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  • 1. Adlard, Kirsten N.
    et al.
    Bolam, Kate
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Jenkins, David G.
    Skinner, Tina L.
    The influence of exercise intensity on fatigue in adults: a systematic review2016In: Research to Practice 2016: Conference Proceedings, Exercise & Sports Science Australia , 2016, p. 173-Conference paper (Other academic)
  • 2.
    Adlard, Kirsten N.
    et al.
    Univ Queensland, Sch Human Movement & Nutr Sci, Brisbane, Qld, Australia..
    Devin, James L.
    Univ Queensland, Sch Human Movement & Nutr Sci, Brisbane, Qld, Australia..
    Jenkins, David G.
    Univ Queensland, Sch Human Movement & Nutr Sci, Brisbane, Qld, Australia..
    Bolam, Kate A.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Univ Queensland, Sch Human Movement & Nutr Sci, Brisbane, Qld, Australia..
    Aitken, Joanne F.
    Griffith Univ, Menzies Hlth Inst Queensland, Gold Coast, Qld, Australia.;Canc Council Queensland, Canc Res Ctr, Brisbane, Qld, Australia..
    Chambers, Suzanne K.
    Griffith Univ, Menzies Hlth Inst Queensland, Gold Coast, Qld, Australia.;Canc Council Queensland, Canc Res Ctr, Brisbane, Qld, Australia.;Prostate Canc Fdn Australia, Sydney, NSW, Australia.;Edith Cowan Univ, Hlth & Wellness Inst, Perth, WA, Australia.;Univ Queensland, Clin Res Ctr, Brisbane, Qld, Australia..
    Dunn, Jeffrey C.
    Griffith Univ, Menzies Hlth Inst Queensland, Gold Coast, Qld, Australia.;Canc Council Queensland, Canc Res Ctr, Brisbane, Qld, Australia.;Univ Queensland, Sch Social Sci, Brisbane, Qld, Australia..
    Skinner, Tina L.
    Univ Queensland, Sch Human Movement & Nutr Sci, Brisbane, Qld, Australia..
    THE INFLUENCE OF EXERCISE INTENSITY ON FATIGUE IN COLORECTAL CANCER SURVIVORS: A RANDOMIZED CONTROLLED TRIAL2016In: Asia-Pacific Journal of Clinical Oncology, ISSN 1743-7563, E-ISSN 1743-7563, Vol. 12, no S5, p. 78-78, article id 44Article in journal (Other academic)
  • 3. Alvehus, Malin
    et al.
    Boman, Niklas
    Söderlund, Karin
    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.
    Svensson, Michael B
    Burén, Jonas
    Metabolic adaptations in skeletal muscle, adipose tissue, and whole-body oxidative capacity in response to resistance training.2014In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 114, no 7, p. 1463-1471Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The effects of resistance training on mitochondrial biogenesis and oxidative capacity in skeletal muscle are not fully characterized, and even less is known about alterations in adipose tissue. We aimed to investigate adaptations in oxidative metabolism in skeletal muscle and adipose tissue after 8 weeks of heavy resistance training in apparently healthy young men.

    METHODS: Expression of genes linked to oxidative metabolism in the skeletal muscle and adipose tissue was assessed before and after the training program. Body composition, peak oxygen uptake (VO2 peak), fat oxidation, activity of mitochondrial enzyme in muscle, and serum adiponectin levels were also determined before and after resistance training.

    RESULTS: In muscle, the expression of the genes AdipoR1 and COX4 increased after resistance training (9 and 13 %, respectively), whereas the expression levels of the genes PGC-1α, SIRT1, TFAM, CPT1b, and FNDC5 did not change. In adipose tissue, the expression of the genes SIRT1 and CPT1b decreased after training (20 and 23 %, respectively). There was an increase in lean mass (from 59.7 ± 6.1 to 61.9 ± 6.2 kg), VO2 peak (from 49.7 ± 5.5 to 56.3 ± 5.0 ml/kg/min), and fat oxidation (from 6.8 ± 2.1 to 9.1 ± 2.7 mg/kg fat-free mass/min) after training, whereas serum adiponectin levels decreased significantly and enzyme activity of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase did not change.

    CONCLUSION: Despite significant increases in VO2 peak, fat oxidation, and lean mass following resistance training, the total effect on gene expression and enzyme activity linked to oxidative metabolism was moderate.

  • 4.
    Andersson, Eva A
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Karolinska institutet.
    Frank, Per
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Karolinska institutet.
    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.
    Ekblom, Maria
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology. Karolinska institutet.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Improving Strength, Power, Muscle Aerobic Capacity, and Glucose Tolerance through Short-term Progressive Strength Training Among Elderly People.2017In: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, no 125Article in journal (Refereed)
    Abstract [en]

    This protocol describes the simultaneous use of a broad span of methods to examine muscle aerobic capacity, glucose tolerance, strength, and power in elderly people performing short-term resistance training (RET). Supervised progressive resistance training for 1 h three times a week over 8 weeks was performed by RET participants (71±1 years, range 65-80). Compared to a control group without training, the RET showed improvements on the measures used to indicate strength, power, glucose tolerance, and several parameters of muscle aerobic capacity. Strength training was performed in a gym with only robust fitness equipment. An isokinetic dynamometer for knee extensor strength permitted the measurement of concentric, eccentric, and static strength, which increased for the RET group (8-12% post- versus pre-test). The power (rate of force development, RFD) at the initial 0-30 ms also showed an increase for the RET group (52%). A glucose tolerance test with frequent blood glucose measurements showed improvements only for the RET group in terms of blood glucose values after 2 h (14%) and the area under the curve (21%). The blood lipid profile also improved (8%). From muscle biopsy samples prepared using histochemistry, the amount of fiber type IIa increased, and a trend towards a decrease in IIx in the RET group reflected a change to a more oxidative profile in terms of fiber composition. Western blot (to determine the protein content related to the signaling for muscle protein synthesis) showed a rise of 69% in both Akt and mTOR in the RET group; this also showed an increase in mitochondrial proteins for OXPHOS complex II and citrate synthase (both ~30%) and for complex IV (90%), in only the RET group. We demonstrate that this type of progressive resistance training offers various improvements (e.g., strength, power, aerobic capacity, glucose tolerance, and plasma lipid profile).

  • 5.
    Andersson, Eva A.
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Rönquist, Gustaf
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Oddsson, Kristjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Äldre blir starkare av Hälsoprojektet2013In: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, no 1, p. 25-27Article in journal (Other academic)
    Abstract [sv]

    En god kondition och styrka har samband med förbättrad hälsa, minskad förekomst av flera folksjukdomar samt ökad livslängd. Fysiologiska tester kan vara stimulerande för äldre att följa utvecklingen av sin fysiska kapacitet och för olika aktörer som vill göra hälsoutvärderingar.

  • 6.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Laboratory for Biomechanics and Motor Control.
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Hultgren, Staffan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Kraepelien Strid, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Hälsopedagogprogrammet2014In: Från Kungl. Gymnastiska Centralinstitutet till Gymnastik- och idrottshögskolan: en betraktelse av de senaste 25 åren som del av en 200-årig historia / [ed] Suzanne Lundvall, Stockholm: Gymnastik- och idrottshögskolan, GIH , 2014, p. 108-116Chapter in book (Other (popular science, discussion, etc.))
  • 7.
    Andersson, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Oddsson, Kristjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Nilsson, Johnny
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Laboratory of Applied Sports Science (LTIV).
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Wahlgren, Lina
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Research Unit for Movement, Health and Environment.
    Kjellman, Bengt
    Jonsson, Bo
    Taube, Jill
    Improved Physical Capacity in a Project with Guided Physical Activity for Persons with Depression or Anxiety.2010Conference paper (Refereed)
    Abstract [en]

    Background: Higher physical capacity is correlated with increased health. Knowledge in this area regarding psychiatric diseases is sparse. 

    Purpose: The aim was to study aerobic and several strength capacities in a physical activity project for persons with depression or anxiety.

    Methods: Eighty-four persons (56 women and 28 men) with depression or anxiety were recruited from psychiatric out-patient clinics in Stockholm. Their mean age and BMI was 46 (21-80) years and 26 (17-41) kg/m2, respectively. 50% were sick-listed. 50% had BMI>25. Aerobic and strength tests were chosen by each subgroup´s project leaders. Directed physical activity was given, in groups 10-15, 1 hour twice/week during 8-12 weeks.

    Results: Significant changes (p<0.05, of all n=84) between pre- and post tests were seen in submaximal cycle test (11% enhanced values, n=56) and distance of 6 minutes walk test (16%, n=15) as well as in strength tests for the back for the back (i.e. time in static horizontal belly-back, 40%, n=44), abdominal and hip flexors (i.e. number of hip flexion sit-ups, 45%, n=38), leg (i.e. standing with 90O in hips and knees, 48%, n=56) and arm with shoulder muscles (i.e. number of raising weights alternately with the arms, 46%, n=32). Hand grip tests, BMI or blood pressure values did not change significantly.

    Conclusions: Directed 8-12 weeks physical activity programs can improve physical fitness in individuals with depression or anxiety.

  • 8.
    Andersson, Helena
    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.
    Krustrup, Peter
    Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions.2008In: Journal of Sports Sciences, ISSN 0264-0414, E-ISSN 1466-447X, Vol. 26, no 2, p. 113-22Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.

  • 9. Andersson, Ulrika
    et al.
    Leighton, Brendan
    Young, Martin E
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Newsholme, Eric A
    Inactivation of aconitase and oxoglutarate dehydrogenase in skeletal muscle in vitro by superoxide anions and/or nitric oxide.1998In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 249, no 2, p. 512-6Article in journal (Refereed)
    Abstract [en]

    Strips of rat soleus muscle were incubated in media containing a superoxide generating system and/or the nitric oxide donor sodium nitroprusside (SNP) before the maximal catalytic activities of aconitase, citrate synthase, and oxoglutarate dehydrogenase were measured. The maximal activities of aconitase and oxoglutarate dehydrogenase were both decreased by 25-30% by superoxide anions; however, only the maximal activity of aconitase was decreased, by approximately 50%, by incubation of muscles with SNP. Furthermore, when both superoxide and NO were present in the medium, aconitase activity was decreased by 70%. The maximal activity of citrate synthase was not affected by any of the treatments. This is the first time that superoxide anions or NO has been shown to inactivate aconitase and oxoglutarate dehydrogenase in skeletal muscle. It is suggested that these effects may be responsible for some alterations in skeletal muscle metabolism, and these possibilities are discussed.

  • 10. Andréll, Paulin
    et al.
    Schultz, Tomas
    Mannerkorpi, Kaisa
    Nordeman, Lena
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Mannheimer, Clas
    Health-related quality of life in fibromyalgia and refractory angina pectoris: a comparison between two chronic non-malignant pain disorders.2014In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 46, no 4, p. 341-7Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To compare health-related quality of life in 2 different populations with chronic pain: patients with fibromyalgia and patients with refractory angina pectoris. Previous separate studies have indicated that these patient groups report different impacts of pain on health-related quality of life.

    METHODS: The Short-Form 36 was used to assess health- related quality of life. In order to adjust for age and gender differences between the groups, both patient groups were compared with age- and gender-matched normative controls. The difference in health-related quality of life between the 2 patient groups was assessed by transforming the Short-Form 36 subscale scores to a z-score.

    RESULTS: The patients with fibromyalgia (n = 203) reported poorer health-related quality of life in all the subscale scores of Short-Form 36 (p < 0.05-0.0001) than the patients with refractory angina (n = 146) when both groups were compared with their corresponding normal population (z-score).

    CONCLUSION: Patients with fibromyalgia experience greater impairment in health-related quality of life compared with the normal population than do patients with refractory angina pectoris, despite the fact that the latter have a potentially life-threatening disease. The great impairment in health- related quality of life in patients with fibromyalgia should be taken into consideration when planning rehabilitation.

  • 11. Angenete, E
    et al.
    Angerås, U
    Börjesson, Mats
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group.
    Ekelund, J
    Gellerstedt, M
    Thorsteinsdottir, T
    Steineck, G
    Haglind, E
    Physical activity before radical prostatectomy reduces sick leave after surgery - results from a prospective, non-randomized controlled clinical trial (LAPPRO).2016In: BMC Urology, ISSN 1471-2490, E-ISSN 1471-2490, Vol. 16, no 1, article id 50Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Studies have reported that early physical rehabilitation after surgical procedures is associated with improved outcome measured as shorter hospital stay and enhanced recovery. The aim of this study was to explore the relationship between the preoperative physical activity level and subsequent postoperative complications, sick-leave and hospital stay after radical prostatectomy for prostate cancer in the setting of the LAPPRO trial (LAParoscopic Prostatectomy Robot Open).

    METHODS: LAPPRO is a prospective controlled trial, comparing robot-assisted laparoscopic and open surgery for localized prostate cancer between 2008 and 2011. 1569 patients aged 64 or less with an occupation were included in this sub-study. The Gleason score was <7 in 52 % of the patients. Demographics and the level of self-assessed preoperative physical activity, length of hospital stay, complications, quality of life, recovery and sick-leave were extracted from clinical record forms and questionnaires. Multivariable logistic regression, with log-link and logit-link functions, was used to adjust for potential confounding variables.

    RESULTS: The patients were divided into four groups based on their level of activity. As the group with lowest engagement of physical activity was found to be significantly different in base line characteristics from the other groups they were excluded from further analysis. Among patients that were physically active preoperativelly (n = 1467) there was no significant difference between the physical activity-groups regarding hospital stay, recovery or complications. However, in the group with the highest self-assessed level of physical activity, 5-7 times per week, 13 % required no sick leave, compared to 6.3 % in the group with a physical activity level of 1-2 times per week only (p < 0.0001).

    CONCLUSIONS: In our study of med operated with radical prostatectomy, a high level of physical activity preoperatively was associated with reduced need for sick leave after radical prostatectomy compared to men with lower physical activity.

    TRIAL REGISTRATION: The trial is registered at the ISCRTN register. ISRCTN06393679 .

  • 12.
    Apro, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand'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.
    Holmberg, Hans-Christer
    Mittuniversitetet.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    High intensity interval cycling performed prior to resistance exercise stimulates autophagy signaling2016In: Conference program & abstracts, 2016, p. 84-84Conference paper (Other academic)
  • 13.
    Apró, William
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group. Karolinska Institutet, Inst för klinisk vetenskap, intervention och teknik / Dept of Clinical Science, Intervention and Technology.
    Regulation of protein synthesis in human skeletal muscle: separate and combined effects of exercise and amino acids2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Skeletal muscle is a highly plastic tissue which has the ability to adapt to various forms of external stimuli such as diverse modes of contractile activity. Thus, performance of endurance exercise over several of weeks results in increased oxidative capacity. In contrast, prolonged performance of resistance exercise ultimately results in increased muscle mass. These adaptations are brought about by transient alterations in gene expression and mRNA translation which result in altered protein turnover, i.e. the balance between protein synthesis and protein breakdown. Protein synthesis is the major determinant of muscle growth, which at the molecular level, is regulated by the mTORC1 pathway. This pathway is potently activated by resistance exercise and amino acids, but the stimulatory role of individual amino acids in human skeletal muscle is unclear. Muscle adaptations in response to endurance exercise are largely dependent on the PGC-1 α pathway, which regulates mitochondrial biogenesis. Given the different training adaptations after resistance and endurance exercise, it has been suggested that these exercise modalities may be incompatible when combined. Such potential interference could be exerted at the molecular level between the pathways responsible for each adaptive response. AMPK, an enzyme usually activated by endurance exercise and, when pharmacologically activated in cell culture and rodent models, has been shown to inhibit mTORC1 and protein synthesis. However, it is not known if activation of AMPK by endurance exercise inhibits resistance exercise induced signaling through the mTORC1 pathway in human skeletal muscle.

    Thus, the main objective of this thesis was to examine the molecular mechanisms regulating protein synthesis in response to amino acids and various modes of exercise in human skeletal muscle.

    In study I, the role of BCAAs in stimulating the mTORC1 pathway was examined in both resting and exercising muscle. BCAA increased mTORC1 activity, as assessed by S6K1 phosphorylation, in both resting and exercising muscle, but more so when exercise and BCAA were combined. In study II, the effect of leucine was compared to that of essential amino acids with or without leucine. It was found that when leucine was combined with the remaining essential amino acids, S6K1 phosphorylation was more pronounced than when leucine was provided alone. Furthermore, when leucine was removed from the essential amino acids, the effect was equal to that of placebo. In study III, the impact of endurance exercise on resistance exercise induced mTORC1 signaling was examined. When performed after resistance exercise, endurance exercise did not inhibit S6K1 phosphorylation compared to when single mode resistance exercise was performed. In study IV, performance of high intensity endurance exercise prior to resistance exercise did not inhibit S6K1 phosphorylation compared to single mode resistance exercise, despite prior activation of AMPK.

    In conclusion, amino acids and resistance exercise activate mTORC1 signaling, as assessed by S6K1 phosphorylation, in a synergistic manner. Leucine is crucial in mediating the amino acid response, however, additional amino acids appear to be required to induce a maximal response downstream of mTORC1. Activation of the mTORC1 pathway in response to heavy resistance exercise is robust and this activation does not appear to be inhibited by prior or by subsequent endurance exercise. As such, these results do not lend support to the existence of molecular interference when resistance and endurance exercise are combined acutely.

  • 14.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Influence of supplementation with branched-chain amino acids in combination with resistance exercise on p70S6 kinase phosphorylation in resting and exercising human skeletal muscle.2010In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 200, no 3, p. 237-48Article in journal (Refereed)
    Abstract [en]

    AIM: Skeletal muscle growth is thought to be regulated by the mammalian target of rapamycin (mTOR) pathway, which can be activated by resistance exercise and branched-chain amino acids (BCAA). The major aim of the present study was to distinguish between the influence of resistance exercise and BCAA on key enzymes considered to be involved in the regulation of protein synthesis, including p70(S6) kinase (p70(S6k)). METHODS: Nine healthy subjects (four men and five women) performed unilateral resistance exercise on two occasions separated by 1 month. Subjects were randomly supplied either a mixture of BCAA or flavoured water. Muscle biopsies were taken from both resting and exercising muscle before, after and 1 h after exercise. RESULTS: Phosphorylation of Akt was unaltered by either resistance exercise and/or BCAA supplementation whereas mTOR phosphorylation was enhanced (P<0.05) to a similar extent in both exercising and resting muscle following exercise in the absence (70-90%) and presence of BCAA supplementation (80-130%). Phosphorylation of p70(S6k) was unaffected by resistance exercise alone; however, BCAA intake increased (P<0.05) this phosphorylation in both legs following exercise. In resting muscle, a 5- and 16-fold increase in p70(S6k) was observed immediately after and 1 h after exercise, respectively, as compared to 11- and 30-fold increases in the exercising muscle. Phosphorylation of eukaryotic elongation factor 2 was attenuated 1 h after exercise (P<0.05) in both resting (10-40%) and exercising muscle (30-50%) under both conditions. CONCLUSION: The present findings indicate that resistance exercise and BCAA exert both separate and combined effects on the p70(S6k) phosphorylation in an Akt-independent manner.

  • 15.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH.
    Holmberg, Hans-Christer
    Mittuniversitetet.
    Rooyackers, Olav
    Karolinska universitetssjukhuset, Huddinge.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Is leucine induced p70S6 kinase phosphorylation following resistance exercise dependent on elevated phenylalanine levels in human skeletal muscle?2010Conference paper (Other academic)
  • 16.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand'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 and Mats Börjesson's research group.
    Rooyackers, O
    Holmberg, HC
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Leucine does not affect mTORC1 assembly but is required for maximal S6K1 activity in human skeletal muscle following resistance exerciseManuscript (preprint) (Other academic)
  • 17.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Hamilton, D Lee
    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.
    Rooyackers, Olav
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Leucine does not affect mechanistic target of rapamycin complex 1 assembly but is required for maximal ribosomal protein s6 kinase 1 activity in human skeletal muscle following resistance exercise.2015In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 29, no 10, p. 4358-4373Article in journal (Refereed)
    Abstract [en]

    We examined how the stimulatory effect of leucine on the mechanistic target of rapamycin complex 1 (mTORC1) pathway is affected by the presence of the remaining essential amino acids. Nine male subjects performed resistance exercise on 4 occasions and were randomly supplied essential amino acids (EAAs) with or without leucine (EAA-Leu), leucine alone, or flavored water (placebo; control). Muscle biopsies were taken from the vastus lateralis before and 60 and 90 min after exercise. Biopsies were analyzed for protein phosphorylation, kinase activity, protein-protein interactions, amino acid concentrations, and tracer incorporation. Leucine alone stimulated ribosomal protein s6 kinase 1 (S6K1) phosphorylation ∼280% more than placebo and EAA-Leu after exercise. Moreover, this response was enhanced by 60-75% after intake of EAAs compared with that of leucine alone (P < 0.05). Kinase activity of S6K1 reflected that of S6K1 phosphorylation; 60 min after exercise, the activity was elevated 3.3- and 4.2-fold with intake of leucine alone and with EAAs, respectively (P < 0.05). The interaction between mammalian target of rapamycin and regulatory-associated protein of mammalian target of rapamycin was unaltered in response to both resistance exercise and amino acid provision. Leucine alone stimulates mTORC1 signaling, although this response is enhanced by other EAA and does not appear to be caused by alterations in mTORC1 assembly.-Apró, W., Moberg, M., Hamilton, D. L., Ekblom, B., Rooyackers, O., Holmberg, H.-C., Blomstrand, E. Leucine does not affect mechanistic target of rapamycin complex 1 assembly but is required for maximal ribosomal protein s6 kinase 1 activity in human skeletal muscle following resistance exercise.

  • 18.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Hamilton, L.
    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.
    van Hall, G.
    Holmberg, HC
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Resistance exercise induced S6K1 kinase activity is not inhibited in human skeletal muscle despite prior activation of AMPK by high intensity interval cycling.2015In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 308, no 6, p. E470-E481Article in journal (Refereed)
    Abstract [en]

    Combining endurance and strength training in the same session has been reported to reduce the anabolic response to the latter form of exercise. The underlying mechanism, based primarily on results from rodent muscle, is proposed to involve AMPK-dependent inhibition of mTORC1 signaling. This hypothesis was tested in eight trained male subjects who in a randomized order performed either resistance exercise only (R) or interval cycling followed by resistance exercise (ER). Biopsies taken from the vastus lateralis before and after endurance exercise and repeatedly after resistance exercise were assessed for glycogen content, kinase activity, protein phosphorylation and gene expression. Mixed muscle fractional synthetic rate was measured at rest and during 3h of recovery using the stable isotope technique. In ER, AMPK activity was elevated immediately after both endurance and resistance exercise (~90%, P<0.05) but was unchanged in R. Thr389 phosphorylation of S6K1 was increased several-fold immediately after exercise (P<0.05) in both trials and increased further throughout recovery. After 90 and 180 min recovery, S6K1 activity was elevated (~55% and ~110%, respectively, P<0.05) and eEF2 phosphorylation was reduced (~55%, P<0.05) with no difference between trials. In contrast, markers for protein catabolism were differently influenced by the two modes of exercise; ER induced a significant increase in gene and protein expression of MuRF1 (P<0.05), which was not observed following R exercise only. In conclusion, cycling-induced elevation in AMPK activity does not inhibit mTORC1 signaling after subsequent resistance exercise, but may instead interfere with the hypertrophic response by influencing key components in protein breakdown.

  • 19.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Moberg, Marcus
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Amino Acid-induced S6K1 Activity In Human Skeletal Muscle Is Mediated By Increased mTor/Rheb Interaction: 128 June 1, 11: 15 AM - 11: 30 AM.2016In: Medicine And Science In Sports And Exercise 2016 May; Vol. 48 (5S Suppl 1), pp. 17., 2016, Vol. 48, no 5S Suppl 1, p. 17-17Conference paper (Refereed)
    Abstract [en]

    Cell culture studies have shown that amino acids activate mTORC1 signaling by increasing the interaction between mTOR and its essential activator Rheb. However, the existence of this mechanism in human skeletal muscle remains to be determined.

    PURPOSE: To determine if increased mTORC1 signaling in response to amino acids in human skeletal muscle is due to an increased interaction between mTOR and Rheb.

    METHODS: Eight well trained men performed resistance exercise on two separate occasions. In connection with the exercise, subjects were supplemented with flavored water (Pla) and essential amino acids (EAA) in a double-blind, randomized cross-over design. Muscle biopsies were taken in the vastus lateralis muscle before, immediately after and 90 and 180 min post exercise. Activity of the mTORC1 pathway was assessed by a radiolabeled in-vitro kinase assay for its immediate downstream target S6K1. Protein-protein interactions were determined by western blot following co-immunoprecipitation of mTOR with Rheb. Co-immunoprecipitation was performed on pooled muscle samples from three of the eight subjects.

    RESULTS: Activity of S6K1 remained unchanged immediately after exercise in both trials. However, at 90 min post exercise, S6K1 activity increased by approximately 2- and 8-fold (p<0.05) from baseline the Pla and EAA trials, respectively. At the 180 min time point, S6K1 activity remained elevated in both trials being approx. 3-fold higher in the Pla trial and 5-fold higher (p<0.05) in the EAA trial. The fold-change in mTOR and Rheb interaction largely resembled the activity pattern of S6K1 in both trials; in the Pla trial the fold-change was 0.9, 1.3 and 1.4 while in the EAA trial the fold-change was 1.6, 2.9 and 1.9 immediately after, 90 min after and 180 min after exercise, respectively.

    CONCLUSIONS: The large increase in S6K1 activity following EAA intake appears to be mediated by an increased interaction between mTOR and its proximal activator Rheb. This is the first time this mechanism has been demonstrated in human skeletal muscle.

  • 20.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Wang, Li
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Endurance Exercise Does Not Impair mTOR Signalling After Resistance Exercise: D-58 Thematic Poster - Skeletal Muscle Cell Signaling: JUNE 2, 2011 3:15 PM - 5:15 PM: ROOM: 3042011In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 43, no 5, p. 52-Article in journal (Other academic)
    Abstract [en]

    Resistance exercise is known to stimulate muscle hypertrophy and this effect is mainly mediated by the mammalian target of rapamycin (mTOR) pathway. In contrast, endurance exercise results in a divergent phenotypic response which to a large extent is mediated by adenosine monophosphate-activated protein kinase (AMPK). Research indicates that molecular interference may exist, possibly through an inhibitory effect on mTOR signalling by AMPK, when these two modes of exercise are combined.

    PURPOSE: To investigate the impact of subsequent endurance exercise on resistance exercise induced mTOR signalling.

    METHODS: In a randomized and cross-over fashion, ten male subjects performed either heavy resistance exercise (R) or heavy resistance exercise followed by endurance exercise (RE) on two separate occasions. The R protocol consisted of thirteen sets of leg press exercise with 3 minutes of recovery allowed between each set. In the RE session, resistance exercise was followed by 15 minutes recovery after which 30 min of cycling was initiated at an intensity equal to 70 % of the subjects' maximal oxygen consumption. Muscle biopsies were collected before, 1 and 3 hours after resistance exercise in both trials. Samples were analyzed for several signalling proteins in the mTOR pathway using western blot technique.

    RESULTS: Phosphorylation of mTOR increased approx. twofold at 1 h post resistance exercise and remained elevated at the 3 h time point (p< 0.01) with no difference between the two trials. Phosphorylation of p70S6k, a downstream target of mTOR, was increased about 6-and18-fold at 1 h and 3 h post resistance exercise (p< 0.01). There was no difference in p70S6k phosphorylation at any time point between the two trials. Phosphorylation of the eukaryotic elongation factor eEF2 was decreased 3- to 4-fold at both time points post resistance exercise (p< 0.01) with no difference between trials. Phosphorylation of AMPK was unchanged at the 1 h time point but decreased approximately 30 % from pre-exercise values in both trials at 3 h post resistance exercise (p< 0.01).

    CONCLUSIONS: The signalling response following heavy resistance exercise is not blunted by subsequent endurance exercise. Supported by the Swedish National Centre for Research in Sports.

  • 21.
    Apró, William
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Wang, Li
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Pontén, Marjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Resistance exercise induced mTORC1 signaling is not impaired by subsequent endurance exercise in human skeletal muscle.2013In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 305, no 1, p. E22-32Article in journal (Refereed)
    Abstract [en]

    The current dogma is that the muscle adaptation to resistance exercise is blunted when combined with endurance exercise. The suggested mechanism (based on rodent experiments) is that activation of adenosine monophosphate-activated protein kinase (AMPK) during endurance exercise impairs muscle growth through inhibition of the mechanistic target of rapamycin complex 1 (mTORC1). The purpose of this study was to investigate potential interference of endurance training on the signaling pathway of resistance training [mTORC1 phosphorylation of ribosomal protein S6 kinase 1 (S6K1)] in human muscle. Ten healthy and moderately trained male subjects performed on two separate occasions either acute high-intensity and high-volume resistance exercise (leg press, R) or R followed by 30 min of cycling (RE). Muscle biopsies were collected before and 1 and 3 h post resistance exercise. Phosphorylation of mTOR (Ser(2448)) increased 2-fold (P < 0.05) and that of S6K1 (Thr(389)) 14-fold (P < 0.05), with no difference between R and RE. Phosphorylation of eukaryotic elongation factor 2 (eEF2, Thr(56)) was reduced ∼70% during recovery in both trials (P < 0.05). An interesting finding was that phosphorylation of AMPK (Thr(172)) and acetyl-CoA carboxylase (ACC, Ser(79)) decreased ∼30% and ∼50%, respectively, 3 h postexercise (P < 0.05). Proliferator-activated receptor-γ coactivator-1 (PGC-1α) mRNA increased more after RE (6.5-fold) than after R (4-fold) (RE vs. R: P < 0.01) and was the only gene expressed differently between trials. These data show that the signaling of muscle growth through the mTORC1-S6K1 axis after heavy resistance exercise is not inhibited by subsequent endurance exercise. It is also suggested that prior activation of mTORC1 signaling may repress subsequent phosphorylation of AMPK.

  • 22.
    Badland, Hannah
    et al.
    Auckland University of Technology, New Zealand.
    Oliver, Melody
    Auckland University of Technology, New Zealand.
    Duncan, Mitch
    Central Queensland University, Australia.
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, The Research Unit for Movement, Health and Environment.
    Measuring children´s independent mobility: Comparing objective and self-report approaches2011In: Children's Geographies, ISSN 1473-3285, E-ISSN 1473-3277, Vol. 9, no 2, p. 263-271Article in journal (Refereed)
  • 23. Bakkman, Linda
    et al.
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Holmberg, H-C
    Tonkonogi, Michail
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Quantitative and qualitative adaptation of human skeletal muscle mitochondria to hypoxic compared with normoxic training at the same relative work rate.2007In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 190, no 3, p. 243-51Article in journal (Refereed)
    Abstract [en]

    AIM: To investigate if training during hypoxia (H) improves the adaptation of muscle oxidative function compared with normoxic (N) training performed at the same relative intensity. METHOD: Eight untrained volunteers performed one-legged cycle training during 4 weeks in a low-pressure chamber. One leg was trained under N conditions and the other leg under hypobaric hypoxia (526 mmHg) at the same relative intensity as during N (65% of maximal power output, W(max)). Muscle biopsies were taken from vastus lateralis before and after the training period. Muscle samples were analysed for the activities of oxidative enzymes [citrate synthase (CS) and cytochrome c oxidase (COX)] and mitochondrial respiratory function. RESULTS: W(max) increased with more than 30% over the training period during both N and H. CS activity increased significantly after training during N conditions (+20.8%, P < 0.05) but remained unchanged after H training (+4.5%, ns) with a significant difference between conditions (P < 0.05 H vs. N). COX activity was not significantly changed by training and was not different between exercise conditions [+14.6 (N) vs. -2.3% (H), ns]. Maximal ADP stimulated respiration (state 3) expressed per weight of muscle tended to increase after N (+31.2%, P < 0.08) but not after H training (+3.2%, ns). No changes were found in state four respiration, respiratory control index, P/O ratio, mitochondrial Ca(2+) resistance and apparent Km for oxygen. CONCLUSION: The training-induced increase in muscle oxidative function observed during N was abolished during H. Altitude training may thus be disadvantageous for adaptation of muscle oxidative function.

  • 24. Balsom, Paul D
    et al.
    Gaitanos, G C
    Söderlund, Karin
    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.
    High-intensity exercise and muscle glycogen availability in humans.1999In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 165, no 4, p. 337-45Article in journal (Refereed)
    Abstract [en]

    This study investigated the effects of muscle glycogen availability on performance and selected physiological and metabolic responses during high-intensity intermittent exercise. Seven male subjects completed a regimen of exercise and dietary intake (48 h) to either lower and keep low (LOW-CHO) or lower and then increase (HIGH-CHO) muscle glycogen stores, on two separate occasions at least a week apart. On each occasion the subjects completed a short-term (<10 min) and prolonged (>30 min) intermittent exercise (IEX) protocol, 24 h apart, which consisted of 6-s bouts of high-intensity exercise performed at 30-s intervals on a cycle ergometer. Glycogen concentration (mean +/- SEM) in m. vastus lateralis before both IEx(short) and IEx(long) was significantly lower following LOW-CHO [180 (14), 181 (17) mmol kg (dw)(-1)] compared with HIGH-CHO [397 (35), 540 (25) mmol kg (dw)(-1)]. In both IEx(short) and IEx(long), significantly less work was performed following LOW-CHO compared with HIGH-CHO. In IEx(long), the number of exercise bouts that could be completed at a pre-determined target exercise intensity increased by 265% from 111 (14) following LOW-CHO to 294 (29) following HIGH-CHO (P < 0.05). At the point of fatigue in IEx(long), glycogen concentration was significantly lower with the LOW-CHO compared with HIGH-CHO [58 (25) vs. 181 (46) mmol kg (dw)(-1), respectively]. The plasma concentrations of adrenaline and nor-adrenaline (in IEx(short) and IEx(long)), and FFAand glycerol (in IEx(long)), increased several-fold above resting values with both experimental conditions. Oxygen uptake during the exercise periods in IEx(long), approached 70% of Vo2max. These results suggest that muscle glycogen availability can affect performance during both short-term and more prolonged high-intensity intermittent exercise and that with repeated exercise periods as short as 6 s, there can be a relatively high aerobic contribution.

  • 25. Balsom, Paul
    et al.
    Seger, Jan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Sjödin, Bertil
    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. Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Maximal-Intensity Intermittent Exercise: Effect of Recovery Duration1992In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 13, no 7, p. 528-533Article in journal (Refereed)
    Abstract [en]

    Seven male subjects performed 15 x 40m sprints, on three occasions, with rest periods of either 120 s (R120), 60 s (R60) or 30 s (R30) between each sprint. Sprint times were recorded with four photo cells placed at 0, 15, 30 and 40 m. The performance data indicated that whereas running speed over the last 10 m of each sprint decreased in all three protocols (after 11 sprints in R120, 7 sprints in R60 and 3 sprints in R30), performance during the initial acceleration period from 0-15 m was only affected with the shortest rest periods increasing from (mean +/- SEM) 2.58 +/- .03 (sprint 1) to 2.78 +/- .04 s (spring 15) (p < .05). Post-exercise blood lactate concentration was not significantly different in R120 (12.1 +/- 1.3 mmol.l-1) and R60 (13.9 +/- 1.2 mmol.l-1), but a higher concentration was found in R30 (17.2 +/- .7 mmol.l-1) (p < .05). After 6 sprints there was no significant difference in blood lactate concentration with the different recovery durations, however, there were significant differences in sprint times at this point, suggesting that blood lactate is a poor predictor of performance during this type of exercise. Although the work bouts could be classified primarily as anaerobic exercise, oxygen uptake measured during rest periods increased to 52, 57 and 66% of maximum oxygen uptake in R120, R60 and R30, respectively. Evidence of adenine nucleotide degradation was provided by plasma hypoxanthine and uric acid concentrations elevated post-exercise in all three protocols. Post-exercise uric acid concentration was not significantly affected by recovery duration.(ABSTRACT TRUNCATED AT 250 WORDS)

  • 26.
    Bendrik, R., Jr.
    et al.
    Uppsala Univ, Deparment Publ Hlth & Caring Sci, Uppsala, Sweden.;Uppsala Univ, Ctr Res & Dev, Gavle, Sweden.;Reg Gavleborg, Gavle, Sweden..
    Kallings, Lena
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Björn Ekblom's research group. Uppsala Univ, Deparment Publ Hlth & Caring Sci, Uppsala, Sweden..
    Broms, K., Sr.
    Uppsala Univ, Deparment Publ Hlth & Caring Sci, Uppsala, Sweden.;Uppsala Univ, Ctr Res & Dev, Gavle, Sweden.;Reg Gavleborg, Gavle, Sweden..
    Emtner, M., Sr.
    Uppsala Univ, Dept Neurosci, Uppsala, Sweden..
    MAXIMAL STEP-UP TEST A NEW FUNCTIONAL TEST IN HIP OR KNEE OSTEOARTHRITIS2016In: Osteoarthritis and Cartilage, ISSN 1522-9653, Vol. 24, no S1, p. S471-S471Article in journal (Refereed)
  • 27.
    Berg, Ulrika
    et al.
    Astrid Lindgrens barnsjukhus.
    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.
    Rekommendationer om fysisk aktivitet för barn och ungdomar2016In: FYSS 2017: fysisk aktivitet i sjukdomsprevention och sjukdomsbehandling, Läkartidningen förlag , 2016, p. 98-113Chapter in book (Other academic)
    Abstract [sv]

    Sammanfattning

    Fysisk aktivitet ger fysiska och mentala hälsovinster hos barn och ungdomar.

    Mognads- och tillväxtprocesserna hos barn och ungdomar påverkar en rad fysiska, mentala och sociala kapaciteter och förmågor. Vid rekommendation av fysisk aktivitet bör hänsyn tas till detta och individuella intressen.

    Alla barn och ungdomar mellan 6 och 17 år rekommenderas minst 60 minuters daglig fysisk aktivitet av främst aerob karaktär. Muskelstärkande och skelettstärkande aktiviteter bör ingå tre gånger i veckan. Hos barn från 0–5 år ska daglig fysisk aktivitet uppmuntras och underlättas.

    Barn och ungdomar som inte kan nå upp till rekommendationerna på grund av sjukdom eller funktionsnedsättning bör vara så aktiva som tillståndet medger.

    Individuella råd för anpassad regelbunden fysisk aktivitet bör ges.

    Barn och ungdomar med övervikt och fetma kan uppnå positiva hälsoeffekter av fysisk aktivitet avseende till exempel blodfetter och insulinkänslighet även om vikten är oförändrad. Konditionshöjande fysisk aktivitet har tydligast effekt, och i kombination med kostförändringar är effekterna större.

    Hos barn och ungdomar med astma bör en noggrann analys av ansträngningsutlösta besvär göras. Astman ska vara välreglerad och anpassad information och kunskap ska ges för att trygga den unge och främja fysisk aktivitet.

    Fysisk aktivitet utgör en del av behandlingen vid depression hos barn och ungdomar.

    Barn och ungdomars hälsa tycks kunna påverkas negativt av långvarigt stillasittande. För närvarande finns dock inte tillräckligt med vetenskapligt stöd för att ge en evidensbaserad rekommendation angående begränsning av stillasittande i den här åldersgruppen.

  • 28.
    Berg, Ulrika
    et al.
    Astrid Lindgrens barnsjukhus.
    Ekblom, Örjan
    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.
    Rekommendationer om fysisk aktivitet för barn och ungdomar2015In: FYSS 2015, Stockholm: Yrkesföreningar för Fysisk Aktivitet (YFA) , 2015Chapter in book (Other (popular science, discussion, etc.))
    Abstract [sv]

    En rimlig fråga är varför barn och unga är speciella när det gäller hälsoeffekter av fysisk aktivitet. Många av de påvisade och kända effekterna av fysisk aktivitet är likartade oavsett ålder, men i vissa fall finns det anledning att lyfta fram vad som är specifikt för barn och unga.

    Mognads- och tillväxtprocesserna, som i princip pågår fram till cirka 18–20 års ålder, är ofta orsaken till de skillnader som finns. En rad kapaciteter och förmågor, till exempel syreupptagningsförmåga, muskelstyrka, koordination och motorik samt mentala aspekter utvecklas över tid. En konsekvens av detta är att det är svårt att med precision utvärdera effekter av träning hos en ung individ, och att på ett korrekt och meningsfullt sätt särskilja dessa från mognad och tillväxt. En annan faktor är ökande kroppsstorlek, vilken medför att gränser för övervikt och fetma varierar mellan könen och med ålder upp till cirka 18 år. Att på ett korrekt sätt värdera effekter av insatser mot övervikt hos en växande individ kräver särskilda överväganden.

  • 29.
    Berg, Ulrika
    et al.
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Enqvist, Jonas K
    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.
    Carlsson-Skwirut, Christine
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Sundberg, Carl-Johan
    Institutionen för Fysiologi och Farmakologi, Karolinska institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bang, Peter
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Lack of sex differences in the IGF-IGFBP response to ultra endurance exercise.2008In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 18, no 6, p. 706-714Article in journal (Refereed)
    Abstract [en]

    The insulin-like growth factor (IGF)-IGF binding proteins (BP) and the pituitary-gonadal axes were investigated during ultra endurance exercise in 16 endurance-trained athletes (seven women). Median duration of the race was 6.3 days. Although food and drink were ad libitum, energy balance was negative. Blood samples were drawn before (PRE), at the end of (END) and 24 h after (POST24h) the race. Serum concentrations of total IGF-I (t-IGF-I) and free IGF-I (f-IGF-I) decreased by 33 (SD 38)% and 54 (19)%, respectively. The decrease in t-IGF-I appeared to be associated to the total energy deficit during the race. At END, the IGFBP-3 fragmentation and IGFBP-1 were increased but these changes did not predict changes in f-IGF-I. An increase in POST24h IGFBP-2 levels in women was the only sex difference. Testosterone was decreased by 67 (12)% in the men and estradiol became undetectable in the women without any detectable increase in LH and/or FSH. In conclusion ultra endurance exercise results in similar IGF-IGFBP responses in men and women reflecting a catabolic state. IGFBP-2 was the only exception, with increased levels in women after exercise. A concomitant decrease in gonadal hormones was not related to endocrine changes in the IGF-IGFBP axis but may be related to local changes in IGF-I expression.

  • 30.
    Berg, Ulrika
    et al.
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Enqvist, Jonas
    Swedish School of Sport and Health Sciences, GIH.
    Mattsson, C. Mikael
    Swedish School of Sport and Health Sciences, GIH.
    Carlsson-Skwirut, Christine
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    Sundberg, Carl-Johan
    Institutionen för Fysiologi och Farmakologi (FyFa), Karolinska Institutet.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Bang, Peter
    Institutionen för Kvinnors och Barns Hälsa (KBH), Karolinska Institutet.
    The IGF- IGFBP system during ultra-endurance exercise in men and women.2007In: Gordon Research Conference – IGF in physiology & disease, Ventura, CA, USA., 2007Conference paper (Other academic)
  • 31. Bergh, U
    et al.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Åstrand, PO
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences.
    Maximal oxygen uptake "classical" versus "contemporary" viewpoints.2000In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 32, no 1, p. 85-8Article in journal (Refereed)
    Abstract [en]

    In two articles Timothy Noakes proposes a new physiological model in which skeletal muscle recruitment is regulated by a central "govenor," specifically to prevent the development of a progressive myocardial ischemia that would precede the development of skeletal muscle anaerobiosis during maximal exercise. In this rebuttal to the Noakes' papers, we argue that Noakes has ignored data supporting the existing hypothesis that under normal conditions cardiac output is limiting maximal aerobic power during dynamic exercise engaging large muscle groups.

  • 32. Berglund, B
    et al.
    Ekblom, Björn
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Ekblom, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Björn Ekblom's research group.
    Berglund, L
    Kallner, A
    Reinebo, P
    Lindeberg, S
    The Swedish Blood Pass project.2007In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 17, no 3, p. 292-7Article in journal (Refereed)
    Abstract [en]

    Manipulation of the blood's oxygen carrying capacity (CaO(2)) through reinfusion of red blood cells, injections of recombinant erythropoietin or by other means results in an increased maximal oxygen uptake and concomitantly enhanced endurance performance. Therefore, there is a need to establish a system--"A Blood Pass"--through which such illegal and unethical methods can be detected. Venous blood samples were taken under standardized conditions from 47 male and female Swedish national and international elite endurance athletes four times during the athletic year of the individual sport (beginning and end of the preparation period and at the beginning and during peak performance in the competition period). In these samples, different hematological values were determined. ON(hes) and OFF(hre) values were calculated according to the formula of Gore et al. A questionnaire regarding training at altitude, alcohol use and other important factors for hematological status was answered by the athletes. There were some individual variations comparing hematological values obtained at different times of the athletic year or at the same time in the athletic year but in different years. However, the median values of all individual hematological, ON(hes) and OFF(hre), values taken at the beginning and the end of the preparation or at the beginning and the end of the competition period, respectively, as well as median values for the preparation and competition periods in the respective sport, were all within the 95% confidence limit (CI) of each comparison. It must be mentioned that there was no gender difference in this respect. This study shows that even if there are some individual variations in different hematological values between different sampling times in the athletic year, median values of important hematological factors are stable over time. It must be emphasized that for each blood sample, the 95% CI in each athlete will be increasingly narrower. The conclusion is that there is a physiological basis for establishing an individual-based "Blood Pass" system, mainly for athletes competing at the international level. On indications of manipulations of hemoglobin concentration and red cell mass by deviations from established "Blood Pass" data, more specific methods can be applied.

  • 33.
    Bergström, Göran
    et al.
    Göteborgs universitet.
    Börjesson, Mats
    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.
    Schmidt, Caroline
    Göteborgs universitet.
    Self-efficacy regarding physical activity is superior to self-assessed activity level, in long-term prediction of cardiovascular events in middle-aged men2015In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 15, article id 820Article in journal (Refereed)
    Abstract [en]

    Background

    Self-efficacy has been determined to be a strong predictor of who will engage in physical activity. We aimed to evaluate the associations between self-efficacy to perform physical activity, self-reported leisure-time physical activity and cardiovascular events in a population-based cohort of middle-aged Swedish men with no previous cardiovascular disease, or treatment with cardiovascular drugs.

    Methods

    Analyses are based on 377 men randomly selected and stratified for weight and insulin sensitivity from a population sample of 58-year-old men (n = 1728) and who had answered a question about their competence to perform exercise (as an assessment of physical self-efficacy). The Saltin-Grimby Physical Activity Level Scale was used to assess self-reported levels of leisure-time physical activity. Cardiovascular events were recorded during 13-years of follow-up.

    Results

    The group with poor self-efficacy to perform physical activity had a significantly higher incidence of cardiovascular events compared with the group with good physical self-efficacy (32.1 % vs 17.1 %, p < 0.01). Multivariate analyses showed that poor physical self-efficacy was associated with an increased relative risk of 2.0 (95 % CI 1.2 to 3.0), of having a cardiovascular event during follow-up also after adjustments for co-variates such as waist to hip ratio, heart rate, fasting plasma glucose, serum triglycerides, systolic blood pressure, apoB/apoA-I ratio and leisure-time physical activity.

    Conclusion

    Self-efficacy to perform physical activity was strongly and independently associated with cardiovascular events and was superior to self-assessed physical activity in predicting cardiovascular events during 13-years of follow-up in a group of middle-aged men, without known CVD or treatment with cardiovascular drugs.

  • 34. Bergström, Ylva
    et al.
    Schantz, Peter
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, The Research Unit for Movement, Health and Environment.
    Brunnsvikenguiden1992In: Hagabladet - en tidning för natur och kultur vid Haga-Brunnsviken, no 4-5, p. 3-8Article in journal (Other (popular science, discussion, etc.))
  • 35.
    Bermon, Stephane
    et al.
    Monaco Inst Sports Med & Surg, Monaco.
    Castell, Lindy M
    Univ Oxford, Green Templeton Coll, Oxford, England.
    Calder, Philip C
    Bishop, Nicolette C
    Univ Southampton, Fac Med, Human Dev & Hlth Acad Unit, Southampton, Hants, England.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Mooren, Frank C
    Justus Liebig Univ, Dept Sports Med, Giessen, Germany.
    Krüger, Karsten
    Justus Liebig Univ, Dept Sports Med, Giessen, Germany.
    Kavazis, Andreas N
    Auburn Univ, Sch Kinesiol, Auburn, AL 36849 USA.
    Quindry, John C
    Univ Montana, Hlth & Human Performance, Missoula, MT 59812 USA.
    Senchina, David S
    Drake Univ, Dept Biol, Kinesiol Program, Des Moines, IA 50311 USA.
    Nieman, David C
    Appalachian State Univ, Human Performance Lab, North Carolina Res Campus, Kannapolis, NC USA.
    Gleeson, Michael
    Univ Loughborough, Sch Sport Exercise & Hlth Sci, Loughborough, Leics, England.
    Pyne, David B
    Australian Inst Sport, Bruce, Australia.
    Kitic, Cecilia M
    Univ Tasmania, Sch Hlth Sci, Sport Performance Optimisat Res Team, Launceston, Tas, Australia.
    Close, Graeme L
    Liverpool John Moores Univ, Res Inst Sport & Exercise Sci, Liverpool, Merseyside, England.
    Larson-Meyer, D Enette
    Univ Wyoming, Dept Family & Consumer Sci, Nutr & Exercise Lab, Laramie, WY 82071 USA.
    Marcos, Ascension
    CSIC, Spanish Natl Res Council, Inst Food Sci Technol & Nutr ICTAN, Madrid, Spain.
    Meydani, Simin N
    Tufts Univ, Jean Mayer USDA Human Nutr Res Ctr Aging, Boston, MA 02111 USA.
    Wu, Dayong
    Tufts Univ, Jean Mayer USDA Human Nutr Res Ctr Aging, Boston, MA 02111 USA.
    Walsh, Neil P
    Bangor Univ, Sch Sport Hlth & Exercise Sci, Bangor, Gwynedd, Wales.
    Nagatomi, Ryochi
    Tohoku Univ, Grad Sch Biomed Engn, Lab Hlth & Sports Sci, Sendai, Miyagi, Japan.
    Consensus Statement Immunonutrition and Exercise.2017In: Exercise immunology review, ISSN 1077-5552, Vol. 23, p. 8-50Article, review/survey (Refereed)
    Abstract [en]

    In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research.

  • 36.
    Berthelson, 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
    Institutionen för Fysiologi och Farmakologi, Karolinska Instititutet.
    Andersson, Eva
    Swedish School of Sport and Health Sciences, GIH.
    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 and starvation induced insulin resistance2012In: Medicine & Science In Sports & Exercise, 2012, S498 Vol. 44 No. 5 Supplement. 2661., 2012, p. 2661-Conference paper (Other academic)
    Abstract [en]

    It is well known that starvation causes insulin resistance. The mechanism is unclear but may relate disturbances in lipid metabolism i.e. incomplete mitochondrial FA oxidation and/or accumulation of lipid intermediates. Exercise results in increased substrate oxidation and may thus remove interfering lipid metabolites and reverse starvation-induced insulin resistance. However, the effect of acute exercise and starvation on insulin sensitivity is not known.

    Purpose: The aim of this study was to investigate the effect of exercise on starvation-induced insulin resistance and to elucidate potential mechanisms.

    Methods: Nine healthy lean subjects underwent 84h starvation on two occasions separated by at least 2 weeks. The starvation period was followed by either exercise (EX; 5x10 min intervals with 2-4 min rest, starting at 70 %VO2 max) or an equal period of rest (NE). Before and after the starvation period (3h after exercise/rest) subjects were investigated with muscle biopsies, bloo samples and an intravenous glucose tolerance test. Muscle samples were used for measurement of mitochondrial respiration in permeabilized muscle fibers (Oroboros oxygraph), glycogen content and activation of signaling proteins.

    Results: Insulin sensitivity was significantly higher in the EX group compared to the NE group (p<0.05). After starvation mitochondrial respiration was lower in both groups with complex I substrates whereas respiration with complex I+II substrates was higher in EX (p<0.05 vs. basal and NE). Muscle glycogen was decreased to 73% (NE) and 31% (EX) of the basal values. The EX group had a significant increased activation of AS160. Plasma FA increased 3-4 fold to 1.39±0.32(NE) and 1.80±0.49 (EX) (mmol/l) after starvation and plasma beta-hydroxybutyrate increased about 50-fold to 6.43±2.01(NE) and 7.12±1.59 (EX)(mmol/l).

    Conclusion: Acute exercise reverses starvation-induced insulin resistance. Plasma FA and BOH were increased to similar extent after NE and EX and cannot explain the changes in insulin sensitivity. However, an increased substrate oxidation together with the observed increased capacity for mitochondrial FA oxidation after EX may be involved in the activation of AS160 and the reversal of starvation-induced insulin resistance.

  • 37. Bishop, David J
    et al.
    Thomas, Claire
    Moore-Morris, Tom
    Tonkonogi, Michail
    Sahlin, Kent
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Research group for Mitokondriell funktion och metabolisk kontroll.
    Mercier, Jacques
    Sodium bicarbonate ingestion prior to training improves mitochondrial adaptations in rats.2010In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 299, no 2, p. E225-33Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis that reducing hydrogen ion accumulation during training would result in greater improvements in muscle oxidative capacity and time to exhaustion (TTE). Male Wistar rats were randomly assigned to one of three groups (CON, PLA, and BIC). CON served as a sedentary control, whereas PLA ingested water and BIC ingested sodium bicarbonate 30 min prior to every training session. Training consisted of seven to twelve 2-min intervals performed five times/wk for 5 wk. Following training, TTE was significantly greater in BIC (81.2 +/- 24.7 min) compared with PLA (53.5 +/- 30.4 min), and TTE for both groups was greater than CON (6.5 +/- 2.5 min). Fiber respiration was determined in the soleus (SOL) and extensor digitorum longus (EDL), with either pyruvate (Pyr) or palmitoyl carnitine (PC) as substrates. Compared with CON (14.3 +/- 2.6 nmol O(2).min(-1).mg dry wt(-1)), there was a significantly greater SOL-Pyr state 3 respiration in both PLA (19.6 +/- 3.0 nmol O(2).min(-1).mg dry wt(-1)) and BIC (24.4 +/- 2.8 nmol O(2).min(-1).mg dry wt(-1)), with a significantly greater value in BIC. However, state 3 respiration was significantly lower in the EDL from both trained groups compared with CON. These differences remained significant in the SOL, but not the EDL, when respiration was corrected for citrate synthase activity (an indicator of mitochondrial mass). These novel findings suggest that reducing muscle hydrogen ion accumulation during running training is associated with greater improvements in both mitochondrial mass and mitochondrial respiration in the soleus.

  • 38.
    Björkman, Frida
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Bohman, Tony
    Ekblom-Bak, Elin
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    The ability of a submaximal cycle ergometer test to detect changes in VO2maxManuscript (preprint) (Other academic)
  • 39.
    Björkman, Frida
    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.
    Edin, Fredrik
    University of Gothenburg.
    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.
    Larsen, Filip
    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.
    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.
    Regular moist snuff dipping does not affect endurance exercise performance.2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 7, article id e0181228Article in journal (Refereed)
    Abstract [en]

    Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users. The effects of snuff cessation after several years of daily use are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks snuff cessation (SCG). A control group (CO) of 11 snuff users kept their normal habits. Resting heart rate (HR) and blood pressure (BP) were significantly lower in SCG after snuff cessation, and body mass was increased by 1.4 ± 1.7 kg. Total cholesterol increased from 4.12 ± 0.54 (95% CI 3.89-4.35) to 4.46 ± 0.70 (95% CI 4.16-4.75) mM L-1 in SCG, due to increased LDL, and this change was significantly different from CO. Resting values of HDL, C-reactive protein, and free fatty acids (FFA) remained unchanged in both groups. In SCG group, both HR and BP were reduced during a four-stage incremental cycling test (from 50 to 80% of VO2max) and a prolonged cycling test (60 min at 50% of VO2max). Oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion (RPE) were unchanged. In CO group, all measurements were unchanged. During the prolonged cycling test, FFA was reduced, but with no significant difference between groups. During the maximal treadmill running test peak values of VO2, pulmonary ventilation (VE), time to exhaustion and bLa were unchanged in both groups. In conclusion, endurance exercise performance (VO2max and maximal endurance time) does not seem to be affected by prolonged snuff use, while effects on cardiovascular risk factors are contradictory. HR and BP during rest and submaximal exercise are reduced after cessation of regular use of snuff. Evidently, the long-time adrenergic stress on circulation is reversible.

  • 40.
    Björkman, Frida
    et al.
    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.
    Edin, Fredrik
    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.
    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.
    Larsen, Filip
    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.
    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.
    Regular oral moist snuff dipping does not impair physical performanceArticle in journal (Refereed)
  • 41.
    Björkman, Frida
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Eggers, Andrea
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Stenman, Adam
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Bohman, Tony
    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.
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Sex and maturity status affected the validity of a submaximal cycle test in adolescents.2018In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 107, no 1, p. 126-133Article in journal (Refereed)
    Abstract [en]

    AIM: This study assessed the validity and reliability of the Ekblom-Bak (EB) submaximal cycle test in adolescents and identified any sex- or maturity-related factors for prediction errors.

    METHODS: We recruited 50 healthy subjects through a public announcement in Stockholm, Sweden, in 2016. The 27 boys and 23 girls were aged 10-15 years and in Tanner stages I-IV. They performed an EB test and incremental treadmill running test for direct measurement of maximal oxygen uptake (VO2 max).

    RESULTS: The estimation error of VO2 max was 0.09 L/min. The correlation (r) was 0.86, and the standard error of the estimate (SEE) was 0.29 L/min. The largest overestimation was seen in prepubertal boys (0.49 L/min). The best precision of the EB test was achieved when boys in Tanner stages I and II were re-calculated using the prediction equation developed for adult women. This yielded a mean difference of -0.05 L/min, r = 0.92 and SEE 0.23 L/min, in the entire sample. The prediction error was lowered in boys, but not girls, with increasing pubertal maturity.

    CONCLUSION: The EB test was reasonably valid in adolescents, seemed to be related to sex and maturity status, and our findings support its use.

    The full text will be freely available from 2018-10-05 12:00
  • 42.
    Björkman, Frida
    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.
    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.
    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.
    Validity of the revised Ekblom Bak cycle ergometer test in adults.2016In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 116, no 9, p. 1627-1638Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To further develop the Ekblom Bak-test prediction equation for estimation of VO2max from submaximal cycle ergometry.

    METHODS: The model group (117 men and 100 women, aged 48.3 ± 15.7 and 46.1 ± 16.8 years, VO2max 46.6 ± 11.1 and 40.4 ± 9.6 mL kg(-1) min(-1), respectively) and the cross-validation group (60 men and 55 women, aged 40.6 ± 17.1 and 41.6 ± 16.7 years, VO2max 49.0 ± 12.1 and 43.2 ± 8.9 mL min(-1) kg(-1), respectively) performed 4 min of cycling on a standard work rate (30 W) directly followed by 4 min on a higher work rate. Heart rate (HR) at each work rate was recorded. Thereafter, participants completed a graded maximal treadmill test for direct measurement of oxygen uptake. The new prediction equation was cross-validated and accuracy compared with the original Ekblom Bak equation as well as by the Åstrand test method.

    RESULTS: The final sex-specific regression models included age, change in HR per-unit change in power (ΔHR/ΔPO), the difference in work rates (ΔPO), and HR at standard work rate as independent variables. The adjusted R (2) for the final models were 0.86 in men and 0.83 in women. The coefficient of variation (CV) was 8.7 % and SEE 0.28 L min(-1). The corresponding CV and SEE values for the EB-test2012 and the Åstrand tests were 10.9 and 18.1 % and 0.35 and 0.48 L min(-1), respectively.

    CONCLUSION: The new EB-test prediction equation provides an easy administered and valid estimation of VO2max for a wide variety of ages (20-86 years) and fitness levels (19-76 mL kg(-1) min(-1)).

  • 43.
    Björkman, Frida Maria Eleonora
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Validity and reliability of a submaximal cycle ergometer test for estimation of maximal oxygen uptake2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Maximal oxygen uptake (VO2max) is the highest obtained rate of oxygen consumption during a physically intense dynamic whole-body activity. VO2max is an important factor for many types of physical performance, as well as a strong independent predictor of health and longevity. Thus, it is important to have accurate and precise methods for assessment of VO2max.

    A direct measurement of VO2max is often conducted via indirect calorimetry during maximal exercise. The demand for maximal effort from an individual, along with the need for laboratory equipment, makes direct measurements unsuitable in the general, non-athlete population. There are also a number of contraindications that limit the possibility to conduct direct measurements of VO2max in many settings. Instead, several other exercise tests have been developed in order to facilitate the procedure of determination and evaluation of cardiorespiratory fitness in different populations. These tests can be either of submaximal or maximal character. Commonly used work modes are stepping, walking, and cycling. The overall aim of this thesis was to describe the background to, and the development of, submaximal cycle ergometer tests for estimation of VO2max.

    The present thesis focuses on the validity and reliability of a new submaximal cycle ergometer test – the Ekblom-Bak test (EB test). The first study described the test procedure for the new cycle ergometer test and the creation of an accompanying mathematical model (prediction equation) for estimation of VO2max. The development of the test and its associated prediction equation was continued in study II, while it was further validated in adults and adolescents in study II and IV. Study III examined the ability to use a submaximal cycle ergometer test in order to detect changes in VO2max over time.

    The EB test comprises of 8 minutes of continuous cycling – 4 minutes at 0.5 kp, followed by 4 minutes at a higher, individually chosen work rate – with a pedalling rate of 60 revolutions per minute. The test measures the change in HR (ΔHR) between the two different work rates (ΔPO), and the variable ΔHR/ΔPO was obtained and linked to measured VO2max. In study I, the validity and reliability of the EB test and the associated prediction equation was tested in a mixed population with regard to sex, age, and physical activity status. The subjects performed repeated submaximal cycle ergometer tests and maximal running tests for direct determination of VO2max (reference value). There was a strong correlation between estimated and measured VO2max, with an adjusted R2 of 0.82 and a corresponding coefficient of variation (CV) of 9.3%. Although there was a relatively high precision in the estimation of VO2max by the prediction equation, it was evident that individuals with high VO2max were underestimated and individuals with low VO2max were overestimated. This issue was further addressed in study II.

    In study II, the size of the study population was increased, in order to broaden the valid range and evaluate the use of sex-specific prediction equations. The estimation error was slightly decreased, and the sex-specific prediction equations resulted in an adjusted R2 of 0.91 and a CV of 8.7% in the whole group. The new models were also evaluated in a cross-validation group, where the adjusted R2 was 0.90 and CV 9.4%.

    The relation between the estimation error and changes in VO2max over time was investigated in study III. Follow-up tests were conducted in 35 subjects, in order to examine the conformity between changes in measured and estimated VO2max over a timespan of 5 to 8 years. Results showed a moderate correlation between change in measured VO2max and change in estimated VO2max (r = 0.75). Changes in body mass or changes in work efficiency did not relate to the change in assessment error. 

    In study IV, the aim was to determine the applicability and validity of the EB test in pre-pubertal and pubertal adolescents. Medical examinations and assessment of sexual maturity (according to the stages of Tanner) were performed in addition to the physical tests. The included subjects (n = 50) were 10 to 15 years old and in Tanner stages I–IV. The measurement error (the difference between measured and estimated VO2max) was related to maturity in boys, but not in girls. The measurement error decreased for the whole group when the equation developed for women was used for the boys in Tanner I and II. This modification in the calculations of VO2max resulted in an adjusted R2 of 0.83 and SEE 0.23 L/min. Hence, the most accurate prediction of VO2max from the EB test is generated if the test result is accompanied by ratings of sexual maturity in adolescents. Analysis of the test-retest values showed no significant change in estimated VO2max from repeated tests within two weeks of each other. 

    In summary, the EB test proved to be a reliable and valid test throughout a wide range of ages (20 to 85 years) and fitness levels (1.33 to 3.94 L/min in women, and 1.67 to 5.97 L/min in men). The test was also found to be useful and reasonably valid for determination of VO2max in pre-pubertal and pubertal adolescents, preferably after adjustment for sexual maturity status in boys. Furthermore, it was shown that the EB test captured fairly well an actual change in VO2max during a period of 5 to 8 years. However, it is still unknown whether the test has an acceptable sensitivity for detection of a training-induced increase in VO2max. Further studies are needed to evaluate if the test can be used in diseased individuals with or without different medications. The EB test can be used in health-related clinical settings, sports and fitness clubs.

  • 44.
    Björkman, Frida
    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.
    Hur farlig är multisport?2011In: Svensk IdrottsMedicin, ISSN 1103-7652, Vol. 30, no 4, p. 8-11Article in journal (Other academic)
    Abstract [sv]

    Den övervägande delen av deltagarna i större multisporttävlingar drabbas av någon typ av skada som i de flesta fall är lindrig. Men det är ändå ingen tvekan om att multisport kan vara farligt. Det ställs höga krav på medicinsk personal att kunna hantera en mångfald av skador och sjukdomar.

  • 45.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    A role for branched-chain amino acids in reducing central fatigue.2006In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 136, no 2, p. 544S-547SArticle in journal (Refereed)
    Abstract [en]

    Several factors have been identified to cause peripheral fatigue during exercise, whereas the mechanisms behind central fatigue are less well known. Changes in the brain 5-hydroxytryptamine (5-HT) level is one factor that has been suggested to cause fatigue. The rate-limiting step in the synthesis of 5-HT is the transport of tryptophan across the blood-brain barrier. This transport is influenced by the fraction of tryptophan available for transport into the brain and the concentration of the other large neutral amino acids, including the BCAAs (leucine, isoleucine, and valine), which are transported via the same carrier system. Studies in human subjects have shown that the plasma ratio of free tryptophan (unbound to albumin)/BCAAs increases and that tryptophan is taken up by the brain during endurance exercise, suggesting that this may increase the synthesis of 5-HT in the brain. Ingestion of BCAAs increases their concentration in plasma. This may reduce the uptake of tryptophan by the brain and also 5-HT synthesis and thereby delay fatigue. Accordingly, when BCAAs were supplied to human subjects during a standardized cycle ergometer exercise their ratings of perceived exertion and mental fatigue were reduced, and, during a competitive 30-km cross-country race, their performance on different cognitive tests was improved after the race. In some situations the intake of BCAAs also improves physical performance. The results also suggest that ingestion of carbohydrates during exercise delays a possible effect of BCAAs on fatigue since the brain's uptake of tryptophan is reduced.

  • 46.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Amino acids and central fatigue.2001In: Amino Acids, ISSN 0939-4451, E-ISSN 1438-2199, Vol. 20, no 1, p. 25-34Article in journal (Refereed)
    Abstract [en]

    There is an increasing interest in the mechanisms behind central fatigue, particularly in relation to changes in brain monoamine metabolism and the influence of specific amino acids on fatigue. Several studies in experimental animals have shown that physical exercise increases the synthesis and metabolism of brain 5-hydroxytryptamine (5-HT). Support for the involvement of 5-HT in fatigue can be found in studies where the brain concentration of 5-HT has been altered by means of pharmacological agents. When the 5-HT level was elevated in this way the performance was impaired in both rats and human subjects, and in accordance with this a decrease in the 5-HT level caused an improvement in running performance in rats. The precursor of 5-HT is the amino acid tryptophan and the synthesis of 5-HT in the brain is thought to be regulated by the blood supply of free tryptophan in relation to other large neutral amino acids (including the branched-chain amino acids, BCAA) since these compete with tryptophan for transport into the brain. Studies in human subjects have shown that the plasma ratio of free tryptophan/BCAA increases during and, particularly, after sustained exercise. This would favour the transport of tryptophan into the brain and also the synthesis and release of 5-HT which may lead to central fatigue. Attempts have been made to influence the 5-HT level by giving BCAA to human subjects during different types of sustained heavy exercise. The results indicate that ingestion of BCAA reduces the perceived exertion and mental fatigue during exercise and improves cognitive performance after the exercise. In addition, in some situations ingestion of BCAA might also improve physical performance; during exercise in the heat or in a competitive race when the central component of fatigue is assumed to be more pronounced than in a laboratory experiment. However, more experiments are needed to further clarify the effect of BCAA and also of tryptophan ingestion on physical performance and mental fatigue.

  • 47.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Branched-chain Amino Acids and Central Fatigue: Implications for Diet and Behavior2011In: Handbook of Behavior, Food and Nutrition / [ed] V.R. Preedy et al., Springer Science + Business Media , 2011, p. 865-877Chapter in book (Other academic)
  • 48.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Fysiologisk forskning åren 1997-20132014In: Från Kungl. Gymnastiska Centralinstitutet till Gymnastik- och idrottshögskolan: en betraktelse av de senaste 25 åren som del av en 200-årig historia / [ed] Suzanne Lundvall, Stockholm: Gymnastik- och idrottshögskolan, GIH , 2014, p. 200-206Chapter in book (Other (popular science, discussion, etc.))
  • 49.
    Blomstrand, Eva
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology, Eva Blomstrand's research group.
    Utilisation of different energy sources during exercise and nutritional strategies for effective recovery2014In: Women and sport, Stockholm: SISU idrottsböcker , 2014Chapter in book (Other academic)
    Abstract [en]

    In this text, we will examine how the body uses the nutrients in food to produce energy during exercise, and whether these processes differ between the sexes. If they do, does this mean that the nutritional requirements should be different for men and women? We will also present current knowledge on the effects of nutrition on recovery after physical activity, a topic that has attracted much interest in the sports world. finally, we will briefl y discuss the nutritional requirements of physically active women and the common nutritional problems they encounter.

  • 50.
    Blomstrand, Eva
    et al.
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Eva Blomstrand's research group.
    Celsing, F
    Newsholme, E A
    Changes in plasma concentrations of aromatic and branched-chain amino acids during sustained exercise in man and their possible role in fatigue.1988In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 133, no 1, p. 115-21Article in journal (Refereed)
    Abstract [en]

    The plasma concentrations of branched-chain and aromatic amino acids have been measured in two different types of sustained dynamic exercise. Twenty-two subjects participated in the 1986 Stockholm Marathon and eight subjects took part in an army training programme of approximately 1.5-h duration. Both types of exercise caused a significant decrease in the plasma concentration of branched-chain amino acids, while there was no change in the concentration of total (free plus bound to albumin) tryptophan. The plasma concentration of free tryptophan, which was measured in the marathon runners, was found to increase 2.4-fold during the race. This increase is probably caused by a pronounced elevation in the concentration of plasma free fatty acids during exercise, since these are known to displace tryptophan from albumin. The observed increase in plasma free tryptophan concentration, together with the decrease in plasma concentration of branched-chain amino acids, gives rise to a marked increase in the plasma concentration ratio of free tryptophan/branched-chain amino acids. This should lead to an increase in the rate of transport of tryptophan across the blood-brain barrier and hence to an increase in the rate of synthesis of 5-hydroxytryptamine (5-HT) in the brain. An elevated concentration of 5-HT in specific areas of the brain may be responsible, at least in part, for the development of physical, and/or mental fatigue during prolonged exercise.

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