljs till konsolen varierar energiutgiften. Det går heller inte att utesluta att regelbundet spelande skulle kunna leda till en viktreducering som följd av en förhöjd energiförbrukning hos användaren.

  • 76.
    Ivarsson, Niklas
    et al.
    Karolinska Institutet.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Cheng, Arthur J
    Karolinska Institutet.
    Bruton, Joseph D
    Karolinska Institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Lanner, Johanna T
    Karolinska Institutet.
    Westerblad, Håkan
    Karolinska Institutet.
    SR Ca2+ leak in skeletal muscle fibers acts as an intracellular signal to increase fatigue resistance.2019In: The Journal of General Physiology, ISSN 0022-1295, E-ISSN 1540-7748, article id jgp.201812152Article in journal (Refereed)
    Abstract [en]

    Effective practices to improve skeletal muscle fatigue resistance are crucial for athletes as well as patients with dysfunctional muscles. To this end, it is important to identify the cellular signaling pathway that triggers mitochondrial biogenesis and thereby increases oxidative capacity and fatigue resistance in skeletal muscle fibers. Here, we test the hypothesis that the stress induced in skeletal muscle fibers by endurance exercise causes a reduction in the association of FK506-binding protein 12 (FKBP12) with ryanodine receptor 1 (RYR1). This will result in a mild Ca2+ leak from the sarcoplasmic reticulum (SR), which could trigger mitochondrial biogenesis and improved fatigue resistance. After giving mice access to an in-cage running wheel for three weeks, we observed decreased FKBP12 association to RYR1, increased baseline [Ca2+]i, and signaling associated with greater mitochondrial biogenesis in muscle, including PGC1α1. After six weeks of voluntary running, FKBP12 association is normalized, baseline [Ca2+]i returned to values below that of nonrunning controls, and signaling for increased mitochondrial biogenesis was no longer present. The adaptations toward improved endurance exercise performance that were observed with training could be mimicked by pharmacological agents that destabilize RYR1 and thereby induce a modest Ca2+ leak. We conclude that a mild RYR1 SR Ca2+ leak is a key trigger for the signaling pathway that increases muscle fatigue resistance.

  • 77.
    Jacobsson, Staffan
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Lindblom, Ida
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    GIH:s Gångtest: hur korrelerar resultaten från GIH:s gångtest med bestämd maximal syreupptagningsförmåga?2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Aim

    The aim was to correlate the result on GIH:s walk test with the determined maximum oxygen uptake (VO2max). The question was if GIH:s walk test can be used as an alternative to estimate maximum oxygen uptake in healthy physical active young adults?

    Methods

    In this study 45 physical active persons (26 women and 19 men) at the age of 19-28 years participated. The two tests that have been carried out are GIH:s walk test ( a 6-minute walk test) and determined maximum oxygen uptake during running on a treadmill.

    GIH:s walk test is a shuttle test in which the participant (P) walks a 50 meters long distance back and forth between two cones. P shall walk this distance as many times as possible during 6 minutes. At the end of the test, maximum walk distance, pulse and rank of effort were measured.

    The test to determine maximum oxygen uptake was performed running on a treadmill. During the first 2 minutes the treadmill was elevated 1 degree. The elevation increased 1 degree every minute until the participant reached her maximum oxygen uptake, whereupon the test was interrupted. Every 15 second the participants heart rate, VO2 (l/min), VCO2 (l/min), bodyweight/min (ml/kg/min) was registered by means of an online system.

    Results

    The correlation coefficient between walked distance and VO2max for all 45 participants in this study was 0.16. This means that the correlation between GIH:s walk test and maximum oxygen uptake is very weak in the present material of healthy physical active young adults between 19-28 years. Thus GIH:s walk test is not an alternative to use for determination of maximum oxygen uptake capacity in this group of persons. 

    Conclusion

    GIH:s walk test prove to have a weak correlation with maximum oxygen uptake, for healthy physical active younger adults.

  • 78.
    Jansson, Daniel
    et al.
    Swedish School of Sport and Health Sciences, GIH. Umeå universitet.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Effects of Unilateral Versus Bilateral Complex Training Combined with High Intensity Interval Training on the Development of Strength, Power and Athletic Performance for Elite Handball Players2016Conference paper (Refereed)
    Abstract [en]

    Introduction

    Unilateral (UL) training as an alternative method for developing athletic performance are not well studied (1, 2). The purpose is to examine the effects of bilateral (BL) versus UL complex training combined with high intensity interval training (HIIT) on bilateral deficit (BLD), power deficit, maximal strength, jumping ability, straight sprint, change of direction sprint (CODS), repeated sprint ability (RSA) and specific endurance in elite handball players.

    Methods

    18 male and 12 female elite handball players were assigned to a BL (n=10) or UL (n=20) complex training program. In addition both groups trained HIIT twice a week. Training volume, intensity and exercise motions were similar between the groups. Tests included 1RM UL and BL Smith machine squat, UL and BL counter movement jump (CMJ), squat jump (SJ), modified T-test, straight sprint (5, 10, 20 and 30 m), repeated shuttle sprint ability (RSSA) and Yo-Yo Intermittent Recovery test (YYIR) before and after 6 weeks of training.

    Results

    Pooled data from both groups showed significant (p <0.01) improvements in maximal UL and BL strength, UL CMJ dominant leg, CODS and YYIR test, and an unwanted increase in the BLD and power deficit.

    There were no significant differences training groups in any of the tests. However, only the UL group significantly improved RSAtotal pre- to post testing (p < 0.01).

    Discussion

    Results indicate that this type of training is a relevant model for pre-season training of maximal strength, power and functional endurance. Despite the lack of differences between groups, UL training can be safer than BL training because of less absolute load.

    1) Jones MT, Ambeganokar JP, Nindl BC, Smith JA, Headley SA. (2012). J Strength Cond Res, 26(4), 1094-100

    2) McCurdy K, Langford G, Doscher MW, Wiley LP, Mallard KG. (2005). J Strength Cond Res, 19(1), 9-15

  • 79. Jeppesen, Jacob
    et al.
    Mogensen, Martin
    Prats, Clara
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Madsen, Klavs
    Kiens, Bente
    Copenhagen University.
    FAT/CD36 is localized in sarcolemma and in vesicle-like structures in subsarcolemma regions but not in mitochondria.2010In: Journal of Lipid Research, ISSN 0022-2275, E-ISSN 1539-7262, Vol. 51, no 6, p. 1504-12Article in journal (Refereed)
    Abstract [en]

    The primary aim of the present study was to investigate in which cellular compartments fatty acid trans-locase CD36 (FAT/CD36) is localized. Intact and fully functional skeletal muscle mitochondria were isolated from lean and obese female Zucker rats and from 10 healthy male individuals. FAT/CD36 could not be detected in the isolated mitochondria, whereas the mitochondrial marker F(1)ATPase-beta was clearly detected using immunoblotting. Lack of markers for other membrane structures indicated that the mitochondria were not contaminated with membranes known to contain FAT/CD36. In addition, fluorescence immunocytochemistry was performed on single muscle fibers dissected from soleus muscle of lean and obese Zucker rats and from the vastus lateralis muscle from humans. Costaining against FAT/CD36 and MitoNEET clearly show that FAT/CD36 is highly present in sarcolemma and it also associates with some vesicle-like intracellular compartments. However, FAT/CD36 protein was not detected in mitochondrial membranes, supporting the biochemical findings. Based on the presented data, FAT/CD36 seems to be abundantly expressed in sarcolemma and in vesicle-like structures throughout the muscle cell. However, FAT/CD36 is not present in mitochondria in rat or human skeletal muscle. Thus, the functional role of FAT/CD36 in lipid transport seems primarily to be allocated to the plasma membrane in skeletal muscle.

  • 80. Kim, Chang
    et al.
    Takala, Timo
    Seger, Jan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Karpakka, Jarmo
    Training effects of electrically induced dynamic contractions in human quadriceps muscle.1995In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 66, p. 251-255Article in journal (Refereed)
    Abstract [en]

    The effects of electrically induced dynamic muscle contractions on muscle endurance, strength, morphology and enzymatic adaptation were studied in seven male physical education students. The training program consisted of electrically induced one-leg extensions on a modified Krogh cycle with a 30-Watt (W) load for 60 min, 3 times a week for 4 weeks. Muscle fiber type composition was unchanged, but diffusional capacity was increased after electromyostimulation training. The endurance capacity in the trained leg increased by 82% (p < 0.01), but there were no significant changes in citrate synthase, phosphofructokinase activities, and carbonic anhydrase III and myoglobin contents, suggesting that neural adaptation and learning were more important factors for the increased endurance capacity than enzymatic adaptation. Prolyl 4-hydroxylase activity, a marker of collagen biosynthesis, increased 3-fold (p < 0.01) as a result of the training. This could be due to muscle damage caused by electrically induced muscle contractions. In conclusion, electrically induced dynamic muscle contractions can increase muscle endurance without clear concominant changes in muscle morphologic and enzymatic adaptation. Increased prolyl 4-hydroxylase activity could suggest muscle damage caused by electrically induced muscle contractions.

  • 81.
    Krustrup, Peter
    et al.
    Inst of exercise and sport sciences dept of human physiology, August Krogh inst, University of Copenhagen .
    Secher, Niels H
    Relu, Mihai U
    Hellsten, Ylva
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bangsbo, Jens
    Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans.2008In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 586, no Pt 24, p. 6037-48Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W without (CON) and with (CUR) arterial injections of the non-depolarizing neuromuscular blocking agent cisatracurium. In CUR, creatine phosphate (CP) was unaltered in slow twitch (ST) fibres and decreased (P < 0.05) by 28% in FT fibres, whereas in CON, CP decreased (P < 0.05) by 33% and 23% in ST and FT fibres, respectively. From 127 s of exercise, muscle VO2 was higher (P < 0.05) in CUR compared to CON (425 +/- 25 (+/- S.E.M.) versus 332 +/- 30 ml min(-1)) and remained higher (P < 0.05) throughout exercise. Using monoexponential fitting, the time constant of the exercise-induced muscle VO2 response was slower (P < 0.05) in CUR than in CON (55 +/- 6 versus 33 +/- 5 s). During CUR and CON, muscle homogenate CP was lowered (P < 0.05) by 32 and 35%, respectively, and also muscle lactate production was similar in CUR and CON (37.8 +/- 4.1 versus 35.2 +/- 6.2 mmol). Estimated total muscle ATP turnover was 19% higher (P < 0.05) in CUR than in CON (1196 +/- 90 versus 1011 +/- 59 mmol) and true mechanical efficiency was lower (P < 0.05) in CUR than in CON (26.2 +/- 2.0 versus 30.9 +/- 1.5%). In conclusion, the present findings provide evidence that FT fibres are less efficient than ST fibres in vivo at a contraction frequency of 1 Hz, and that the muscle VO2 kinetics is slowed by FT fibre activation.

  • 82. Krustrup, Peter
    et al.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mohr, Magni
    Bangsbo, Jens
    Slow-twitch fiber glycogen depletion elevates moderate-exercise fast-twitch fiber activity and O2 uptake.2004In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 36, no 6, p. 973-82Article in journal (Refereed)
    Abstract [en]

    PURPOSE: We tested the hypotheses that previous glycogen depletion of slow-twitch (ST) fibers enhances recruitment of fast-twitch (FT) fibers, elevates energy requirement, and results in a slow component of VO2 during moderate-intensity dynamic exercise in humans. METHODS: Twelve healthy, male subjects cycled for 20 min at approximately 50% VO2max with normal glycogen stores (CON) and with exercise-induced glycogen depleted ST fibers (CHO-DEP). Pulmonary VO2 was measured continuously and single fiber, muscle homogenate, and blood metabolites were determined repeatedly during each trial. RESULTS: ST fiber glycogen content decreased (P < 0.05) during CON (293 +/- 24 to 204 +/- 17 mmol x kg d.w.), but not during CHO-DEP (92 +/- 22 and 84 +/- 13 mmol x kg d.w.). FT fiber CP and glycogen levels were unaltered during CON, whereas FT fiber CP levels decreased (29 +/- 7%, P < 0.05) during CHO-DEP and glycogen content tended to decrease (32 +/- 14%, P = 0.07). During CHO-DEP, VO2 was higher (P < 0.05) from 2 to 20 min than in CON (0-20 min:7 +/- 1%). Muscle lactate, pH and temperature, ventilation, and plasma epinephrine were not different between trials. From 3 to 20 min of CHO-DEP, VO2 increased (P <0.05) by 5 +/- 1% from 1.95 +/- 0.05 to 2.06 +/- 0.08 L x min but was unchanged during CON. In this exercise period, muscle pH and blood lactate were unaltered in both trials. Exponential modeling revealed a slow component of VO2 equivalent to 0.12 +/- 0.04 L x min during CHO-DEP. CONCLUSION: This study demonstrates that previous glycogen depletion of ST fibers enhances FT fiber recruitment, elevates O2 cost, and causes a slow component of VO2 during dynamic exercise with no blood lactate accumulation or muscular acidosis. These findings suggest that FT fiber recruitment elevates energy requirement of dynamic exercise in humans and support an important role of active FT fibers in producing the slow component of VO2

  • 83.
    Krustrup, Peter
    et al.
    Inst of exercise and sport sciences, Dept of human physiology August Krogh Institute University of Copenhagen.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mohr, Magni
    Bangsbo, Jens
    The slow component of oxygen uptake during intense, sub-maximal exercise in man is associated with additional fibre recruitment.2004In: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 447, no 6, p. 855-66Article in journal (Refereed)
    Abstract [en]

    Single muscle fibre metabolites and pulmonary oxygen uptake (VO2) were measured during moderate and intense, sub-maximal exercise to test the hypothesis that additional fibre recruitment is associated with the slow component of VO2. Seven healthy, male subjects performed 20 min moderate (MOD, approximately 50% of VO(2,max)) and intense (INT, approximately 80% VO(2,max)) cycling at 70 rpm. Glycogen content decreased significantly in type I and IIa fibres during INT, but only in type I fibres during MOD. During INT, creatine phosphate (CP) content decreased significantly both in types I and II fibres in the first 3 min (DeltaCP: 16.0+/-2.7 and 16.8+/-4.7 mmol kg(-1) d.w., respectively) and in the next 3 min (DeltaCP: 16.2+/-4.9 and 25.7+/-6.7 mmol kg(-1) d.w., respectively) with no further change from 6-20 min. CP content was below the pre-exercise level (mean-1 SD) in 11, 37, 70 and 74% of the type I fibres after 0, 3, 6 and 20 min of INT, respectively, and in 13, 45, 83 and 74% of the type II fibres. During INT, VO2 increased significantly by 6+/-1 and 4+/-1% in the periods 3-6 and 6-20 min, respectively (Delta VO(2,(6-3 min)): 0.14+/-0.02 l min(-1)), whereas VO2 was unchanged from 3 to 20 min of MOD. Exponential fitting revealed a slow component of VO2 during INT that appeared after approximately 2.6 min and amounted to 0.24 l min(-1). The present study demonstrates that additional type I and II fibres are recruited with time during intense sub-maximal exercise in temporal association with a significant slow component of VO2.

  • 84.
    Krustrup, Peter
    et al.
    Inst of exercise and sport sciences, dept of human physiology, August Krogh Institut, University of Copenhagen.
    Söderlund, Karin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mohr, Magni
    González-Alonso, José
    Bangsbo, Jens
    Recruitment of fibre types and quadriceps muscle portions during repeated, intense knee-extensor exercise in humans.2004In: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 449, no 1, p. 56-65Article in journal (Refereed)
    Abstract [en]

    To investigate recruitment of slow-twitch (ST) and fast-twitch (FT) muscle fibres, as well as the involvement of the various quadriceps femoris muscle portions during repeated, intense, one-legged knee-extensor exercise, 12 healthy male subjects performed two 3-min exercise bouts at approximately 110% maximum thigh O2 consumption (EX1 and EX2) separated by 6 min rest. Single-fibre metabolites were determined in successive muscle biopsies obtained from the vastus lateralis muscle (n = 6) and intra-muscular temperatures were continuously measured at six quadriceps muscle sites (n = 6). Creatine phosphate (CP) had decreased (P < 0.05) by 27, 73 and 88% in ST fibres and 25, 71 and 89% in FT fibres after 15 and 180 s of EX1 and after 180 s of EX2, respectively. CP was below resting mean-1 SD in 15, 46, 84 and 100% of the ST fibres and 9, 48, 85 and 100% of the FT fibres at rest, after 15 and 180 s of EX1 and after 180 s of EX2, respectively. A significant muscle temperature increase (deltaTm) occurred within 2-4 s at all quadriceps muscle sites. DeltaTm varied less than 10% between sites during EX1, but was 23% higher (P < 0.05) in the vastus lateralis than in the rectus femoris muscle during EX2. DeltaTm in the vastus lateralis was 101 and 109% of the mean quadriceps value during EX1 and EX2, respectively. We conclude that both fibre types and all quadriceps muscle portions are recruited at the onset of intense knee-extensor exercise, that essentially all quadriceps muscle fibres are activated during repeated intense exercise and that metabolic measurements in the vastus lateralis muscle provide a good indication of the whole-quadriceps muscle metabolism during repeated, intense, one-legged knee-extensor exercise.

  • 85.
    Larsen, Filip
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Effects of dietary nitrate on oxygen cost during exercise2007In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 191, no 1, p. 59-66Article in journal (Refereed)
    Abstract [en]

    AIM: Nitric oxide (NO), synthesized from l-arginine by NO synthases, plays a role in adaptation to physical exercise by modulating blood flow, muscular contraction and glucose uptake and in the control of cellular respiration. Recent studies show that NO can be formed in vivo also from the reduction of inorganic nitrate (NO(3) (-)) and nitrite (NO(2) (-)). The diet constitutes a major source of nitrate, and vegetables are particularly rich in this anion. The aim of this study was to investigate if dietary nitrate had any effect on metabolic and circulatory parameters during exercise. METHOD: In a randomized double-blind placebo-controlled crossover study, we tested the effect of dietary nitrate on physiological and metabolic parameters during exercise. Nine healthy young well-trained men performed submaximal and maximal work tests on a cycle ergometer after two separate 3-day periods of dietary supplementation with sodium nitrate (0.1 mmol kg(-1) day-1) or an equal amount of sodium chloride (placebo). RESULTS: The oxygen cost at submaximal exercise was reduced after nitrate supplementation compared with placebo. On an average Vo(2) decreased from 2.98 +/- 0.57 during CON to 2.82 +/- 0.58 L min(-1) during NIT (P < 0.02) over the four lowest submaximal work rates. Gross efficiency increased from 19.7 +/- 1.6 during CON to 21.1 +/- 1.3% during NIT (P < 0.01) over the four lowest work rates. There was no difference in heart rate, lactate [Hla], ventilation (VE), VE/Vo(2) or respiratory exchange ratio between nitrate and placebo during any of the submaximal work rates. CONCLUSION: We conclude that dietary nitrate supplementation, in an amount achievable through a diet rich in vegetables, results in a lower oxygen demand during submaximal work. This highly surprising effect occurred without an accompanying increase in lactate concentration, indicating that the energy production had become more efficient. The mechanism of action needs to be clarified but a likely first step is the in vivo reduction of dietary nitrate into bioactive nitrogen oxides including nitrite and NO.

  • 86.
    Larsen, Filip
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Weitzberg, Eddie
    Lundberg, Jon
    Effects of dietary nitrate on blood pressure in healthy volunteers2006In: New England Journal of Medicine, ISSN 0028-4793, E-ISSN 1533-4406, Vol. 28, no 355(26), p. 2792-3Article in journal (Refereed)
    Abstract [en]

    To the Editor:

    Nitric oxide, generated by nitric oxide synthase, is a key regulator of vascular integrity. This system is dysfunctional in many cardiovascular disorders, including hypertension. A fundamentally different pathway for the generation of nitric oxide was recently described in which the anions nitrate (NO3 ) and nitrite (NO2 ) are converted into nitric oxide and other bioactive nitrogen oxides.1-3 Nitrate is abundant in our diet, and particularly high levels are found in many vegetables.3

    We examined the effect of 3-day dietary supplementation with either sodium nitrate (at a dose of 0.1 mmol per kilogram of body weight per day) or placebo (sodium chloride, at a dose of 0.1 mmol per kilogram per day) on blood pressure in 17 physically active, healthy volunteers, none of whom smoked (15 men and 2 women; mean age, 24 years). The study had a randomized, double-blind, crossover design with two different treatment periods during which the subjects received either nitrate or placebo; the treatment periods were separated by a washout period of at least 10 days. The compounds were dissolved in water and could not be distinguished by taste or appearance. During the two treatment periods, the subjects were instructed to avoid all foods with a moderate or high nitrate content.3

    Systolic blood pressure Effects of 3-Day Dietary Supplementation with Inorganic Nitrate or Placebo on Systolic (Panel A) and Diastolic (Panel B) Blood Pressure in 17 Healthy Volunteers.) and pulse rate did not change significantly after nitrate supplementation, as compared with placebo supplementation. However, the diastolic blood pressure was on average 3.7 mm Hg lower after nitrate supplementation than after placebo supplementation (P<0.02) (Figure 1B), and the mean arterial pressure was 3.2 mm Hg lower (P<0.03). Plasma nitrate levels were higher after nitrate ingestion than after placebo ingestion (mean [±SD], 178±51 and 26±11 μM, respectively; P<0.001), as were plasma nitrite levels (219±105 and 138±38 nM, respectively; P<0.01).

    The daily nitrate dose used in the study corresponds to the amount normally found in 150 to 250 g of a nitrate-rich vegetable such as spinach, beetroot, or lettuce. It is clear from earlier studies, such as the Dietary Approaches to Stop Hypertension (DASH) trial, that a diet rich in fruits and vegetables can reduce blood pressure,4,5 but attempts to modify single nutrients have been inconsistent. Therefore, it has been argued that the effect of any individual nutrient is too small to detect in trials. In our study, reduced blood pressure was associated with nitrate supplementation alone; this effect was evident in young normotensive subjects. In fact, it was similar to that seen in the healthy control group in the DASH study.4 The exact mechanism behind the blood-pressure–lowering effect of nitrate needs to be clarified in future studies.

    We conclude that short-term dietary supplementation with inorganic nitrate reduces diastolic blood pressure in healthy young volunteers.

  • 87.
    Larsen, Filip J
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Weitzberg, Eddie
    Lundberg, Jon O
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Dietary nitrate reduces maximal oxygen consumption while maintaining work performance in maximal exercise.2010In: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 48, no 2, p. 342-7Article in journal (Refereed)
    Abstract [en]

    The anion nitrate-abundant in our diet-has recently emerged as a major pool of nitric oxide (NO) synthase-independent NO production. Nitrate is reduced stepwise in vivo to nitrite and then NO and possibly other bioactive nitrogen oxides. This reductive pathway is enhanced during low oxygen tension and acidosis. A recent study shows a reduction in oxygen consumption during submaximal exercise attributable to dietary nitrate. We went on to study the effects of dietary nitrate on various physiological and biochemical parameters during maximal exercise. Nine healthy, nonsmoking volunteers (age 30+/-2.3 years, VO(2max) 3.72+/-0.33 L/min) participated in this study, which had a randomized, double-blind crossover design. Subjects received dietary supplementation with sodium nitrate (0.1 mmol/kg/day) or placebo (NaCl) for 2 days before the test. This dose corresponds to the amount found in 100-300 g of a nitrate-rich vegetable such as spinach or beetroot. The maximal exercise tests consisted of an incremental exercise to exhaustion with combined arm and leg cranking on two separate ergometers. Dietary nitrate reduced VO(2max) from 3.72+/-0.33 to 3.62+/-0.31 L/min, P<0.05. Despite the reduction in VO(2max) the time to exhaustion trended to an increase after nitrate supplementation (524+/-31 vs 563+/-30 s, P=0.13). There was a correlation between the change in time to exhaustion and the change in VO(2max) (R(2)=0.47, P=0.04). A moderate dietary dose of nitrate significantly reduces VO(2max) during maximal exercise using a large active muscle mass. This reduction occurred with a trend toward increased time to exhaustion implying that two separate mechanisms are involved: one that reduces VO(2max) and another that improves the energetic function of the working muscles.

  • 88.
    Larsen, Filip
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Schiffer, TA
    Borniquel, S
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Lundberg, JO
    Weitzberg, E
    Dietary inorganic nitrate improves mitochondrial efficiency in humans.2011In: Cell Metabolism, ISSN 1550-4131, Vol. 13, no 2, p. 149-159Article in journal (Refereed)
    Abstract [en]

    Nitrate, an inorganic anion abundant in vegetables, is converted in vivo to bioactive nitrogen oxides including NO. We recently demonstrated that dietary nitrate reduces oxygen cost during physical exercise, but the mechanism remains unknown. In a double-blind crossover trial we studied the effects of a dietary intervention with inorganic nitrate on basal mitochondrial function and whole-body oxygen consumption in healthy volunteers. Skeletal muscle mitochondria harvested after nitrate supplementation displayed an improvement in oxidative phosphorylation efficiency (P/O ratio) and a decrease in state 4 respiration with and without atractyloside and respiration without adenylates. The improved mitochondrial P/O ratio correlated to the reduction in oxygen cost during exercise. Mechanistically, nitrate reduced the expression of ATP/ADP translocase, a protein involved in proton conductance. We conclude that dietary nitrate has profound effects on basal mitochondrial function. These findings may have implications for exercise physiology- and lifestyle-related disorders that involve dysfunctional mitochondria.

  • 89.
    Liegnell, Rasmus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Do different levels of lactate have an impact on mTORC1-signal and protein synthesis induced by resistance exercise?2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Aim: To investigate the role of lactate as a potential signaling molecule, for the molecular mechanisms underlying acute resistance exercise adaptation in the muscle cell.   

    Method: Four women and four men recruited to perform two trials of unilateral leg extension exercise performed with either an infusion of sodium lactate or isotonic saline (placebo), in a randomized, blinded, crossover fashion. To enable measurement of muscle protein FSR, an oral dose of 2H2O was consumed the day before the trials. Sixteen blood samples were taken for direct analysis of lactate, glucose, Na+, K+ and pH. Five muscle biopsies were obtained from vastus lateralis during each trial and analyzed for 2H-protein incorporation using mass spectrometry. Furthermore, in sampled muscle tissue, the degree of protein phosphorylation in the mTORC1 signaling pathway was determined by immunoblotting and levels of lactate were determined spectrophotometrically.    

    Results: There were no significant differences in load, repetitions or time under tension between the trials. Blood levels of lactate reached a maximal level of 3.00 ± 0.26 mmol/L post 6th set in the placebo trial (P<0.05 vs. Rest). In the lactate trial, a peak of 6.94 ± 0.47 mmol/L was reached post 6th set with levels significantly higher than placebo up to 45 min recovery (P<0.05 vs. Rest and Placebo). In both trials the muscle levels of lactate increased above rest both post exercise and following 90 min of recovery, with significantly higher levels in the lactate trial (P<0.05 vs. Rest and Placebo). The phosphorylation of mTOR at Ser2448, p70S6K1 at Thr389, and p44 at Thr202/Tyr204 increased immediately after resistance exercise and remained elevated throughout the entire recovery period (P<0.05). The phosphorylation of PRAS40 at Ser183, 4E-BP1 both at Ser65 and Thr37-46 decreased immediately after resistance exercise, whereas that of eEF2 at Thr56 decreased following 90 and 180 min of recovery (P<0.05). There were no differences between trials for any intracellular signaling protein on group basis.  

    Conclusion: An infusion of a sodium lactate solution during resistance exercise increases whole venous blood and muscle levels of lactate, without altering time under tension, load or repetition lifted during exercise. Resistance exercised induced mTORC1-signaling is not altered by a sodium lactate infusion at the group level in this population but there are underpowered differences between men and women.

    The full text will be freely available from 2020-12-13 13:52
  • 90.
    Lindberg, Thomas
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Arndt, Anton
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Norrbrink, Cecilia
    Department of Clinical Sciences, Karolinska Institutet Danderyd Hospital, Stockholm, Sweden.
    Wahman, Kerstin
    Department of Neurobiology, Care Sciences and Society (NVS), Division of Neurorehabilitation, Karolinska Institutet.
    Bjerkefors, Anna
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Effects of seated double-poling ergometer training on aerobic and mechanical power in individuals with spinal cord injury2012In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 44, no 10, p. 893-898Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To determine whether regular interval training on a seated double-poling ergometer can increase physical capacity and safely improve performance towards maximal level in individuals with spinal cord injury.

    METHODS: A total of 13 subjects with spinal cord injury (injury levels T5-L1) performed 30 sessions of seated double-poling ergometer training over a period of 10 weeks. Sub-maximal and maximal double-poling ergometer tests were performed before (test-retest) and after this training period. Oxygen uptake was measured using the Douglas Bag system. Three-dimensional kinematics were recorded using an optoelectronic system and piezoelectric force sensors were used to register force in both poles.

    RESULTS: The mean intra-class correlation coefficient for test-retest values was 0.83 (standard deviation 0.11). After training significant improvements were observed in people with spinal cord injury in oxygen uptake (22.7%), ventilation (20.7%) and blood lactate level (22.0%) during maximal exertion exercises. Mean power per stroke and peak pole force increased by 15.4% and 23.7%, respectively. At sub-maximal level, significantly lower values were observed in ventilation (-12.8%) and blood lactate level (-25.0%).

    CONCLUSION: Regular interval training on the seated double-poling ergometer was effective for individuals with spinal cord injury below T5 level in terms of improving aerobic capacity and upper-body power output. The training was safe and did not cause any overload symptoms.

  • 91.
    Lännerström, Johan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Mitokondriella proteiner i snabba och långsamma muskelfibrer2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Aim

    The puropse of this study was to investigate whether the expression of and the relation between mitochondrial proteins, that are associated with oxidative stress, differs among slow twitch and fast twitch muscle fibers. Research questions: 1) Does the prevalence of the proteins Uncoupling protein 3 (UCP3), Adenine Nucleotide Translocator (ANT isoform-1 & 2) and Superoxide Dismutase (SOD2) differ in fast and slow twitch muscle fibers when normalized for mitochondrial density? 2) Is there any difference in above mentioned proteins plus Catalase in expression between fast and slow twitch fibers when normalized for total protein content?

    Method

    Single muscle fibers were dissected from 8 freeze dried biopsies in 4 men, taken in the Vastus Lateralis, and analyzed with immunoblotting. Fibers were classified as type-1 (MHC-I) or type-2 (MHC-II) and then further analyzed for their protein content. Citrate Synthase was used as a marker to normalize for mitochondrial density while Reactive Brown was used to normalize for total protein content loaded.

    Results

    ANT-2 showed a tendency to be 59 % more abundant in the mitochondria of type-2 fibers (P=0,052). No other statistical differences after normalization for mitochondrial density were found. When normalizing for total protein, ANT-1 (P=0,01), SOD2 (P=0,002), CS (P=0,01) and ANT-2 (P=0,003) showed statistical significance to be more abundant in typ-1 fibers with 10, 25, 8 and 58% respectively. UCP3 showed a tendency to statistical significance (P=0,052) to be 27 % more abundant in type-1 fibers while Catalase did not show any difference in expression between the fiber types.

    Conclusions

    There seems to be no general differences between mitochondria in type-1 and type-2 fibers based on these results. However, the mitochondrial proteins are more expressed in type-1 fibers, which indicates that more mitochondria exist in the type-1 fibers. Nevertheless, it should not be ruled out that differences on mitochondrial level actually do exist given that no results reached statistical significance. The biggest discovery in this study was that UCP3 showed tendency to be more expressed in type-1 fibers, which contradicts existing literature on human skeletal muscle.

  • 92. Mandroukas, A
    et al.
    Heller, J
    Metaxas, T I
    Christoulas, K
    Vamvakoudis, E
    Stefanidis, P
    Papavasileiou, A
    Kotoglou, K
    Balasas, D
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mandroukas, K
    Deltoid muscle characteristics in wrestlers.2010In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 31, no 3, p. 148-53Article in journal (Refereed)
    Abstract [en]

    The purpose of the present study was to investigate the deltoid muscle characteristics of wrestlers. Nine Greco-Roman competitive male wrestlers (mean age 20.1+/-2.7 yrs, height 175+/-0.6 cm, weight 83.2+/-12.5 kg, years of training 7.6+/-2.7 yrs) participated in this study. Six male healthy sedentary students (mean age 21.2+/-0.9 yrs, height 180+/-0.3 cm, weight 80.1+/-9.4 kg) served as controls. Muscle fibre distribution, cross-sectional area (CSA), as well as satellite cells, myonuclei and capillary density per muscle fibre area were determined by immunohistochemistry. Myosin heavy chain MHC isoform composition of single fibres was determined with protein electrophoresis. Immunohistochemical analysis showed that muscle fibre distribution of the MHC I and IIA were significantly higher in wrestlers than in controls (p<0.05). Electrophoretic analysis of single fibres revealed a significantly higher proportion of fibres containing MHC I and IIC in wrestlers (p<0.05). The mean CSA of type IIA fibres and the number of myonuclei per type II was significantly higher in wrestlers (p<0.05). We also found that the number of satellite cells was 2.5 fold higher in wrestlers than in the control group. This study suggests that the observed muscle fibre profile in the deltoid of wrestlers may represent an adaptation based on the specific mechanical and biochemical demands of the long-term training in Greco-Roman wrestling.

  • 93. Mandroukas, A
    et al.
    Metaxas, T
    Kesidis, N
    Christoulas, K
    Vamvakoudis, E
    Stefanidis, P
    Heller, J
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Mandroukas, K
    Deltoid muscle fiber characteristics in adolescent and adult wrestlers.2010In: Journal of Sports Medicine and Physical Fitness, ISSN 0022-4707, E-ISSN 1827-1928, Vol. 50, no 2, p. 113-20Article in journal (Refereed)
    Abstract [en]

    Our findings suggest that the observed muscle fiber profile in the deltoid muscle of wrestlers may represent an adaptation based on the mechanical and biochemical demands of the long-term training. Such adaptations are linked to the specific characteristics of the training program, the level and the previous training experience of the wrestlers.

  • 94.
    Manselin, Tom A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Södergård, Olof
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Larsen, Filip J
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Research group for Mitokondriell funktion och metabolisk kontroll.
    Lindholm, Peter
    Karolinska institutet.
    Aerobic efficiency is associated with the improvement in maximal power output during acute hyperoxia.2017In: Physiological Reports, E-ISSN 2051-817X, Vol. 5, no 2, article id e13119Article in journal (Refereed)
    Abstract [en]

    This study investigated the relationship between aerobic efficiency during cycling exercise and the increase in physical performance with acute hyperoxic exposure (FiO2 ~31%) (HOX) and also tested the hypothesis that fat oxidation could be increased by acute hyperoxia. Fourteen males and four females were recruited for two sessions, where they exercised for 2 × 10 min at 100 W to determine efficiency. HOX and normoxia (NOX) were administered randomly on both occasions to account for differences in nitrogen exchange. Thereafter, a progressive ramp test was performed to determine VO2max and maximal power output (Wmax). After 30 min rest, workload was set to 80% of maximal power output (Wmax) for a time to exhaustion test (TTE). At 100W gross efficiency was reduced from 19.4% during NOX to 18.9% during HOX (P ≤ 0.0001). HOX increased fat oxidation at 100 W by 52% from 3.41 kcal min(-1) to 5.17 kcal min(-1) (P ≤ 0.0001) with a corresponding reduction in carbohydrate oxidation. Wmax increased by 2.4% from 388.8 (±82.1) during NOX to 397.8 (±83.5) during HOX (P ≤ 0.0001). SaO2 was higher in HOX both at the end of the maximal exercise test and TTE. Subjects with a high level of efficiency in NOX had a larger improvement in Wmax with HOX, in agreement with the hypothesis that an optimum level of efficiency exists that maximizes power production. No association between mitochondrial excess capacity and endurance performance was found; increases in oxygen supply seemed to increase maximal aerobic power production and maintain/increase endurance capacity at the same relative workload.

  • 95.
    Manselin, Tom
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Södergård, Olof
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Six weeks of high intensity interval training with hyperoxia or normoxia in trained cyclists: A polarized and periodized training approach2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Aim

    The main aim of this study was to investigate the longitudinal effects on cycling performance using a polarized and periodized scheme that was highly supervised and controlled. The second aim was to investigate the effect of using Hyperoxia. The questions used to address the aim were: (1) How does overall performance change after a six-week training intervention? (2) What is the time-course and pattern of performance changes to the training scheme? (3) How does the performance change within the groups?

     

    Method

    Nineteen male and female cyclists started the study (13 male and 6 female), however only 12 completed it (8 male and 4 female). The characteristics for the 12 subjects were:  age (year) 33.6 ± 6.8, height (cm) 177 ± 9.1, body mass (kg) 73.4 ± 8.8. Using a randomized, double blind design, the test subjects were divided in to hyperoxia (HOT) (n = 6) and normoxia (NOT) (n = 6) training groups.  Over a six week period the subjects followed a controlled polarized periodization that included 15 high intensity interval training (HIIT) sessions (3 x 8 min, 3 x 8 + 4 min, 4 x 8 min & 4 x 4 min) on maximal sustainable intensity (isoeffort) on a cycle ergometer. The dosage of oxygen was administered intermittently by the oxelerate device. A 20 min all out test was performed as pre- and post test. 

     

    Results

    The whole group (n = 12) increased mean power output (W) by 6.4 % (P = 0.002). The relative power output (W/kg) increased significantly 8.2 % (P = 0.0011). The HOT group (n = 6) increased their power output by 8.3 % (P = 0.028) and their relative power output increased by 9.4 % (P=0.011). The whole group (P = 12) significantly increased their VO2mean by 4.1 % (P = 0.03) and in the relative value by 5.4 % (P = 0.01) on the 20 min all out test. The whole group also had a significant increase in VO2peak of 3.7 % (P = 0.04). A very strong correlation could be found between the training data and the performance test.

     

    Conclusions

    The training intervention was favourable for increasing performance and VO2peak in cycling. Usage of hyperoxia during the training intervention increases the performance.

  • 96.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's and Mats Börjesson's research group.
    Factors determining ultra-endurance exercise performance2014Conference paper (Refereed)
    Abstract [en]

    This talk will focus on the major nutritional and physiological factors that influence ultra-endurance exercise performance in both recreational and elite athletes.

    Empirical observations show that athletes who have been engaged in ultra-endurance sports for several years have a large advantage compared to novices in the sport. It depends of course in part on the fact that they are more experienced, but even athletes from traditional endurance sports with a documented higher aerobic capacity (i.e., higher VO2max) have difficulties to keep up with ultra-endurance specialists when exercise duration exceeds three or four hours. This indicates that fatigue and performance in ultra-endurance exercise is determined by (in part) other factors compared to traditional endurance sports.

    Ultra-endurance sports vary in form and duration, such as running or adventure racing (AR) from 6 h to more than 6 days, but are no matter the nature of the specific competition still in many aspects extreme sports.

    The athletes do not generally need to perform at high maximum speeds, but the energy expenditure is extremely high. The total energy expenditure for a 24-h AR is approximately 18-20 000 kcal, which is almost 10 times more than normal basal metabolism (Enqvist et al. 2010). One reason for fatigue is that the energy deficit is substantial, also the profile of amino acids in blood and muscle change during races (Borgenvik et al. 2012), possibly contributing to the central fatigue that has been described in other studies.

    As for the physiological factors, our research group and collaborators have investigated many aspects of the versatile physiological adaptation to ultra-endurance exercise, such as circulatory adaptations and cardiac fatigue (Mattsson 2011, Mattsson et al. 2010, 2011) muscular damage (Wichardt et al 2011, Marklund et al 2013), hormonal status (Berg et al 2008), and immunological response (Wallberg et al 2011).

    The effect of sleep deprivation on both mental and physiological functions during the races must also be included in the total complex of factors limiting performance.

  • 97.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Konditionsträning för lagbollsidrottare2012In: Idrott & kunskap, ISSN 1652-6961, no 1, p. 46-49Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Vilka konditionstestvärden har elitspelare i fotboll, ishockey och basket? Och hur tränar man effektivast sinkondition om man är bollidrottare? Mikael Mattson, doktor i fysiologi vid GIH, reder ut begreppen.

  • 98.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Krönika: Pulsmätningen är katastrofdålig2015In: Outside Träning, ISSN 1652-4624, no 2Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Det vore ju underbart om det fungarade! Du har på dig ett armband som talar om hur mycket du tränat, hur mycket du behöver äta, hur lång återhämtningen är och hur länge du behöver sova för att vara på topp. Om du bara lyssnar på klockan blir allt perfekt.

    Tyvärr kan man inte använda dagens wearables så. De är helt enkelt för dåliga. Man får värden och siffror, men de är långt ifrån sanna eller säkra.

  • 99.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Maraton: När sprängs tvåtimmarsgränsen?2010In: Idrott & Kunskap, ISSN 1652-6961, Vol. 7, no 5, p. 52-55Article in journal (Other (popular science, discussion, etc.))
  • 100.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Multisportens fysiologi2011In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 20, no 2, p. 50-53Article in journal (Other academic)
    Abstract [sv]

    Hur klarar kroppen flera dygn av tävling med relativt hög intensitet? Multisportare genomför sina lopp, men enligt traditionella fysiologiska förklaringsmodeller borde de ramla ihop av utmattning långt innan målgång. I vårt projekt ser vi hur kroppen och hjärtat istället anpassar sig till ansträngningarna utan några tecken på hjärtmuskelcellsskador.

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