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  • 301.
    Kallings, Lena
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Hur ska vi fråga om fysisk aktivitet?2016Ingår i: Idrottsmedicin, ISSN 2001-3302, Vol. 35, nr 3, s. 20-23Artikel i tidskrift (Övrigt vetenskapligt)
  • 302.
    Kallings, Lena
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Olsson, Sven Johan Gustav
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Börjesson, Mats
    Göteborg Universitet.
    The SED-GIH: A Single-Item Question for Assessment of Stationary Behavior-A Study of Concurrent and Convergent Validity.2019Ingår i: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, nr 23, artikel-id E4766Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The unfavorable health consequences of prolonged time spent sedentary (stationary) make accurate assessment in the general population important. However, for many existing questionnaires, validity for identifying stationary time has not been shown or has shown low validity. This study aimed to assess the concurrent and convergent validity of the GIH stationary single-item question (SED-GIH). Data were obtained in 2013 and 2014 from two Swedish cohorts. A total of 711 men and women provided valid accelerometer data (Actigraph GT3X+) and were included for concurrent validity analyses. A total of 560 individuals answered three additional commonly used sedentary questions, and were included for convergent validity analysis. The SED-GIH displayed a significant correlation with total stationary time (rs = 0.48) and time in prolonged stationary time (rs = 0.44). The ROC analysis showed an AUC of 0.72 for identifying individuals with stationary time over 600 min/day. The SED-GIH correlated significantly with other previously used questions (r = 0.72-0.89). The SED-GIH single-item question showed a relatively high agreement with device-assessed stationary behavior and was able to identify individuals with high levels of stationary time. Thus, the SED-GIH may be used to assess total and prolonged stationary time. This has important implications, as simple assessment tools of this behavior are needed in public health practice and research.

  • 303.
    Kallings, Lena V
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    The organisation of promoting physical activity in health care – examples from the Nordic countries.2016Ingår i: Clinical Health Promotion - research and best practice for patients, staff and community., ISSN 2226-5864, Vol. 6, nr Suppl 2, s. 27-30Artikel i tidskrift (Övrigt vetenskapligt)
  • 304.
    Kallings, Lena V
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    The Swedish approach on physical activity on prescription2016Ingår i: Clinical Health Promotion - research and best practice for patients, staff and community, ISSN 2226-5864, Vol. 6, nr Suppl 2, s. 31-33Artikel i tidskrift (Övrigt vetenskapligt)
  • 305.
    Kallings, Lena V
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Hellénius, M-L
    Karolinska Institutet.
    Physical activity on prescription reduces sedentary behaviour for 6 months, without long term effect2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Objectives

    There is a lack of knowledge regarding methods to reduce sedentary behaviour. The aim of this study was to evaluate the efficacy of physical activity on prescription (PAP) in patients with overweight and abdominal obesity. PAP decrease sitting time at 6-months follow-up in this population, and data is now further analysed to study the longterm effect.

    Methods

    Six month randomised controlled study in 101 women and men (57% female, 67-68 year). All participants received a minimal intervention with brief general information on physical activity and measurement of PAL. The intervention group received in addition an individualized PAP that consisted of a patient centred counselling and a written agreement. Focus of the intervention was to reduce sedentary behaviour as well as to promote an increased PAL. Sedentary behaviour was assessed by questionnaire, the sitting item from IPAQ.

    Results

    Both groups reduced sitting time from baseline to 6-months follow-up, intervention group by 114 min/day and control group by 86 min/day. However, the changes disappeared at the long term follow-ups (Figure). There were no significant differences between the groups at either time point.

    Conclusions

    It is possible to reduce sitting time in overweight individuals. An individualized prescription of physical activity reduces sedentary behaviour for 6 months, but had no long term effects. There was no significant better effect of PAP compared to a minimal intervention. Studies with more subjects and objective methods are needed.

  • 306. Kalsen, Anders
    et al.
    Hostrup, Morten
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Karlsson, Sebastian
    Backer, Vibeke
    Bangsbo, Jens
    Inhaled Beta2-agonist Increases Power Output and Glycolysis during Sprinting in Men.2016Ingår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 48, nr 1, s. 39-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE: The aim of the present study was to investigate the effect of the beta2-agonist terbutaline (TER) on power output and muscle metabolism during maximal sprint cycling.

    METHODS: In a randomized double-blind crossover design, nine moderately trained men (VO2max: 4.6±0.2 L[BULLET OPERATOR]min) conducted a 10-s cycle sprint after inhalation of either 15 mg TER or placebo (PLA). A muscle biopsy was collected before and <10 s after the sprint, and analyzed for metabolites.

    RESULTS: Mean and peak power during the sprint were 8.3±1.1 and 7.8±2.5 % higher (P<0.05) in TER than in PLA, respectively. Moreover, net rate of glycogenolysis (6.5±0.8 vs. 3.1±0.7 mmol glucosyl units kg dw s) and glycolysis (2.4±0.2 vs. 1.6±0.2 mmol glucosyl units kg dw s) were higher (P<0.05) in TER than in PLA. After the sprint, ATP was reduced in PLA (P<0.05), but not in TER. During the sprint, there was no difference in breakdown of phosphocreatine (PCr) between treatments. Estimated anaerobic ATP utilization was 9.2 ±4.0 % higher (P<0.05) in TER than in PLA. After the sprint, ATP was lowered (P <0.05) by 25.7±7.3 % in type II fibers in PLA with no reduction in TER. Before the sprint, PCr was 24.5±7.2 % lower (P <0.05) in type II fibers in TER than in PLA. In PLA, breakdown of PCr was 50.2±24.8 % higher (P <0.05) in type II than in type I fibers with no difference in TER.

    CONCLUSION: The present study shows that a terbutaline-induced increase in power output is associated with increased rates of glycogenolysis and glycolysis in skeletal muscles. Furthermore, as terbutaline counteracted a reduction in ATP in type II fibers, terbutaline may postpone fatigue development in these fibers.

  • 307. Karazizi, Christina
    et al.
    Onerup, Aron
    Larsson, Pia
    Karlsson, Lena
    Börjesson, Mats
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Dutta Roy, Smita
    The effect of exercise on angiogenic factors in the healthy mouse heart: a short report2014Ingår i: Experimental and clinical cardiology, ISSN 1205-6626, Vol. 20, nr 1, s. 2332-41Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Exercise increases blood levels of crucial angiogenic factors and endothelial progenitor cells (EPCs). Hypoxia inducible factor-1 (HIF-1a) and vascular endothelial growth factor (VEGF) are also increased in skeletal muscle in response to exercise. In the healthy heart, voluntary exercise is not expected to cause local hypoxia. We studied how voluntary exercise affects cardiac expression of HIF-1a, VEGF and stromal derived factor-1 (SDF-1), as well as EPC levels in heart and skeletal muscle.

    Method: Thirty-two NMRI mice were randomized to exercise in running wheels (EX) or regular activity (SED). HIF-1a, VEGF and SDF-1 mRNA levels were analyzed by reverse transcription polymerase chain reaction (RTPCR) and EPC levels in heart and hind limb were quantified by FACS after 7 and 14 days.

    Results: There was no significant difference in cardiac expression of HIF-1a, VEGF or SDF-1 between EX and SED. Cardiac EPC levels were not affected by exercise, while skeletal EPC level was more than doubled.

    Conclusion: Voluntary exercise does not seem to induce cardiac hypoxia or stimulate the angiogenic system. In the healthy normoxic heart, there is a limited need of supporting blood supply, which might explain these findings.

  • 308. Karlsson, Håkan K R
    et al.
    Nilsson, Per-Anders
    Nilsson, Johnny
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Chibalin, Alexander V
    Zierath, Juleen R
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Eva Blomstrands forskningsgrupp.
    Branched-chain amino acids increase p70S6k phosphorylation in human skeletal muscle after resistance exercise.2004Ingår i: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 287, nr 1, s. E1-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of the study was to investigate the effect of resistance exercise alone or in combination with oral intake of branched-chain amino acids (BCAA) on phosphorylation of the 70-kDa S6 protein kinase (p70(S6k)) and mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK1/2), and p38 MAPK in skeletal muscle. Seven male subjects performed one session of quadriceps muscle resistance training (4 x 10 repetitions at 80% of one repetition maximum) on two occasions. In a randomized order, double-blind, crossover test, subjects ingested a solution of BCAA or placebo during and after exercise. Ingestion of BCAA increased plasma concentrations of isoleucine, leucine, and valine during exercise and throughout recovery after exercise (2 h postexercise), whereas no change was noted after the placebo trial. Resistance exercise led to a robust increase in p70(S6k) phosphorylation at Ser(424) and/or Thr(421), which persisted 1 and 2 h after exercise. BCAA ingestion further enhanced p70(S6k) phosphorylation 3.5-fold during recovery. p70(S6k) phosphorylation at Thr(389) was unaltered directly after resistance exercise. However, during recovery, Thr(389) phosphorylation was profoundly increased, but only during the BCAA trial. Furthermore, phosphorylation of the ribosomal protein S6 was also increased in the recovery period only during the BCAA trial. Exercise led to a marked increase in ERK1/2 and p38 MAPK phosphorylation, which was completely suppressed upon recovery and unaltered by BCAA. In conclusion, BCAA, ingested during and after resistance exercise, mediate signal transduction through p70(S6k) in skeletal muscle.

  • 309. Kazior, Zuzanna
    et al.
    Willis, Sarah J
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Calbet, José A L
    Holmberg, Hans-Christer
    Blomstrand, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Eva Blomstrands forskningsgrupp.
    Endurance Exercise Enhances the Effect of Strength Training on Muscle Fiber Size and Protein Expression of Akt and mTOR.2016Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 2, artikel-id e0149082Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reports concerning the effect of endurance exercise on the anabolic response to strength training have been contradictory. This study re-investigated this issue, focusing on training effects on indicators of protein synthesis and degradation. Two groups of male subjects performed 7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding endurance exercise, including both continuous and interval cycling (ER; n = 9). Muscle biopsies were taken before and after the training period. Similar increases in leg-press 1 repetition maximum (30%; P<0.05) were observed in both groups, whereas maximal oxygen uptake was elevated (8%; P<0.05) only in the ER group. The ER training enlarged the areas of both type I and type II fibers, whereas the R protocol increased only the type II fibers. The mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant increase was observed in the R group. Moreover, expression of Akt and mTOR protein was enhanced in the ER group, whereas only the level of mTOR was elevated following R training. Training-induced alterations in the levels of both Akt and mTOR protein were correlated to changes in type I fiber area (r = 0.55-0.61, P<0.05), as well as mean fiber area (r = 0.55-0.61, P<0.05), reflecting the important role played by these proteins in connection with muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05) and tended to elevate that of MuRF-1. The present findings indicate that the larger hypertrophy observed in the ER group is due more to pronounced stimulation of anabolic rather than inhibition of catabolic processes.

  • 310.
    Khalaf, Atika
    et al.
    Högskolan i Kristianstad.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Kowalski, Jan
    Berggren, Vanja
    Karolinska Institutet.
    Westergren, Albert
    Högskolan i Kristianstad.
    al-Hazzaa, Hazzaa
    College of Education and Obesity Research Chair, King Saud University, Saudi Arabia.
    Female University Students’ Physical Activity Levels and Associated Factors — A Cross-Sectional Study in Southwestern Saudi Arabia2013Ingår i: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 10, nr 8, s. 3502-3517Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The high prevalence of physical inactivity in Saudi Arabia is a growing challenge to public health. This study aimed to examine the prevalence of physical activity (PA) and associated factors among female university students. Methods: This cross-sectional study involved 663 randomly selected female university students who completed the Arab Teens Life Style questionnaire. Data included measurements of anthropometric, socioeconomic and environmental factors, as well as self-reported PA. Ordinal regression was used to identify associated factors with low, moderate and high PA levels.Results: The mean age of participants was 20.4 years (SD 1.5). Mean BMI of the students in relation to PA were 23.0, 22.9, 22.1 for high, moderate and low levels of activity, respectively. The analysis revealed significantly higher PA levels among married students, those with high educated mothers, and those who lived far from parks, and lower activity levels among underweight students. Conclusions: This study raises four important determinants for female university students’ PA levels. These factors could be of great importance in the endeavor to prevent the health-threatening increase in physical inactivity patterns and thus non-communicable diseases and obesity where the focus should be on the specific situation and needs of women in Saudi Arabia.

  • 311. Khalaf, Atika
    et al.
    Westergren, Albert
    Berggren, Vanja
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Al-Hazzaa, Hazzaa M.
    Perceived and Ideal Body Image in Young Women in South Western Saudi Arabia.2015Ingår i: Journal of Obesity, ISSN 2090-0708, E-ISSN 2090-0716, artikel-id 697163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objectives. The aim of this study was to investigate perceived and ideal body image (BI) and associated factors among female university students in Saudi Arabia. Methods. This cross-sectional study included 663 university female students. Anthropometric measurements including weight, height, BMI, and BI perception (the 9-figure silhouette) were obtained. Descriptive and logistic regression analysis were conducted. Results. An agreement between actual, perceived, and ideal BI was found in 23% of the participants. Behavioral (activity levels), social (presence of obese parents and fathers’ level of education), and economic factors (households’ monthly income, number of cars in the household, and kind of residence) were positively and significantly associated with the desire to be thinner. Similarly, socioeconomic associations (number of sisters and number of cars in the household) correlated positively and significantly with the desire to be heavier. Conclusions. The whole family should rather be considered in interventions related to appearance concerns and BI discrepancies. Furthermore, campaigns targeting improvement of adolescents’ physical self-image should be a major priority of the public health sector. [ABSTRACT FROM AUTHOR]

  • 312. Khalaf, Atika
    et al.
    Westergren, Albert
    Berggren, Vanja
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Al-Hazzaa, Hazzaa M
    Prevalence and association of female weight status and dietary habits with sociodemographic factors: a cross-sectional study in Saudi Arabia.2015Ingår i: Public Health Nutrition, ISSN 1368-9800, E-ISSN 1475-2727, Vol. 18, nr 5, s. 784-796Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: Research about the prevalence of underweight and overweight/obesity in the Saudi Arabian female population is limited. The aim of the present study was to examine the dietary habits and the prevalence of underweight and overweight/obesity and associated factors among female university students.

    DESIGN: A cross-sectional study.

    SETTING: A university centre for female students in south-western Saudi Arabia.

    SUBJECTS: The study involved 663 randomly selected female university students who self-reported their physical activities, nutritional habits and socio-economic factors. Multiple linear and logistic regression analyses were used to identify factors associated with the students' BMI, dietary variables, underweight and overweight/obesity.

    RESULTS: The majority of the university females were normal weight (56·9 %), but a high prevalence of underweight (19·2 %) and overweight/obesity (23·8 %) occurred. Social factors significantly associated with BMI were the presence of obese parents and siblings as well as physical activity levels, marital status, number of sisters, father's level of education and more frequent intake of French fries/potato chips (>3 times/week). Several variables were found to correlate with dietary habits, underweight and overweight/obesity. Of special interest is the association between the number of siblings and the participants' BMI and dietary intake in both negative and positive ways.

    CONCLUSIONS: The findings of this research have implications for health promotion and prevention of malnutrition among college-aged females. Health-care providers and policy makers need to involve the whole family when promoting females' physical activity. The study serves as an evidence-based background for planning and implementation of interventions targeting improvement of highly educated populations' nutritional habits.

  • 313. Khalaf, Atika
    et al.
    Westergren, Albert
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Al-Hazzaa, Hazzaa M
    Berggren, Vanja
    Nurses' views and experiences of caring for malnourished patients in surgical settings in Saudi Arabia - a qualitative study.2014Ingår i: BMC Nursing, ISSN 1472-6955, E-ISSN 1472-6955, Vol. 13, s. 29-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Although the occurrence of malnutrition in hospitals is a growing concern, little is known about how hospital staff understand the care that nurses provide to patients with malnutrition. The purpose of this study was to explore nurses' views and experiences of caring for malnourished patients in Saudi Arabia (KSA).

    METHODS: Using a qualitative explorative design, fifteen nurses were interviewed as part of a purposive sample hospital staff. The transcripts were analyzed using latent content analysis.

    RESULTS: The nurses spontaneously and consistently linked malnutrition with physical inactivity. The two main categories, which emerged, were: 'Potentials for nurses to provide good nutrition and physical activity', and 'Having the ability but not the power to promote proper nutrition and physical activity'. These arose from the subcategories: Good nursing implies providing appropriate health education; Acknowledging the Mourafiq (sitter) as a potential resource for the nursing, but also as a burden; Inadequate control and lack of influence; Cultural diversity and lack of dialog; and Views of women's weight gain in KSA society.

    CONCLUSIONS: The nurses felt they have the capacity and passion to further improve the nutrition and activity of their patients, but obstacles in the health care system are impeding these ambitions. The implications for nursing practice could be acknowledgement of the nurses' views in the clinical practice; culturally adjusted care, improved communication and enhanced language skills.

  • 314.
    Krustrup, Peter
    et al.
    Inst of exercise and sport sciences dept of human physiology, August Krogh inst, University of Copenhagen .
    Secher, Niels H
    Relu, Mihai U
    Hellsten, Ylva
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Bangsbo, Jens
    Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans.2008Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 586, nr Pt 24, s. 6037-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 315. Krustrup, Peter
    et al.
    Söderlund, Karin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Mohr, Magni
    Bangsbo, Jens
    Slow-twitch fiber glycogen depletion elevates moderate-exercise fast-twitch fiber activity and O2 uptake.2004Ingår i: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 36, nr 6, s. 973-82Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 316.
    Kuster, Roman P
    et al.
    Karolinska Institutet, Stockholm, Sweden.
    Grooten, Wilhelmus J A
    Karolinska Institutet, Stockholm, Sweden.
    Baumgartner, Daniel
    ZHAW Zurich University of Applied Sciences, Winterthur, Switzerland..
    Blom, Victoria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet. Karolinska Institutet, Stockholm, Sweden.
    Hagströmer, Maria
    Karolinska Institutet, Stockholm, Sweden.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Detecting Prolonged Sitting Bouts with the ActiGraph GT3X.2019Ingår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The ActiGraph has a high ability to measure physical activity, however, it lacks an accurate posture classification to measure sedentary behaviour. The aim of the present study was to develop an ActiGraph (waist-worn, 30Hz) posture classification to detect prolonged sitting bouts, and to compare the classification to proprietary ActiGraph data. The activPAL, a highly valid posture classification device, served as reference criterion.1 Both sensors were worn by 38 office workers over a median duration of 9 days. An automated feature selection extracted the relevant signal information for a minute based posture classification. The machine-learning algorithm with optimal feature number to predict the time in prolonged sitting bouts (≥5 and ≥10 minutes) was searched and compared to the activPAL using Bland-Altman statistics. The comparison included optimised and frequently used cut-points (100 and 150 counts-per-minute (cpm), with and without low-frequency-extension (LFE) filtering). The new algorithm predicted the time in prolonged sitting bouts most accurate (bias ≤7 minutes/day). Of all proprietary ActiGraph methods, only 150 cpm without LFE predicted the time in prolonged sitting bouts non-significantly different from the activPAL (bias ≤18 minutes/day). However, the frequently used 100 cpm with LFE accurately predicted total sitting time (bias ≤7 minutes/day). To study the health effects of ActiGraph measured prolonged sitting, we recommend using the new algorithm. In case a cut-point is used, we recommend 150 cpm without LFE to measure prolonged sitting, and 100 cpm with LFE to measure total sitting time. However, both cpm cut-points are not recommended for a detailed bout analysis.

  • 317.
    Larsen, Filip
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Effects of dietary nitrate on oxygen cost during exercise2007Ingår i: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 191, nr 1, s. 59-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 318.
    Larsen, Filip
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    The low intracellular oxygen tension during exercise is a function of limited oxygen supply and high mitochondrial oxygen affinity: A letter to the editor2012Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, nr 11, s. 3935-3936Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    A letter to the editor is presented in response to an article on muscle intracellular oxygenation during exercise published in a previous issue of the journal.

  • 319.
    Larsen, Filip
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Sahlin, Kent
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Mitochondrial oxygen affinity predicts basal metabolic rate in humans2011Ingår i: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 25, nr 8, s. 2843-52Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The basal metabolic rate (BMR) is referred to as the minimal rate of metabolism required to support basic body functions. It is well known that individual BMR varies greatly, even when correcting for body weight, fat content, and thyroid hormone levels, but the mechanistic determinants of this phenomenon remain unknown. Here, we show in humans that mass-related BMR correlates strongly to the mitochondrial oxygen affinity (p50(mito); R(2)=0.66, P=0.0004) measured in isolated skeletal muscle mitochondria. A similar relationship was found for oxygen affinity and efficiency during constant-load submaximal exercise (R(2)=0.46, P=0.007). In contrast, BMR did not correlate to overall mitochondrial density or to proton leak. Mechanistically, part of the p50(mito) seems to be controlled by the excess of cytochrome c oxidase (COX) protein and activity relative to other mitochondrial proteins. This is illustrated by the 5-fold increase in p50(mito) after partial cyanide inhibition of COX at doses that do not affect maximal mitochondrial electron flux through the ETS. These data suggest that the interindividual variation in BMR in humans is primarily explained by differences in mitochondrial oxygen affinity. The implications of these findings are discussed in terms of a trade-off between aerobic efficiency and power.

  • 320.
    Larsen, Filip
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Sahlin, Kent
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Weitzberg, Eddie
    Lundberg, Jon
    Effects of dietary nitrate on blood pressure in healthy volunteers2006Ingår i: New England Journal of Medicine, ISSN 0028-4793, E-ISSN 1533-4406, Vol. 28, nr 355(26), s. 2792-3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To the Editor:

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

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

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

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

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

  • 321.
    Larsen, Filip J
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Anderson, Martin
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Nyström, Thomas
    Cardiorespiratory fitness predicts insulin action and secretion in healthy individuals.2012Ingår i: Metabolism: Clinical and Experimental, ISSN 0026-0495, E-ISSN 1532-8600, Vol. 61, nr 1, s. 12-6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Long-term cardiorespiratory fitness (CRF) and the development of type 2 diabetes mellitus are inversely correlated. Here, we examined the relationships between peak oxygen uptake (VO(2)peak), on the one hand, and glucose infusion rate at rest (GIR(rest)) and during exercise (GIR(exercise)), as well as insulin secretion (both the early and late phases of response [area under the curve {AUC}(insulin)]), on the other. Eight male and 4 female healthy, lean, nonsmoking volunteers were recruited. The VO(2)peak was measured during graded exercise on a cycle ergometer until exhaustion was reached. The GIR(rest) and GIR(exercise) were determined using a euglycemic-hyperinsulinemic clamp, and insulin secretion at rest was evaluated with an intravenous glucose tolerance test. The VO(2)peak correlated positively to GIR(rest) (r = 0.81, P = .001) and GIR(exercise) (r = 0.87, P < .001) and negatively to AUC(insulin) (r = -0.64, P = .03). The respiratory exchange ratio (RER) during insulin infusion was positively correlated to GIR(rest) (r = 0.83, P < .001) and GIR(exercise) (r = 0.86, P < .01) and negatively correlated to both the early insulin response (r = -0.86, P < .0001) and AUC(insulin) (r = -0.87, P = .001). The VO(2)peak accounted for 45% of the variability in RER (R(2) = 0.45, P = .035). In this healthy population, CRF and RER were highly correlated to insulin sensitivity and secretion, as well as to the ability to alter the substrate being oxidized during exercise. These findings highlight the importance of good CRF to maintaining normal insulin action.

  • 322.
    Larsen, Filip J
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Schiffer, Tomas A
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Mattsson, Mathias P
    Checa, Antonio
    Wheelock, Craig E
    Nyström, Thomas
    Lundberg, Jon O
    Weitzberg, Eddie
    Dietary nitrate reduces resting metabolic rate: a randomized, crossover study in humans.2014Ingår i: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, Vol. 99, nr 4, s. 843-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Nitrate, which is an inorganic anion abundant in vegetables, increases the efficiency of isolated human mitochondria. Such an effect might be reflected in changes in the resting metabolic rate (RMR) and formation of reactive oxygen species. The bioactivation of nitrate involves its active accumulation in saliva followed by a sequential reduction to nitrite, nitric oxide, and other reactive nitrogen species.

    OBJECTIVE: We studied effects of inorganic nitrate, in amounts that represented a diet rich in vegetables, on the RMR in healthy volunteers.

    DESIGN: In a randomized, double-blind, crossover study, we measured the RMR by using indirect calorimetry in 13 healthy volunteers after a 3-d dietary intervention with sodium nitrate (NaNO3) or a placebo (NaCl). The nitrate dose (0.1 mmol · kg(-1) · d(-1)) corresponded to the amount in 200-300 g spinach, beetroot, lettuce, or other vegetable that was rich in nitrate. Effects of direct nitrite exposure on cell respiration were studied in cultured human primary myotubes.

    RESULTS: The RMR was 4.2% lower after nitrate compared with placebo administration, and the change correlated strongly to the degree of nitrate accumulation in saliva (r(2) = 0.71). The thyroid hormone status, insulin sensitivity, glucose uptake, plasma concentration of isoprostanes, and total antioxidant capacity were unaffected by nitrate. The administration of nitrite to human primary myotubes acutely inhibited respiration.

    CONCLUSIONS: Dietary inorganic nitrate reduces the RMR. This effect may have implications for the regulation of metabolic function in health and disease.

  • 323.
    Larsen, Filip J
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Schiffer, Tomas A
    Ørtenblad, Niels
    Zinner, Christoph
    Morales-Alamo, David
    Willis, Sarah J
    Calbet, Jose A
    Holmberg, Hans-Christer
    Boushel, Robert
    High-intensity sprint training inhibits mitochondrial respiration through aconitase inactivation.2016Ingår i: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 30, nr 1, s. 417-427Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intense exercise training is a powerful stimulus that activates mitochondrial biogenesis pathways and thus increases mitochondrial density and oxidative capacity. Moderate levels of reactive oxygen species (ROS) during exercise are considered vital in the adaptive response, but high ROS production is a serious threat to cellular homeostasis. Although biochemical markers of the transition from adaptive to maladaptive ROS stress are lacking, it is likely mediated by redox sensitive enzymes involved in oxidative metabolism. One potential enzyme mediating such redox sensitivity is the citric acid cycle enzyme aconitase. In this study, we examined biopsy specimens of vastus lateralis and triceps brachii in healthy volunteers, together with primary human myotubes. An intense exercise regimen inactivated aconitase by 55-72%, resulting in inhibition of mitochondrial respiration by 50-65%. In the vastus, the mitochondrial dysfunction was compensated for by a 15-72% increase in mitochondrial proteins, whereas H2O2 emission was unchanged. In parallel with the inactivation of aconitase, the intermediary metabolite citrate accumulated and played an integral part in cellular protection against oxidative stress. In contrast, the triceps failed to increase mitochondrial density, and citrate did not accumulate. Instead, mitochondrial H2O2 emission was decreased to 40% of the pretraining levels, together with a 6-fold increase in protein abundance of catalase. In this study, a novel mitochondrial stress response was highlighted where accumulation of citrate acted to preserve the redox status of the cell during periods of intense exercise.-Larsen, F. J., Schiffer, T. A., Ørtenblad, N., Zinner, C., Morales-Alamo, D., Willis, S. J., Calbet, J. A., Holmberg, H.-C., Boushel, R. High-intensity sprint training inhibits mitochondrial respiration through aconitase inactivation.

  • 324.
    Larsen, Filip J
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Weitzberg, Eddie
    Lundberg, Jon O
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Dietary nitrate reduces maximal oxygen consumption while maintaining work performance in maximal exercise.2010Ingår i: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 48, nr 2, s. 342-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 325.
    Larsen, Filip
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Schiffer, TA
    Borniquel, S
    Sahlin, Kent
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Lundberg, JO
    Weitzberg, E
    Dietary inorganic nitrate improves mitochondrial efficiency in humans.2011Ingår i: Cell Metabolism, ISSN 1550-4131, Vol. 13, nr 2, s. 149-159Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 326. Larsen, Steen
    et al.
    Scheede-Bergdahl, Celena
    Whitesell, Thomas
    Boushel, Robert
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Bergdahl, Andreas
    Increased intrinsic mitochondrial respiratory capacity in skeletal muscle from rats with streptozotocin-induced hyperglycemia.2015Ingår i: Physiological Reports, E-ISSN 2051-817X, Vol. 3, nr 7, artikel-id e12467Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Type I diabetes mellitus (T1DM) is a chronic disorder, characterized by an almost or complete insulin deficiency. Widespread tissue dysfunction and deleterious diabetes-complications are associated with long-term elevations of blood glucose. The aim of this study was to investigate the effects of type I diabetes, as induced by streptozotocin, on the mitochondria in skeletal muscles that predominantly consist of either slow or fast twitch fibers. Soleus (primarily slow twitch fiber type) and the plantaris muscle (mainly fast twitch fiber type) were removed in order to measure mitochondrial protein expression and integrated mitochondrial respiratory function. Mitochondrial capacity for oxidative phosphorylation (OXPHOS) was found to be higher in the slow (more oxidative) soleus muscle from STZ rats when evaluating lipid and complex I linked OXPHOS capacity, whereas no difference was detected between the groups when evaluating the more physiological complex I and II linked OXPHOS capacity. These findings indicate that chronic hyperglycemia results in an elevated intrinsic mitochondrial respiratory capacity in both soleus and, at varying degree, plantaris muscle, findings that are consistent with human T1DM patients.

  • 327.
    Larsson, Kristina
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap. Sophiahemmet University.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Kallings, Lena
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC). Karolinska institutet.
    Blom, Victoria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen för idrottspsykologi. Karolinska institutet.
    Job Demand-Control-Support Model as Related to Objectively Measured Physical Activity and Sedentary Time in Working Women and Men.2019Ingår i: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, nr 18, artikel-id E3370Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A physically active lifestyle incurs health benefits and physically active individuals show reduced reactivity to psychosocial stressors. However, the findings are inconclusive and are based on self-reported physical activity and sedentary time. The present study aimed at studying the associations between psychological stressors (job demand, control, support, JD-C-S) and objectively measured physical activity (PA) on various intensities from sedentary (SED) to vigorous physical activity. The participants were 314 employees from a cross-sectional study. PA data were collected with the accelerometer ActiGraph GT3X (Pensacola, FL, USA), SED data with the inclinometer activPAL (PAL Technologies Ltd., Glasgow, Scotland, UK), and psychosocial stressors with a web questionnaire. Results showed that vigorous-intensity PA was negatively associated with demand (β -0.15, p < 0.05), even when adjusted for the covariates. SED was negatively associated to support (β -0.13, p < 0.05). Stress significantly moderated relations between support and sedentary time (β -0.12, p < 0.05). Moderate PA (MVPA) was negatively associated with demand, but only when controlling for overtime (β -0.13, p < 0.05). MVPA was also negatively associated with control (β -0.15, p < 0.05) but not when work engagement was included in the model. Being more physically active and spending less time sedentary may help to handle job situations with high demand and low support.

  • 328.
    Larsson, Kristina
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap.
    Kallings, Lena
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Blom, Victoria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen för idrottspsykologi.
    Andersson, Eva
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Ekblom, Maria
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Laboratoriet för biomekanik och motorisk kontroll (BMC).
    Criterion validity and test-retest reliability of SED-GIH, a single item question for assessment of daily sitting time.2019Ingår i: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 19, nr 1, artikel-id 19:17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Sedentary behaviour has been closely linked to metabolic and cardiovascular health and is therefore of importance in disease prevention. A user-friendly tool for assessment of sitting time is thus needed. Previous studies concluded that the present tools used to assess a number of sedentary behaviours are more likely to overestimate sitting than single-item questions which often underestimate sitting time, and that categorical answering options are recommended. In line with this, the single-item question with categorical answering options, SED-GIH, was developed. The aim of this study was to investigate the criterion validity of the SED-GIH question using activPAL3 micro as the criterion measure. The second aim was to evaluate the test-retest reliability of the SED-GIH questionnaire.

    METHOD: In the validity section of this study, 284 middle-aged adults answered a web questionnaire, which included SED-GIH, wore activPAL and filled in a diary log for one week. Spearman's rho assessed the relationship between the SED-GIH answers and the daily average sitting time as monitored by the activPAL (activPAL-SIT), a Weighted Kappa assessed the agreement, ANOVA assessed differences in activPAL-SIT between the SED-GIH answer categories, and a Chi2 compared the proportions of hazardous sitters between the different SED-GIH answer categories. In the reliability section, 95 elderly participants answered the SED-GIH question twice, with a mean interval of 5.2 days. The reliability was assessed with ICC and a weighted Kappa.

    RESULTS: The SED-GIH question correlated moderately with activPAL-SIT (rho = 0.31), with a poor agreement (weighted Kappa 0.12). In total, 40.8% underestimated and 22.2% overestimated their sitting time. The ANOVA showed significant differences in activPAL-SIT between the different SED-GIH answer categories (p < 0.001). The Chi2 showed a significant difference in proportion of individuals sitting more than 10 h per day within each SED-GIH answer category. ICC for the test-retest reliability of SED-GIH was excellent with ICC = 0.86, and the weighted Kappa showed an agreement of 0.77.

    CONCLUSIONS: The unanchored single item SED-GIH question showed excellent reliability but poor validity in the investigated populations. Validity and reliability of SED-GIH is in line with other questionnaires that are commonly used when assessing sitting time.

  • 329. Leijon, M.
    et al.
    Kallings, Lena
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Faskunger, J.
    Lärum, G.
    Börjesson, Mats
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Ståhle, A.
    Thúc đẩy hoạt động thể lực Chương 4. [Promoting physical activity. Chapter 4].2012Ingår i: HOạT ĐộNG THể LựC TRONG PHÒNG VÀ ĐIềU TRị BệNH. [Professional associations for physical activity YFA. Physical Activity in the Prevention and Treatment of Disease (In Vietnamese)]., Nhà xuất bản Y học Hà Nội, năm , 2012, s. 93-114Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 330.
    Lidin, Matthias
    et al.
    Karolinska institutet.
    Ekblom-Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Rydell Karlsson, Monica
    Karolinska institutet.
    Hellénius, Mai-Lis
    Karolinska institutet.
    Long-term effects of a Swedish lifestyle intervention programme on lifestyle habits and quality of life in people with increased cardiovascular risk.2018Ingår i: Scandinavian Journal of Public Health, ISSN 1403-4948, E-ISSN 1651-1905, Vol. 46, nr 6, s. 613-622, artikel-id 1403494817746536Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AIMS: The aim of this study was to evaluate the effects of a structured intervention programme on lifestyle habits and quality of life after six months and one year in participants with increased cardiovascular risk.

    METHODS: Participants aged ≥18 years with increased cardiovascular risk were referred from primary health care and hospitals. The programme was launched at an outpatient clinic in a department of cardiology at a university hospital. It consisted of individual visits to a nurse for a health check-up and lifestyle counselling at baseline, after six months and at one year. In addition, five group sessions - focusing on nicotine, alcohol, physical activity, eating habits, stress, sleep and behavioural change - were offered to the participants and their relatives or friends. Lifestyle habits and quality of life were assessed with questionnaires at baseline, after six months and at one year.

    RESULTS: One hundred participants (64 women, 36 men, age 58±11 years) were included in the programme. Compared with the baseline, significant and favourable changes in reported lifestyle habits were noted. Exercise levels were higher after one year and sedentary time decreased from 7.4 to 6.3 h/day. Dietary habits improved and the number of participants with a high consumption of alcohol decreased. Quality of life improved after one year.

    CONCLUSIONS: Participating in a structured lifestyle programme resulted in improved lifestyle habits and quality of life over one year in people with increased cardiovascular risk. Components such as an inter-professional teamwork, a focus on lifestyle rather than the disease, and combining individual visits and group sessions, might be central to the positive outcome of the programme.

  • 331.
    Lidin, Matthias
    et al.
    Karolinska Institutet.
    Hellénius, Mai-Lis
    Karolinska Institutet.
    Ekblom Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Rydell Karlsson, Monica
    Karolinska Institutet.
    Experiences from individuals with increased cardiovascular risk participating in a one-year lifestyle program.2019Ingår i: European Journal of Cardiovascular Nursing, ISSN 1474-5151, E-ISSN 1873-1953, Vol. 18, nr 7, s. 554-561, artikel-id 1474515119848967Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: The purpose of the current study was to describe the participants' experiences of a structured lifestyle program for persons with high cardiovascular risk.

    METHOD: Sixteen participants with high cardiovascular risk participating in a one-year structured lifestyle intervention program were interviewed regarding their experiences of the program. The interviews were analyzed using content analyses.

    RESULTS: The participants' (mean age 58 ± 9) experiences were categorized into three categories: "How to know," based on the participants' experience from both individual counselling and group sessions with tools to strengthen self-care; "Staff who know how," based on experience from the meeting with, and the importance of, competent health professionals; "Why feedback is essential," based on the participants' experience and effects of person-centered feedback. Several factors were deemed important in the structure of the program: an individual visit with shared goal setting, a group education session with interactive discussion, a competent, educated, and respectful health professional who gives continuous feedback, and the right tools to support self-care at home between visits.

    CONCLUSION: Individuals participating in a structured lifestyle program experienced several factors as important: an individual visit with shared goal setting, a group education session with interactive discussion, a competent, educated, and respectful healthcare professional who gives continuous feedback, and the right tools to support self-care at home between visits.

  • 332.
    Lidin, Matthias
    et al.
    Karolinska institutet.
    Hellénius, Mai-Lis
    Karolinska institutet.
    Rydell-Karlsson, Monica
    Karolinska institutet.
    Ekblom Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Long-term effects on cardiovascular risk of a structured multidisciplinary lifestyle program in clinical practice.2018Ingår i: BMC Cardiovascular Disorders, ISSN 1471-2261, E-ISSN 1471-2261, Vol. 18, nr 1, artikel-id 59Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Cardiovascular disease is still the leading cause of premature death world-wide with factors like abdominal obesity, hypertension and dyslipidemia being central risk factors in the etiology. The aim of the present study was to investigate the effects on cardiovascular risk factors and cardiovascular risk after 6 months and 1 year, in individuals with increased cardiovascular risk enrolled in a lifestyle multidisciplinary program in a clinical setting.

    METHOD: Individuals with increased cardiovascular risk were referred from primary health care and hospitals to a program at an outpatient clinic at a department of cardiology. The program consisted of three individual visits including a health check-up with a physical examination and blood sampling, and a person-centered dialogue for support in behavioural change of unhealthy lifestyle habits (at baseline, 6 months and 1 year). Furthermore, five educational group sessions were given at baseline. Cardiovascular risk was assessed according to Framingham cardiovascular risk predicting model.

    RESULTS: One hundred individuals (mean age 59 years, 64% women) enrolled between 2008 and 2014 were included in the study. Waist circumference, systolic and diastolic blood pressure and total cholesterol decreased significantly over 1 year. In parallel, cardiovascular risk according to the cardiovascular risk profile based on Framingham 10-year risk prediction model, decreased with 15%. The risk reduction was seen in both men and women, and in participants with or without previous cardiovascular disease.

    CONCLUSION: Participating in a structured lifestyle program over a year was associated with significant improvement in multiple cardiovascular risk factors and decreased overall cardiovascular risk.

    TRIAL REGISTRATION: The study is registered at www.clinicaltrials.gov (ClinicalTrial.gov ID: NCT02744157 ).

  • 333.
    Lilja, Mats
    et al.
    Karolinska institutet.
    Mandić, Mirko
    Karolinska institutet.
    Apró, William
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Melin, Michael
    Karolinska institutet.
    Olsson, Karl
    Karolinska institutet.
    Rosenborg, Staffan
    Karolinska institutet.
    Gustafsson, Thomas
    Karolinska institutet.
    Lundberg, Tommy R
    Karolinska institutet.
    High-doses of anti-inflammatory drugs compromise muscle strength and hypertrophic adaptations to resistance training in young adults.2018Ingår i: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 222, nr 2, artikel-id e12948Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AIMS: This study tested the hypothesis that high doses of anti-inflammatory drugs would attenuate the adaptive response to resistance training compared with low doses.

    METHODS: Healthy men and women (aged 18-35 years) were randomly assigned to daily consumption of ibuprofen (IBU; 1200 mg; n=15) or acetylsalicylic acid (ASA; 75 mg; n=16) for 8 weeks. During this period, subjects completed supervised knee-extensor resistance training where one leg was subjected to training with maximal volitional effort in each repetition using a flywheel ergometer (FW), while the other leg performed conventional (work-matched across groups) weight-stack training (WS). Before and after training, muscle volume (MRI) and strength were assessed, and muscle biopsies were analysed for gene and protein expression of muscle growth regulators.

    RESULTS: The increase in m. quadriceps volume was similar between FW and WS, yet was (averaged across legs) greater in ASA (7.5%) compared with IBU (3.7%, group difference 34 cm(3) ; P=0.029). In the WS leg, muscle strength improved similarly (11-20%) across groups. In the FW leg, increases (10-23%) in muscle strength were evident in both groups yet they were generally greater (interaction effects P<0.05) for ASA compared with IBU. While our molecular analysis revealed several training effects, the only group interaction (P<0.0001) arose from a down-regulated mRNA expression of IL-6 in IBU.

    CONCLUSION: Maximal over-the-counter doses of ibuprofen attenuate strength and muscle hypertrophic adaptations to 8 weeks of resistance training in young adults. Thus, young individuals using resistance training to maximise muscle growth or strength should avoid excessive intake of anti-inflammatory drugs. This article is protected by copyright. All rights reserved.

  • 334.
    Lilja, Mats
    et al.
    Karolinska Institutet.
    Moberg, Marcus
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Mandić, Mirko
    Karolinska Institutet.
    Gustafsson, Thomas
    Karolinska Institutet.
    Lundberg, Tommy R.
    Karolinska Institutet.
    High versus Low doses of Anti-inflammatory Drugs Do Not Differentially Affect Muscle Molecular Response to Acute Resistance Exercise: 2008 Board #269 May 31 2:00 PM - 3:30 PM.2018Ingår i: Medicine & Science in Sports & Exercise. 2018 Supplement 1, Vol. 50, p488-488, 2018, Vol. 50, s. 488-488Konferensbidrag (Övrigt vetenskapligt)
  • 335. Lindegård, Agneta
    et al.
    Jonsdottir, Ingibjörg H
    Börjesson, Mats
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Lindwall, Magnus
    Gerber, Markus
    Changes in mental health in compliers and non-compliers with physical activity recommendations in patients with stress-related exhaustion.2015Ingår i: BMC Psychiatry, ISSN 1471-244X, E-ISSN 1471-244X, Vol. 15, artikel-id 272Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: There is a lack of research regarding the long-lasting effects of a more physically active lifestyle in patients with mental disorders. In the present study, clinical data were analysed to examine if initially physically inactive patients, clinically diagnosed with stress-related exhaustion, taking part in 12-month multimodal treatment (MMT), differ at the 18-month follow-up regarding mental health, depending on whether they did or did not comply with the physical activity (PA) recommendations resembling those of the American College of Sports Medicine.

    METHODS: The study population consisted of 69 patients (65 % women) who were referred to a stress clinic due to stress-related exhaustion. All patients received MMT. A major goal was to increase patients' PA levels. The patients received general comprehensive instructions including personal advice regarding the positive effects of PA on mental health and could self-select for an 18-week coached exercise program. Changes in mental health symptoms over an 18-month period were compared between non-compliers (n = 26), mild compliers (n = 22) and strong compliers (n = 21) with the PA recommendations included in the MMT.

    RESULTS: Non-compliers, mild and strong compliers did not differ regarding burnout, depression and anxiety at baseline. Although substantial improvements occurred in all groups, mild and strong compliers reported significantly lower burnout and depression levels at the 18-month follow-up than the non-complying group (p < .05). The general pattern of findings was corroborated, if standard cut-off criteria for clinical burnout were used.

    CONCLUSIONS: Compliance with PA recommendations is associated with decreased levels of burnout and depression in patients with stress-related exhaustion. Thus, the promotion of a more active lifestyle among patients with stress-related exhaustion should be implemented as a part of MMT, to achieve a more sustainable decrease of symptoms of burnout and depression.

    TRIAL REGISTRATION: This is not a clinical trial.

  • 336.
    Lindgren, Martin
    et al.
    Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra.
    Börjesson, Mats
    Department of Food, Nutrition and Sports Science, Institute of Neuroscience and Physiology, Sahlgrenska Academy and, Sahlgrenska University Hospital/Östra.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Bergström, Göran
    Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra.
    Lappas, Georgios
    Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra.
    Rosengren, Annika
    Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital/Östra.
    Physical activity pattern, cardiorespiratory fitness, and socioeconomic status in the SCAPIS pilot trial — A cross-sectional study2016Ingår i: Preventive Medicine Reports, ISSN 0350-1159, E-ISSN 2211-3355, Vol. 4, s. 44-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Living in a low socioeconomic status (SES) area is associated with an increased risk of cardiovascular events and all-cause mortality. Previous studies have suggested a socioeconomic gradient in daily physical activity (PA), but have mainly relied on self-reported data, and individual rather than residential area SES. This study aimed to investigate the relationships between residential area SES, PA pattern, compliance with PA-recommendations and fitness in a Swedish middle-aged population, using objective measurements. We included 948 individuals from the SCAPIS pilot study (Gothenburg, Sweden, 2012, stratified for SES, 49% women, median age: 58years), in three low and three high SES districts. Accelerometer data were summarized into intensity-specific categories: sedentary (SED), low (LIPA), and medium-to-vigorous PA (MVPA). Fitness was estimated by submaximal ergometer testing. Participants of low SES areas had a more adverse cardiovascular disease risk factor profile (smoking: 20% vs. 6%; diabetes: 9% vs. 3%; hypertension: 38% vs. 25%; obesity: 31% vs. 13%), and less frequently reached 150min of MVPA per week (67% vs. 77%, odds ratio [OR]=0.61; 95% confidence interval [95% CI]=0.46–0.82), from 10-minute bouts (19% vs. 31%, OR=0.53, 95% CI=0.39–0.72). Individuals in low SES areas showed lower PA levels (mean cpm: 320 vs. 348) and daily average MVPA (29.9 vs. 35.5min), and 12% lower fitness (25.1 vs. 28.5mL×min−1×kg−1) than did those in high SES areas. Reduced PA and fitness levels may contribute to social inequalities in health, and should be a target for improved public health in low SES areas.

  • 337. Lindwall, Magnus
    et al.
    Gerber, Markus
    Jonsdottir, Ingibjörg H
    Börjesson, Mats
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Ahlborg, Gunnar
    The relationships of change in physical activity with change in depression, anxiety, and burnout: A longitudinal study of Swedish healthcare workers.2014Ingår i: Health Psychology, ISSN 0278-6133, E-ISSN 1930-7810, Vol. 33, nr 11, s. 1309-1318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: The purpose of the present study was to examine whether intraindividual changes in physical activity were correlated with intraindividual changes in mental health (depression, anxiety, and burnout) across four measurement time-points over 6 years, both from between-person and within-person perspectives. Methods: Health care workers (N = 3717; mean age = 46.9; SD = 10.0) were the target population in this study, which is part of a larger longitudinal survey that included questionnaires on physical activity levels and mental health (depression, anxiety, and burnout) at four time points across 6 years (2004-2010). Physical activity was assessed with an adapted version of the widely used 1-item, 4-level Saltin Grimby Physical Activity Level Scale (SGPALS). Depression, anxiety, and burnout were assessed using the Hospital Anxiety and Depression (HAD) scale and the Shirom-Melamed Burnout Questionnaire (SMBQ). Bivariate latent growth curve models were used to analyze the associations of change between physical activity and mental health. Results: Baseline levels of physical activity were moderately associated with baseline levels of mental health (rs = -.27 to -.40, ps < .01). Changes in physical activity were moderately to strongly associated (rs = -.57 to -.79, ps <. 01) with change in mental health at the between-person (correlated change) level and significantly, but weakly (rs = -.08 to -.14, ps <.01), associated with change at the within-person (coupled change) level of analysis. Conclusions: Changes in physical activity were associated with, and traveled together with, changes in depression, anxiety, and burnout across time. Changes in physical activity, and not only current or previous levels of activity, may be important to consider in preventive work linked to mental health within this population. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  • 338.
    Lundvall, Suzanne
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Schantz, Peter
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    200 years of physical education teacher education: An overview of movement practices2016Ingår i: Researching Embodied Sport: Exploring Movement Cultures / [ed] Ian Wellard, Oxon, England: Routledge, 2016, s. 30-46Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 339.
    Lundvall, Suzanne
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Schantz, Peter
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, FoU-gruppen för rörelse, hälsa och miljö.
    A 200-year perspective and future challenges: Physical activities and their relation to physical education2013Ingår i: Gender In Physical Culture The 2013 Meeting: Transnational working group for the study of gender and sport, 2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Over time the chosen bodily movement practices within Physical education and health (PEH) have created tensions in terms of power and control over what has been seen as legitimate in the educational sector of physical culture. The aim of the study has been to, through a macro level overview and by using a model, illuminate how different bodily movement practices in the world’s oldest physical education teacher education (PETE) have emerged over time, become embedded, remain, fade or disappear. By following this continuity and discontinuity of practices, four distinct phases have been identified and their contextual background is described.

    The theoretical departure point is inspired by the work of Bourdieu. The analytical focus have been placed on how deliberate forms of bodily movement practices within the studied PETE program came to be defined and regulated through meaning making principles, or in other words: logic of practices (Bourdieu 1984, 1990). This departure point makes it possible to analyze how aspects of investment and intrinsic values have been put forward and related to views on body, gender and health.

    Findings: The first phase is characterized by the establishment of Ling gymnastics from early 1800s, and its gradual fall in the 1900s. Next phase started in the late 1800s and dealt with the introduction of sport and outdoor life. The third relates to the rise and fall of a separate female gymnastics practice during the 1900s. The fourth phase is characterized by the introduction of everyday life physical activities in the beginning of the new millennium. The overview is followed by reflections on the future content of bodily movement practices and sought for values in PETE and physical education in the school system, seen from a gender perspective.

  • 340.
    Lundvall, Suzanne
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Forskningsgruppen för pedagogik, idrott och fritidskultur.
    Schantz, Peter
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Physical Activities and Their Relation to Physical Education: A 200-Year Perspective and Future Challenges2013Ingår i: The Global Journal of Health and Physical Education Pedagogy, ISSN 2160-2570, Vol. 2, nr 1, s. 1-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this macrolevel overview, a model of the multiplicity of the field of bodily movement cultures is initially presented. The model is then used to illuminate how different bodily movement practices emerged over time, became embedded, remained, faded, or disappeared in the world’s oldest physical education teacher education (PETE) program. Through thiscontinuity and discontinuity of practices, five distinct phases are identified, although sometimes intertwined, and their contextual background is described. The first phase is characterized by the establishment of Ling gymnastics from the early 19thcentury and by its fall in the 20thcentury. The next phase started in the late 19thcentury and dealt with the introduction of sportsand outdoor life. During a third phase, sports became the dominating movement practice. The fourth phase is related to the rise and fall of a separate female gymnastics culture during the 20thcentury. The fifth phase is characterized by the introduction of everyday life physical activities at the beginning of the new millennium. The overview is followed by reflections on the future content of bodily movement practices and sought-after values in PETE and physical education in the school system.

  • 341. Löllgen, H.
    et al.
    Börjesson, Mats
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms och Mats Börjessons forskningsgrupp.
    Cummiskey, J.
    Bachl, N.
    Debruyne, A.
    The Pre-Participation Examination in Sports: EFSMA Statement on ECG for Pre-Particpation Examination: Die sportärztliche Vorsorgeuntersuchung : Stellungnahme der EFSMA zur Bedeutung des EKG in der Vorsorgeuntersuchung2015Ingår i: Deutsche Zeitschrift für Sportmedizin, ISSN 0344-5925, Vol. 66, nr 6, s. 151-155Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Goals of pre-participation examination (PPE) in athletes are primarily to protect health of athletes. This applies for children, adolescents, leisure time and top athletes. To recognise early possible risks, history and clinical examination is agreed to be the basis of PPE. However, there is a long-standing  controversy about whether ECG at rest should also be mandatory for all athletes. ECG is rejected in the US but included in most European countries.

    In addition, some large sports organisations also require ECG in PPE of athletes. The resting ECG can detect potential life-threatening diseases such as cardiomyopathies or ion-channel diseases ,thus avoiding sudden cardiac events or even death. The present paper discusses many arguments pro and contra ECG in athlete's screening. Arguments against are organisational problems, as sports physicians are not present nationwide in the US. Main arguments against are the lack of large prospective studies demonstrating reduced mortality by ECG, and the low sensitivity, specificity and predictive values of the ECG.

    However, current studies, new stringent and reliable criteria for ECG interpretation (e.g. Seattle criteria) increased the validity: false positive and negative findings decrease significantly. This is also supported by new, athlete-related ECG interpretation software in ECG devices, which are more reliable than visual analysis. This also may reduce legal problems, whereas psychological problems are of low importance as has been shown recently. Therefore, ECG recording in all athletes is strongly recommended in Europe. ECG is superior to history and clinical exam in detecting hidden and congenital diseases.

    However, special education in sports cardiology is advised, courses and training in ECG interpretation in athletes, as well as special ECG devices are mandatory for correct ECG interpretation in athletes.

  • 342.
    Lönnberg, Lena
    et al.
    Uppsala University, Sweden..
    Ekblom Bak, Elin
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Björn Ekbloms forskningsgrupp.
    Damberg, Mattias
    Uppsala University, Sweden..
    Improved unhealthy lifestyle habits in patients with high cardiovascular risk: results from a structured lifestyle programme in primary care2019Ingår i: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 124, nr 2, s. 94-104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background. Physical activity, healthful dietary habits, and not smoking are associated with reduced cardiovascular morbidity and mortality. However, few studies have examined how counselling to improve poor lifestyle habits might be carried out in clinical practice. In Swedish primary care, structured lifestyle counselling is still not integrated into everyday clinical practice. The aim of the present study was two-fold: (1) to describe a novel lifestyle intervention programme in primary care; and (2) to evaluate change in unhealthy lifestyle habits over 1 year in men and women with high cardiovascular risk who participated in the lifestyle intervention programme. Method. A single-group study with a 1-year follow-up was carried out. A total of 417 people was enrolled, median age 62 years (54% women), with either hypertension (69%), type 2 diabetes mellitus, or impaired glucose tolerance. The 1-year intervention included five counselling sessions that focused on lifestyle habits, delivered by a district nurse with postgraduate credits in diabetes care and the metabolic syndrome. All patients were offered in-depth counselling for one or more lifestyle habits when needed. Lifestyle habits were assessed by a questionnaire at baseline and 1-year follow-up. Total change was assessed using a nine-factor unhealthy lifestyle habit index. Results. Favourable, significant changes were observed for physical activity, dietary habits, smoking, and stress over 1 year. Similar improvements were seen for both sexes and type of diagnosis. Conclusions. The results support the utility of a multifactorial, structured approach to change unhealthy lifestyle habits for cardiovascular risk prevention in a primary care setting.

  • 343. Lövenheim, Boel
    et al.
    Johansson, Christer
    Wahlgren, Lina
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö. Riksidrottsförbundet.
    Rosdahl, Hans
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Salier Eriksson, Jane
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Schantz, Peter
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, FoU-gruppen för rörelse, hälsa och miljö.
    Almström, Peter
    Berglund, Svante
    Markstedt, Anders
    Nilsson Sommar, Johan
    Forsberg, Bertil
    Health risk assessment of reduced air pollution exposure when changing commuting by car to bike2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this study we have assessed the reduction in traffic emissions and population exposure assuming all potential car commuters would switch to biking if they live within 30 minute travel by bike. The scenario would result in more than 100 000 new bikers and due to the reduced traffic emissions 42 premature deaths would be avoided per year. This is almost twice as large effect as the congestion tax in Stockholm.

     

     

    Introduction

    Regular physical activity has important and wide-ranging health benefits including reduced risk of chronic disease, and physical inactivity is mentioned as perhaps the most important public health problem of the 21st century. At the same time, the direct effects of traffic emissions is a major health problem. Transferring commuting by car to bike will increase physical activity and reduce emissions and reduce population exposure to traffic pollution. The exposure of commuters will also change; new bikers may get higher exposure whilst old bikers and car drivers may get lower exposures, depending on commuting route and distance.

     

    Methodology

    In this study we have calculated the potential number of car-to-bike switching commuters depending on distance, travel time, age of commuters, etc. We have made calculations for a 30-minute biking scenario, i.e. transferring all car commuters to bike if their travel time by bike is less than or equal to 30 minutes. The commuting distance depends on age and sex. For the travel and traffic modelling the LuTrans model was used. It includes all different modes of travel; walking, bicycling, public transport systems and car traffic. The model was developed based on travel survey data and is regularly calibrated using traffic counts. Emissions from road traffic were calculated based on HBEFA 3.2. A Gaussian dispersion model was used estimate exposures over the county of Stockholm.

     

    Results

    The 30 min scenario resulted in 106 881 more bikers, an increase of 2.6 times compared to base scenario. Of all bikers 50% were men and the mean age of all bikers was 42. The traffic emissions of NOx was reduced by up to 7%. Up to 20% reduction in traffic contribution to NOx concentrations was calculated as shown in Figure 1. The mean reduction in concentration for the whole area is 6% and the largest occur were most people live.

    The population weighted mean NOx concentration for 1.6 million people in Greater Stockholm is estimated to be reduced by 0.41 μg m-3. Assuming that the premature mortality is reduced by 8% per 10 μg m-3 (Nafstad et al., 2004), this corresponds to 42 avoided premature deaths every year or 514 gained life years gained. This is even somewhat more beneficial than the effects of the congestion charge in Stockholm (Johansson et al., 2009), which was estimated to save 27 premature deaths per year. The gain in reduced mortality is almost as large as the gain in health of the increased physical activity.

     

    Conclusions

    Transferring car commuters to bike is not only beneficial for the physical activity, but will also lead to reduced traffic emissions and reduced population exposure. Our estimates show that it may be even more beneficial for mortality due to air pollution exposure than the congestion charge in Stockholm.

     

    Acknowledgement

    This project was funded by the Swedish Research Council for Health, Working life and Welfare.

     

    References

    Johansson, C., Burman, L., Forsberg, B. 2009. The effects of congestions tax on air quality and health. Atmos. Environ. 43, 4843-4854.

    Nafstad, P., Lund Håheim, L., Wisloeff, T., Gram, G., Oftedal, B., Holme, I., Hjermann, I. and Leren, P. 2004. Urban Air Pollution and Mortality in a Cohort of Norwegian Men. Environ. Health Perspect. 112, 610-615.

  • 344. Malm, Christer
    et al.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Immune system alteration in response to increased physical training during a five day soccer training camp.2004Ingår i: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 25, nr 6, s. 471-6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Leukocyte and monocyte subpopulations were investigated in ten elite male soccer players before and after a 5-day training camp. It was hypothesized that with increased training intensity and duration, the immune system would show signs of depression. Blood samples were taken at rest before and after the training camp and cell surface antigens were investigated by four-colour flow cytometry. After five days of intensified training, there was a significant decrease in the number of T helper, T cytotoxic and B cells, the expression of CD11 b on leukocytes increased and the NK cell population did not change significantly. It is concluded that after a period of intensified training, soccer players may experience decreased T and B cell numbers in circulation, possibly affecting their capability to activate the immune system and resist infections. However, in contrast to the acute decrease in the number of circulating NK cells commonly observed after physical exercise, no change in this cell population was observed at rest after a period of intensified physical training. Exercise-induced immunological changes were highly differentiated between different leukocyte subpopulations.

  • 345. Malm, Christer
    et al.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Immune system alteration in response to two consecutive soccer games.2004Ingår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 180, nr 2, s. 143-55Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    AIM: Changes in leucocyte and monocyte subpopulations were investigated in 10 elite male soccer players aged 16-19 years. The purpose was to perform a descriptive study of immunological alterations in elite soccer players in response to two consecutive games separated by 20 h. It was hypothesized that in response to two games the players would show signs of short-term immunosuppression. METHODS: Blood samples were taken before the first soccer game, immediately after the second game and after 6, 24, 48 and 72 h. Cell surface antigens, testosterone and cortisol were investigated. RESULTS: During the first 6 h after the second game there was a significant increase in number of circulating neutrophils, mature (CD20+ CD5+) B cells and CD4/CD8 ratio. A significant decrease was observed in the number of natural killer (NK) cells, monocytes and adhesion on lymphocytes and monocytes. In a delayed phase, 48 h after the second game the expression of both adhesion and signalling molecules increased on lymphocytes and monocytes. Changes in adhesion and signalling molecules at 48 h correlated negatively to the subjects VO2max, suggesting larger immunological response to similar exercise in subjects with lower aerobic exercise capacity. CONCLUSION: In response to competitive soccer exercise some immunological variables are enhanced while others are depressed. Observed changes may serve a purpose in adaptation to exercise by signalling via adhesion.

  • 346. Malm, Christer
    et al.
    Ekblom, Örjan
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Immunological Alterations Used to Predict Infections in Response to Strenuous Physical Training2011Ingår i: Military medicine, ISSN 0026-4075, E-ISSN 1930-613X, Vol. 176, nr 7, s. 785-790Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ABSTRACT The aim of this study was to screen leukocyte cell surface markers to identify possible predictors for infection related to physical training. Ten healthy soldiers (mean age, 19.1; mean body mass, 77.4 kg; mean VO ^sub 2^ peak, 4.54 L min ^sup -1^ /58.6 mL min ^sup -1^ kg ^sup -1^ ) were included. Blood samples were collected and number of infections recorded before and after a 6-day training course. White blood cell distributions and expression of surface receptors changed during training. Before training, expression of CD3 on CD8  lymphocytes and percent CD8 CD3 lymphocytes was lower, whereas CD4/CD8 ratio was higher among subjects who failed compared to those who completed the training. A subclinical infection before the start of the military training may alter the CD4/CD8 ratio. Prediction of future infections may be possible from pre-exercise immunological status, fi ndings useful in military settings and exercise, where sudden infections may result in severe consequences.  

  • 347. Malm, Christer
    et al.
    Sjödin, The Late Bertil
    Sjöberg, Berit
    Lenkei, Rodica
    Renström, Per
    Lundberg, Ingrid E
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running.2004Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 556, nr Pt 3, s. 983-1000Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Muscular adaptation to physical exercise has previously been described as a repair process following tissue damage. Recently, evidence has been published to question this hypothesis. The purpose of this study was to investigate inflammatory processes in human skeletal muscle and epimysium after acute physical exercise with large eccentric components. Three groups of subjects (n= 19) performed 45 min treadmill running at either 4 deg (n= 5) or 8 deg (n= 9) downhill or 4 deg uphill (n= 5) and one group served as control (n= 9). One biopsy was taken from each subject 48 h post exercise. Blood samples were taken up to 7 days post exercise. Compared to the control group, none of the markers of inflammation in muscle and epimysium samples was different in any exercised group. Only subjects in the Downhill groups experienced delayed onset of muscle soreness (DOMS) and increased serum creatine kinase activity (CK). The detected levels of immunohistochemical markers for T cells (CD3), granulocytes (CD11b), leukaemia inhibitory factor (LIF) and hypoxia-inducible factor 1beta (HIF-1beta) were greater in epimysium from exercised subjects with DOMS ratings >3 (0-10 scale) compared to exercised subjects without DOMS but not higher than controls. Eccentric physical exercise (downhill running) did not result in skeletal muscle inflammation 48 h post exercise, despite DOMS and increased CK. It is suggested that exercise can induce DOMS by activating inflammatory factors present in the epimysium before exercise. Repeated physical training may alter the content of inflammatory factors in the epimysium and thus reduce DOMS.

  • 348. Mandroukas, A
    et al.
    Heller, J
    Metaxas, T I
    Christoulas, K
    Vamvakoudis, E
    Stefanidis, P
    Papavasileiou, A
    Kotoglou, K
    Balasas, D
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Mandroukas, K
    Deltoid muscle characteristics in wrestlers.2010Ingår i: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 31, nr 3, s. 148-53Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 349. Mandroukas, A
    et al.
    Metaxas, T
    Kesidis, N
    Christoulas, K
    Vamvakoudis, E
    Stefanidis, P
    Heller, J
    Ekblom, Björn
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Björn Ekbloms forskningsgrupp.
    Mandroukas, K
    Deltoid muscle fiber characteristics in adolescent and adult wrestlers.2010Ingår i: Journal of Sports Medicine and Physical Fitness, ISSN 0022-4707, E-ISSN 1827-1928, Vol. 50, nr 2, s. 113-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 350.
    Manselin, Tom A
    et al.
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Södergård, Olof
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet.
    Larsen, Filip J
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Lindholm, Peter
    Karolinska institutet.
    Aerobic efficiency is associated with the improvement in maximal power output during acute hyperoxia.2017Ingår i: Physiological Reports, E-ISSN 2051-817X, Vol. 5, nr 2, artikel-id e13119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

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