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Salier Eriksson, J., Ekblom, B., Kallings, L., Hemmingsson, E., Andersson, G., Wallin, P., . . . Ekblom Bak, E. (2019). Active commuting in Swedish workers between 1998 and 2015 - trends, characteristics and cardiovascular disease risk.. Scandinavian Journal of Medicine and Science in Sports
Open this publication in new window or tab >>Active commuting in Swedish workers between 1998 and 2015 - trends, characteristics and cardiovascular disease risk.
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2019 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838Article in journal (Refereed) Epub ahead of print
Abstract [en]

BACKGROUND: Trend analyses of active commuting and potential variations in trends and association with cardiovascular disease (CVD) risk within sub-groups are unknown.

OBJECTIVES: To a) describe trends in active commuting between 1998 to 2015 and b) to study the association between different amounts of active commuting and the incidence risk of CVD in a large sample of Swedish workers, and analyses of potential variations across sub-groups of socio-demographics, physical activity and BMI.

METHODS: A total of 318,309 participants (47% women, 18-74 years) who participated in a nationwide occupational health service screening between 1998 and 2015 were included. Commuting habits were self-reported, and data on first-time CVD events were derived from national registers.

RESULTS: Self-reported passive commuters decreased between 1998 and 2015 (64% to 56%), transferring to an increase in mainly moderate/high-dose active commuters (12% to 19%). Changes were seen in all subgroups. The characteristics and life-style habits of the typical passive and active commuter changed little over the study period. Low- and moderate/high-dose active commuters had significantly decreased risks for a first time CVD during follow-up. This was accentuated in men, middle-aged and in participants with light physical work situations, irregular exercise habits, being overweight/obese and with low fitness.

CONCLUSION: Increases in active commuting were observed between 1998 and 2015, however still leaving a majority who do not actively commute. As active commuting, regardless dose, is associated with a lower CVD risk, encouraging more people to actively commute may provide an easily accessible and time-efficient possibility to increase physical activity and health in the general population.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
active commuting, cardiovascular disease, cycling, physical activity, trends, walking, working population
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5889 (URN)10.1111/sms.13581 (DOI)000499749900001 ()31631386 (PubMedID)
Projects
HPI-gruppen
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-12-18Bibliographically approved
Nilsson, L., Flockhart, M., Apro, W., Ekblom, B. & Larsen, F. J. (2019). Biphasic relationship between training load and glucose tolerance. In: : . Paper presented at Cell Symposia, Exercise Metabolism. May 5-7 2019, Sitges Spain.
Open this publication in new window or tab >>Biphasic relationship between training load and glucose tolerance
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [sv]

Biphasic relationship between training load and glucose tolerance

Nilsson, L, Flockhart M, Bergman K, Apro W, Ekblom B, Larsen FJ

 

There is a well-established construct regarding the positive effects of exercise on glucose tolerance and insulin sensitivity, as well as muscle glycogen storage. In insulin resistance, physical activity is an essential part of the treatment. However, the optimal dose is unknown. Reduced muscular glycogen stores, resulting from exercise, should stimulate an increased uptake of blood glucose. In this study we investigated the relation between training load, glucose tolerance and insulin sensitivity during three weeks of increasing interval training. Three times during the intervention, oral glucose tests were conducted to investigate the rate of glucose uptake. We found a biphasic dose-response relationship between training load and glucose tolerance, where an excessive training load led to a paradoxical reduction in glucose tolerance and impaired insulin release despite an unchanged amount of muscle glycogen. In light of these results, an upper limit of physical exercise exist where the negative effects overpowers the positive.

National Category
Cell Biology
Research subject
Medicine/Technology; Medicine/Technology; Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5933 (URN)
Conference
Cell Symposia, Exercise Metabolism. May 5-7 2019, Sitges Spain
Funder
Swedish National Centre for Research in Sports
Available from: 2019-11-29 Created: 2019-11-29 Last updated: 2019-12-09Bibliographically approved
Metaxas, T., Mandroukas, A., Michailidis, Y., Koutlianos, N., Christoulas, K. & Ekblom, B. (2019). Correlation of Fiber-Type Composition and Sprint Performance in Youth Soccer Players.. Journal of Strength and Conditioning Research, 33(10), 2629-1634
Open this publication in new window or tab >>Correlation of Fiber-Type Composition and Sprint Performance in Youth Soccer Players.
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2019 (English)In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 33, no 10, p. 2629-1634Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to examine the correlation between muscle fiber type and sprint performance in elite young soccer players of different age groups of the same team. Twenty-eight young players participated in this study (group U15, n = 8; group U13, n = 9; and group U11, n = 11). Anthropometric assessments, acceleration (10 m), and Bangsbo modified sprint test (30 m) were performed. Muscle biopsies were obtained from the vastus lateralis, and after that, fiber-type composition was determined by immunohistochemistry. No significant correlations were found between the sprint test and muscle fiber distribution for the groups U13 and U11 (p > 0.05). Also, no correlations were found between cross-sectional areas in the types of fibers with the sprint test in all groups (p > 0.05). A positive correlation was found between type I fibers and the performance in the acceleration test (10 m) (r = 0.77, p < 0.05) was found only in group U15 and a negative correlation between type IIA fibers and the performance in the acceleration test (10 m) (r = -0.89, p < 0.05). The correlations were observed only in group U15, which may indicate that the duration and the intensity of the soccer systematic training can affect the plasticity of the muscle fibers. Specific soccer training in youth is one of the factors that can affect fiber-type plasticity. The specific training programs and status of U15 are more intensive, and the exercises are oriented more to improve physical fitness.

Place, publisher, year, edition, pages
Wolters Kluwer, 2019
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5859 (URN)10.1519/JSC.0000000000003320 (DOI)000505956100007 ()31403577 (PubMedID)
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2020-01-16Bibliographically approved
Ekblom Bak, E., Ekblom, Ö., Andersson, G., Wallin, P., Söderling, J., Hemmingsson, E. & Ekblom, B. (2019). Decline in cardiorespiratory fitness in the Swedish working force between 1995 and 2017.. Scandinavian Journal of Medicine and Science in Sports, 29(2), 232-239
Open this publication in new window or tab >>Decline in cardiorespiratory fitness in the Swedish working force between 1995 and 2017.
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2019 (English)In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 29, no 2, p. 232-239Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Long-term trend analyses of cardiorespiratory fitness (VO2 max) in the general population are limited.

OBJECTIVES: To describe trends in VO2 max from 1995 to 2017 in the Swedish working force and to study developments across categories of sex, age, education, and geographic regions.

METHODS: 354.277 participants (44% women, 18-74 years) who participated in a nationwide occupational health service screening between 1995 and 2017 were included. Changes in standardized mean values of absolute (L·min-1 ) and relative (ml·min-1 ·kg-1 ) VO2 max, and the proportion with low (<32) relative VO2 max are reported. VO2 max was estimated using a submaximal cycle test.

RESULTS: Absolute VO2 max decreased by -6.7% (-0.19 L·min-1 ) in the total population. Relative VO2 max decreased by -10.8% (-4.2 ml·min-1 ·kg-1 ) with approximately one-third explained by a simultaneous increase in body mass. Decreases in absolute fitness were more pronounced in men vs. women (8.7% vs. 5.3%), in younger vs. older (6.5% vs 2.3%), in short (11.4%) vs. long (4.5%) education, and in rural vs. urban regions (6.5% vs 3.5%), all p<0.001. The proportions with low VO2 max increased from 27% to 46% (p<0.001).

CONCLUSION: Between 1995 and 2017, there was a steady and pronounced decline in mean cardiorespiratory fitness in Swedish adults. Male gender, young age, short education and living in a rural area were predictive of greater reductions. The proportion with low cardiorespiratory fitness almost doubled. Given the strong associations between cardiorespiratory fitness and multiple morbidities and mortality, preventing further decreases is a clear public health priority, especially for vulnerable groups. This article is protected by copyright. All rights reserved.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
Maximal oxygen consumption, VO2max, aerobic capacity, population, secular trend
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5460 (URN)10.1111/sms.13328 (DOI)30351472 (PubMedID)
Projects
HPI-gruppen
Available from: 2018-10-31 Created: 2018-10-31 Last updated: 2019-01-18Bibliographically approved
Flockhart, M., Nilsson, L., Apro, W., Ekblom, B. & Larsen, F. J. (2019). Dose-response relationship between exercise load and mitochondrial function. In: : . Paper presented at Cell Symposia: Exercise Metabolism, May 5-7 2019, Sitges Spain.
Open this publication in new window or tab >>Dose-response relationship between exercise load and mitochondrial function
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2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Dose-response relationship between exercise load and mitochondrial function

Flockhart M, Nilsson L, Bergman K, Apro W, Ekblom B, Larsen FJ

A dose-dependent relationship exists between exercise load and muscular adaptation. Mitochondria adapt to the increased ATP-demand by alterations in mass and/or quality. How mitochondrial mass and quality changes as a function of exercise load is not well investigated and we have previously found mitochondrial dysfunction after short-term intensive exercise. We therefore aimed to study mitochondrial function by altering exercise load during a three week interval training regimen to understand the dose-response relationship between exercise load and mitochondrial function. We took four muscle biopsies throughout the study, and as expected, mitochondrial function was positively affected during the first two weeks. After the third week, a dramatic mitochondrial dysfunction was evident as mitochondrial intrinsic respiration was reduced by 26% despite a 32% increase in mitochondrial yield. We hereby present evidence of a striking exercise-induced reduction in mitochondrial function after a period of very intense interval training.

National Category
Cell Biology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5932 (URN)
Conference
Cell Symposia: Exercise Metabolism, May 5-7 2019, Sitges Spain
Funder
Swedish National Centre for Research in Sports
Available from: 2019-11-29 Created: 2019-11-29 Last updated: 2019-12-09Bibliographically approved
Cardinale, D. A., Larsen, F. J., Lindholm, P., Ekblom, B. & Boushel, R. (2019). Effects Of Hyperoxic-Supplemented High Intensity Interval Training On Endurance Performance, Maximal Oxygen Consumption And Mitochondrial Function In Trained Cyclists. In: MEDICINE AND SCIENCE IN SPORTS AND EXERCISE Vol 51(2019):6. Supplement: S, Meeting Abstract: 1753: . Paper presented at Annual Meeting of the American-College-of-Sports-Medicine (ACSM), MAY 28-JUN 01, 2019, Orlando, FL (pp. 463-464). Lippincott Williams & Wilkins, 51(6)
Open this publication in new window or tab >>Effects Of Hyperoxic-Supplemented High Intensity Interval Training On Endurance Performance, Maximal Oxygen Consumption And Mitochondrial Function In Trained Cyclists
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2019 (English)In: MEDICINE AND SCIENCE IN SPORTS AND EXERCISE Vol 51(2019):6. Supplement: S, Meeting Abstract: 1753, Lippincott Williams & Wilkins, 2019, Vol. 51, no 6, p. 463-464Conference paper, Oral presentation with published abstract (Other academic)
Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2019
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5836 (URN)10.1249/01.mss.0000561892.45529.46 (DOI)000481662801604 ()
Conference
Annual Meeting of the American-College-of-Sports-Medicine (ACSM), MAY 28-JUN 01, 2019, Orlando, FL
Available from: 2019-09-17 Created: 2019-09-17 Last updated: 2019-09-17Bibliographically approved
Hirschberg, A. L., Elings Knutsson, J., Helge, T., Godhe, M., Ekblom, M., Bermon, S. & Ekblom, B. (2019). Effects of moderately increased testosterone concentration on physical performance in young women: a double blind, randomised, placebo controlled study. British Journal of Sports Medicine
Open this publication in new window or tab >>Effects of moderately increased testosterone concentration on physical performance in young women: a double blind, randomised, placebo controlled study
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2019 (English)In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480Article in journal (Refereed) Epub ahead of print
Abstract [en]

Objective To investigate the effects of a moderate increase in serum testosterone on physical performance in young, physically active, healthy women.Methods A double blind, randomised, placebo controlled trial was conducted between May 2017 and June 2018 (ClinicalTrials.gov ID: NCT03210558). 48 healthy, physically active women aged 18–35 years were randomised to 10 weeks of treatment with 10 mg of testosterone cream daily or placebo (1:1). All participants completed the study. The primary outcome measure was aerobic performance measured by running time to exhaustion (TTE). Secondary outcomes were anaerobic performance (Wingate test) and muscle strength (squat jump (SJ), counter movement jump (CMJ) and knee extension peak torque). Hormone levels were analysed and body composition assessed by dual energy X-ray absorptiometry.Results Serum levels of testosterone increased from 0.9 (0.4) nmol/L to 4.3 (2.8) nmol/L in the testosterone supplemented group. TTE increased significantly by 21.17 s (8.5%) in the testosterone group compared with the placebo group (mean difference 15.5 s; P=0.045). Wingate average power, which increased by 15.2 W in the testosterone group compared with 3.2 W in the placebo group, was not significantly different between the groups (P=0.084). There were no significant changes in CMJ, SJ and knee extension. Mean change from baseline in total lean mass was 923 g for the testosterone group and 135 g for the placebo group (P=0.040). Mean change in lean mass in the lower limbs was 398 g and 91 g, respectively (P=0.041).Conclusion The study supports a causal effect of testosterone in the increase in aerobic running time as well as lean mass in young, physically active women.

Place, publisher, year, edition, pages
BMJ Publishing Group Ltd, 2019
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5869 (URN)10.1136/bjsports-2018-100525 (DOI)31615775 (PubMedID)
Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-29Bibliographically approved
Psilander, N., Eftestøl, E., Cumming, K. T., Juvkam, I., Ekblom, M., Sunding, K., . . . Gundersen, K. (2019). Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle. Journal of applied physiology, 126(6), 1636-1645
Open this publication in new window or tab >>Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle
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2019 (English)In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 126, no 6, p. 1636-1645Article in journal (Refereed) Published
Abstract [en]

Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 weeks, followed by 20 weeks of detraining (DT) and a 5-week bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volume, and cross-sectional area (CSA). Ultrasound and one repetition of maximum leg extension were performed to determine muscle thickness (MT) and strength. CSA (~17%), MT (~10%), and strength (~20%) increased during T1 in the mem-leg. However, the myonuclear number and fiber volume did not change. MT and CSA returned to baseline values during DT, but strength remained elevated (~60%), supporting previous findings of a long-lasting motor learning effect. MT and strength increased similarly in the mem-leg and con-leg during T2, whereas CSA, fiber volume, and myonuclear number remained unaffected. In conclusion, training response during T2 did not differ between the mem-leg and con-leg. However, this does not discount the existence of human muscle memory since no increase in the number of myonuclei was detected during T1 and no clear detraining effect was observed for cell size during DT; thus, the present data did not allow for a rigorous test of the muscle memory hypothesis.

Place, publisher, year, edition, pages
American Physiological Society, 2019
Keywords
CSA, exercise, motor learning, muscle memory, myonuclei
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5716 (URN)10.1152/japplphysiol.00917.2018 (DOI)000471217500014 ()30991013 (PubMedID)
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-08-14Bibliographically approved
Cardinale, D. A., Larsen, F. J., Lännerström, J., Manselin, T., Södergård, O., Mijwel, S., . . . Boushel, R. (2019). Influence of Hyperoxic-Supplemented High-Intensity Interval Training on Hemotological and Muscle Mitochondrial Adaptations in Trained Cyclists.. Frontiers in Physiology, 10, Article ID 730.
Open this publication in new window or tab >>Influence of Hyperoxic-Supplemented High-Intensity Interval Training on Hemotological and Muscle Mitochondrial Adaptations in Trained Cyclists.
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2019 (English)In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, article id 730Article in journal (Refereed) Published
Abstract [en]

Background: Hyperoxia (HYPER) increases O2 carrying capacity resulting in a higher O2 delivery to the working muscles during exercise. Several lines of evidence indicate that lactate metabolism, power output, and endurance are improved by HYPER compared to normoxia (NORM). Since HYPER enables a higher exercise power output compared to NORM and considering the O2 delivery limitation at exercise intensities near to maximum, we hypothesized that hyperoxic-supplemented high-intensity interval training (HIIT) would upregulate muscle mitochondrial oxidative capacity and enhance endurance cycling performance compared to training in normoxia. Methods: 23 trained cyclists, age 35.3 ± 6.4 years, body mass 75.2 ± 9.6 kg, height 179.8 ± 7.9 m, and VO2max 4.5 ± 0.7 L min-1 performed 6 weeks polarized and periodized endurance training on a cycle ergometer consisting of supervised HIIT sessions 3 days/week and additional low-intensity training 2 days/week. Participants were randomly assigned to either HYPER (FIO2 0.30; n = 12) or NORM (FIO2 0.21; n = 11) breathing condition during HIIT. Mitochondrial respiration in permeabilized fibers and isolated mitochondria together with maximal and submaximal VO2, hematological parameters, and self-paced endurance cycling performance were tested pre- and posttraining intervention. Results: Hyperoxic training led to a small, non-significant change in performance compared to normoxic training (HYPER 6.0 ± 3.7%, NORM 2.4 ± 5.0%; p = 0.073, ES = 0.32). This small, beneficial effect on the self-paced endurance cycling performance was not explained by the change in VO2max (HYPER 1.1 ± 3.8%, NORM 0.0 ± 3.7%; p = 0.55, ES = 0.08), blood volume and hemoglobin mass, mitochondrial oxidative phosphorylation capacity (permeabilized fibers: HYPER 27.3 ± 46.0%, NORM 16.5 ± 49.1%; p = 0.37, ES = 3.24 and in isolated mitochondria: HYPER 26.1 ± 80.1%, NORM 15.9 ± 73.3%; p = 0.66, ES = 0.51), or markers of mitochondrial content which were similar between groups post intervention. Conclusions: This study showed that 6 weeks hyperoxic-supplemented HIIT led to marginal gain in cycle performance in already trained cyclists without change in VO2max, blood volume, hemoglobin mass, mitochondrial oxidative phosphorylation capacity, or exercise efficiency. The underlying mechanisms for the potentially meaningful performance effects of hyperoxia training remain unexplained and may raise ethical questions for elite sport.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
OXPHOS, VO2max, cycling performance, high-intensity interval training, hyperoxia, mitochondria
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5805 (URN)10.3389/fphys.2019.00730 (DOI)000472046700001 ()31258485 (PubMedID)
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Godhe, M., Helge, T., Forsberg, A., Karlsson, E. & Ekblom, B. (2019). Isokinetic muscle torque and endurance in limbs and trunk in children and adolescents: A longitudinal study. Clinical and Medical Investigations, 4(4)
Open this publication in new window or tab >>Isokinetic muscle torque and endurance in limbs and trunk in children and adolescents: A longitudinal study
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2019 (English)In: Clinical and Medical Investigations, ISSN 2398-5763, Vol. 4, no 4Article in journal (Refereed) Published
Abstract [en]

Purpose: To measure isokinetic peak torque during elbow, knee and trunk extension and flexion and muscle endurance during elbow and knee extension.

Method: Muscle endurance and peak torque were measured using Cybex methodology in totally 115 boys and 48 girls from 8 to 15 years of age most of them for five years.

Results: Knee muscle endurance was mainly unchanged while elbow fatigue index was lightly reduced from 11 to 15 years in both sexes with no difference between sexes. From the youngest ages to adolescence peak absolute (N.m) and normalized (N.m/kg body mass) torque increases in all measures with highest increase in the trunk and lowest in elbow activities. During elbow activity boys are stronger than girls from age 11. For trunk and knee activity the sex differences start at age 14 years. Knee, elbow and trunk extension/flexion ratios as well as knee/elbow both extension and flexion ratios are mainly unchanged with increasing age with no differences between sexes.

Conclusion: Data indicate that elbow isokinetic strength and endurance profile is partly different from corresponding data during knee and trunk activity.

Place, publisher, year, edition, pages
OA text, 2019
Keywords
cybex, sex differences, elbow, knee, trunk flexion, extension
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5968 (URN)10.15761/CMI.1000197 (DOI)
Available from: 2019-12-19 Created: 2019-12-19 Last updated: 2019-12-20Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-4030-5437

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