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Nilsson, J., Ekblom, Ö., Ekblom, M., Lebedev, A., Tarassova, O., Moberg, M. & Lövdén, M. (2020). Acute increases in brain-derived neurotrophic factor in plasma following physical exercise relates to subsequent learning in older adults.. Scientific Reports, 10(1), Article ID 4395.
Open this publication in new window or tab >>Acute increases in brain-derived neurotrophic factor in plasma following physical exercise relates to subsequent learning in older adults.
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2020 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 10, no 1, article id 4395Article in journal (Refereed) Published
Abstract [en]

Multidomain lifestyle interventions represents a promising strategy to counteract cognitive decline in older age. Brain-derived neurotrophic factor (BDNF) is essential for experience-dependent plasticity and increases following physical exercise, suggesting that physical exercise may facilitate subsequent learning. In a randomized-controlled trial, healthy older adults (65-75 years) completed a 12-week behavioral intervention that involved either physical exercise immediately before cognitive training (n = 25; 13 females), physical exercise immediately after cognitive training (n = 24; 11 females), physical exercise only (n = 27; 15 females), or cognitive training only (n = 21; 12 females). We hypothesized that cognition would benefit more from cognitive training when preceded as opposed to followed by physical exercise and that the relationship between exercise-induced increases in peripheral BDNF and cognitive training outcome would be greater when cognitive training is preceded by physical exercise. Greater increases of plasma BDNF were associated with greater cognitive training gains on trained task paradigms, but only when such increases preceded cognitive training (ß = 0.14, 95% CI [0.04, 0.25]). Average cognitive training outcome did not differ depending on intervention order (ß = 0.05, 95% CI [-0.10, 0.20]). The study provides the first empirical support for a time-critical but advantageous role for post-exercise increases in peripheral BDNF for learning at an interindividual level in older adults, with implications for future multidomain lifestyle interventions.

Place, publisher, year, edition, pages
Nature Publishing Group, 2020
National Category
Geriatrics
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-6085 (URN)10.1038/s41598-020-60124-0 (DOI)32157099 (PubMedID)
Projects
Träning för äldres hjärnhälsa
Available from: 2020-03-16 Created: 2020-03-16 Last updated: 2020-03-20
Drake, E., Ekblom, M., Ekblom, Ö., Kallings, L. & Blom, V. (2020). Cardiorespiratory Fitness and Device-Measured Sedentary Behaviour are Associated with Sickness Absence in Office Workers.. International Journal of Environmental Research and Public Health, 17(2), Article ID E628.
Open this publication in new window or tab >>Cardiorespiratory Fitness and Device-Measured Sedentary Behaviour are Associated with Sickness Absence in Office Workers.
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2020 (English)In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 17, no 2, article id E628Article in journal (Refereed) Published
Abstract [en]

Physical activity reduces the risk of several noncommunicable diseases, and a number of studies have found self-reported physical activity to be associated with sickness absence. The aim of this study was to examine if cardiorespiratory fitness, device-measured physical activity, and sedentary behaviour were associated with sickness absence among office workers. Participants were recruited from two Swedish companies. Data on sickness absence (frequency and duration) and covariates were collected via questionnaires. Physical activity pattern was assessed using ActiGraph and activPAL, and fitness was estimated from submaximal cycle ergometry. The sample consisted of 159 office workers (67% women, aged 43 ± 8 years). Higher cardiorespiratory fitness was significantly associated with a lower odds ratio (OR) for both sickness absence duration (OR = 0.92, 95% confidence interval (CI) 0.87-0.96) and frequency (OR = 0.93, 95% CI 0.90-0.97). Sedentary time was positively associated with higher odds of sickness absence frequency (OR = 1.03, 95% CI 0.99-1.08). No associations were found for physical activity at any intensity level and sickness absence. Higher sickness absence was found among office workers with low cardiorespiratory fitness and more daily time spent sedentary. In contrast to reports using self-reported physical activity, device-measured physical activity was not associated with sickness absence.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
cardiorespiratory fitness, office workers, physical activity, sedentary behaviour, sickness absence
National Category
Public Health, Global Health, Social Medicine and Epidemiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-6091 (URN)10.3390/ijerph17020628 (DOI)000516827400249 ()31963740 (PubMedID)
Available from: 2020-03-20 Created: 2020-03-20 Last updated: 2020-04-08
Väisänen, D., Ekblom, Ö., Ekblom Bak, E., Andersson, E., Nilsson, J. & Ekblom, M. (2020). Criterion validity of the Ekblom-Bak and the Åstrand submaximal test in an elderly population.. European Journal of Applied Physiology, 120(2), 307-316
Open this publication in new window or tab >>Criterion validity of the Ekblom-Bak and the Åstrand submaximal test in an elderly population.
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2020 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 120, no 2, p. 307-316Article in journal (Refereed) Published
Abstract [en]

PURPOSE: The aim of this study was to validate the submaximal Ekblom-Bak test (EB-test) and the Åstrand test (Å-test) for an elderly population.

METHODS: Participants (n = 104), aged 65-75 years, completed a submaximal aerobic test on a cycle ergometer followed by an individually adjusted indirect calorimetry VO2max test on a treadmill. The HR from the submaximal test was used to estimate VO2max using both the EB-test and Å-test equations.

RESULTS: The correlation between measured and estimated VO2max using the EB method and Å method in women was r = 0.64 and r = 0.58, respectively and in men r = 0.44 and r = 0.44, respectively. In women, the mean difference between estimated and measured VO2max was - 0.02 L min-1 (95% CI - 0.08 to 0.04) for the EB method and - 0.12 L min-1 (95% CI - 0.22 to - 0.02) for the Å method. Corresponding values for men were 0.05 L min-1 (95% CI - 0.04 to 0.14) and - 0.28 L min-1 (95% CI - 0.42 to - 0.14), respectively. However, the EB method was found to overestimate VO2max in men with low fitness and the Å method was found to underestimate VO2max in both women and men. For women, the coefficient of variance was 11.1%, when using the EB method and 19.8% when using the Å method. Corresponding values for men were 11.6% and 18.9%, respectively.

CONCLUSION: The submaximal EB-test is valid for estimating VO2max in elderly women, but not in all elderly men. The Å-test is not valid for estimating VO2max in the elderly.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Cardiorespiratory fitness, Elderly, Oxygen uptake, Public health, Submaximal test, Validity
National Category
Sport and Fitness Sciences
Research subject
Medicine/Technology; Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5960 (URN)10.1007/s00421-019-04275-7 (DOI)000511955700001 ()31820103 (PubMedID)
Available from: 2019-12-18 Created: 2019-12-18 Last updated: 2020-03-20
Hirschberg, A. L., Elings Knutsson, J., Helge, T., Godhe, M., Ekblom, M., Bermon, S. & Ekblom, B. (2020). Effects of moderately increased testosterone concentration on physical performance in young women: a double blind, randomised, placebo controlled study. British Journal of Sports Medicine, 54, 599-604
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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2020 (English)In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 54, p. 599-604Article in journal (Refereed) Published
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, 2020
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: 2020-05-29Bibliographically approved
Horwath, O., Apro, W., Moberg, M., Godhe, M., Helge, T., Ekblom, M., . . . Ekblom, B. (2020). Fiber type-specific hypertrophy and increased capillarization in skeletal muscle following testosterone administration of young women.. Journal of applied physiology, 128(5), 1240-1250
Open this publication in new window or tab >>Fiber type-specific hypertrophy and increased capillarization in skeletal muscle following testosterone administration of young women.
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2020 (English)In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 128, no 5, p. 1240-1250Article in journal (Refereed) Published
Abstract [en]

It is well established that testosterone administration induces muscle fiber hypertrophy and myonuclear addition in men, however, it remains to be determined whether similar morphological adaptations can be achieved in women. The aim of the present study was therefore to investigate whether exogenously administered testosterone alters muscle fiber morphology in skeletal muscle of young healthy, physically active women. Thirty-five young (20-35 years), recreationally trained women were randomly assigned to either 10-week testosterone administration (10 mg daily) or placebo. Before and after the intervention, hormone concentrations and body composition were assessed, and muscle biopsies were obtained from the vastus lateralis. Fiber type composition, fiber size, satellite cell- and myonuclei content, as well as muscle capillarization were assessed in a fiber type-specific manner using immunohistochemistry. Following the intervention, testosterone administration elevated serum testosterone concentration (5.1-fold increase, P=0.001), and induced significant accretion of total lean mass (+1.9%, P=0.002) and leg lean mass (+2.4%, P=0.001). On the muscle fiber level, testosterone increased mixed fiber cross-sectional area (+8.2%, P=0.001), an effect primarily driven by increases in type II fiber size (9.2%, P=0.006). Whereas myonuclei content remained unchanged, a numerical increase (+30.8%) was found for satellite cells associated with type II fibers in the Testosterone group. In parallel with fiber hypertrophy, testosterone significantly increased capillary contacts (+7.5%, P=0.015) and capillary-to-fiber ratio (+9.2%, P=0.001) in type II muscle fibers. The current study provides novel insight into fiber type-specific adaptations present already after 10 weeks of only moderately elevated testosterone levels in women.

Place, publisher, year, edition, pages
American Physiological Society, 2020
Keywords
androgens, capillarization, myonuclear domain, myonuclei, satellite cells
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-6096 (URN)10.1152/japplphysiol.00893.2019 (DOI)32191598 (PubMedID)
Available from: 2020-03-24 Created: 2020-03-24 Last updated: 2020-05-29Bibliographically approved
Eftestøl, E., Psilander, N., Cumming, K. T., Juvkam, I., Ekblom, M., Sunding, K., . . . Gundersen, K. (2020). Muscle memory: Are myonuclei ever lost? [Letter to the editor]. Journal of applied physiology, 128, 456-457
Open this publication in new window or tab >>Muscle memory: Are myonuclei ever lost?
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2020 (English)In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 128, p. 456-457Article in journal, Letter (Other academic) Published
Place, publisher, year, edition, pages
American Physiological Society, 2020
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5982 (URN)10.1152/japplphysiol.00761.2019 (DOI)31854249 (PubMedID)
Available from: 2020-01-07 Created: 2020-01-07 Last updated: 2020-02-24Bibliographically approved
Larsson, K., Kallings, L., Ekblom, Ö., Blom, V., Andersson, E. & Ekblom, M. (2019). Criterion validity and test-retest reliability of SED-GIH, a single item question for assessment of daily sitting time.. BMC Public Health, 19(1), Article ID 19:17.
Open this publication in new window or tab >>Criterion validity and test-retest reliability of SED-GIH, a single item question for assessment of daily sitting time.
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2019 (English)In: BMC Public Health, ISSN 1471-2458, E-ISSN 1471-2458, Vol. 19, no 1, article id 19:17Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Adults, Office-based work, Older adults, Reliability, Sedentary behaviour, Sitting, Validity, activPAL
National Category
Public Health, Global Health, Social Medicine and Epidemiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5520 (URN)10.1186/s12889-018-6329-1 (DOI)30611226 (PubMedID)
Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-01-08
Ekblom, M., Bojsen-Möller, E., Tarassova, O. & Ekblom, Ö. (2019). Day-to day variations in physical activity patterns affect corticospinal excitability on the following day. In: Brain Stimulation March-April 2019, vol 12, issue 2: . Paper presented at 3rd International Brain Stimulation Conference, Feb 24-27 2019, Vancouver (pp. 468). Elsevier, 12(2), Article ID 437.
Open this publication in new window or tab >>Day-to day variations in physical activity patterns affect corticospinal excitability on the following day
2019 (English)In: Brain Stimulation March-April 2019, vol 12, issue 2, Elsevier, 2019, Vol. 12, no 2, p. 468-, article id 437Conference paper, Oral presentation with published abstract (Other academic)
Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5738 (URN)10.1016/j.brs.2018.12.523 (DOI)
Conference
3rd International Brain Stimulation Conference, Feb 24-27 2019, Vancouver
Available from: 2019-05-09 Created: 2019-05-09 Last updated: 2019-12-02Bibliographically approved
Ekblom, M., Ekblom, Ö., Börjesson, M., Bergström, G., Jern, C. & Wallin, A. (2019). Device-Measured Sedentary Behavior, Physical Activity and Aerobic Fitness Are Independent Correlates of Cognitive Performance in Healthy Middle-Aged Adults-Results from the SCAPIS Pilot Study.. International Journal of Environmental Research and Public Health, 16(24), Article ID E5136.
Open this publication in new window or tab >>Device-Measured Sedentary Behavior, Physical Activity and Aerobic Fitness Are Independent Correlates of Cognitive Performance in Healthy Middle-Aged Adults-Results from the SCAPIS Pilot Study.
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2019 (English)In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, no 24, article id E5136Article in journal (Refereed) Published
Abstract [en]

High aerobic fitness, more moderate to vigorous physical activity (MVPA) and less sedentary behavior (SED) have all been suggested to promote cognitive functions, but it is unclear whether they are independent predictors of specific cognitive domains. This study aimed to investigate to what extent aerobic fitness MVPA and SED are independently associated with cognitive performance among middle-aged Swedish adults. We acquired device-based measures of aerobic fitness, cognitive performance and percent daily time spent in MVPA and SED in Swedish adults (n = 216; 54-66 years old). Aerobic fitness was associated with better performance at one out of two tests of speed/attention and one out of four tests of executive attention, and with worse performance at one of seven tests of memory. Increasing %MVPA was associated with better performance at one out of seven tests of memory and two out of three tests of verbal ability, whereas increasing %SED was associated with better performance at all four tests of executive attention and four out of seven tests of memory. These findings suggest that aerobic fitness, %MVPA and %SED are partly independent correlates of cognitive performance. To fully understand the association between SED and performance at several tests of cognitive function, future investigations might attempt to investigate intellectually engaging SED (such as reading books) separately from mentally undemanding SED (such as watching TV).

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
accelerometry, cognitive functions, exercise, physical activity, sedentary behavior
National Category
Public Health, Global Health, Social Medicine and Epidemiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5980 (URN)10.3390/ijerph16245136 (DOI)31888199 (PubMedID)
Available from: 2020-01-07 Created: 2020-01-07 Last updated: 2020-03-20
Gago, P., Arndt, A., Marques, M. C., Marinho, D. A. & Ekblom, M. (2019). Effects of post activation potentiation on electromechanical delay. Clinical Biomechanics, 70, 115-122
Open this publication in new window or tab >>Effects of post activation potentiation on electromechanical delay
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2019 (English)In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 70, p. 115-122Article in journal (Refereed) Published
Abstract [en]

Electromechanical delay (EMD) presumably depends upon both contractile and tensile factors. It has recently been used as an indirect measure of muscle tendon stiffness to study adaptations to stretching and training. The aim of the present study was to investigate whether contractile properties induced by a 6 s maximum voluntary isometric contraction (MVIC) could affect EMD without altering passive muscle tendon stiffness or stiffness index. Plantar flexor twitches were evoked via electrical stimulation of the tibial nerve in eight highly trained male sprinters before and after a 6 s MVIC in passive isometric or passively shortening or lengthening muscles. For each twitch, EMD, twitch contractile properties and SOLM-Wave were measured. Passive muscle tendon stiffness was measured from the slope of the relation between torque and ankle angle during controlled passive dorsal flexion and stiffness index by curve-fitting the torque angle data using a second-order polynomial function. EMD did not differ between isometric, lengthening or shortening movements. EMD was reduced by up to 11.56 ± 5.64% immediately after the MVIC and stayed depressed for up to 60 s after conditioning. Peak twitch torque and rate of torque development were potentiated by up to 119.41 ± 37.15% and 116.06 ± 37.39%, respectively. Rising time was reduced by up to 14.46 ± 7.22%. No significant changes occurred in passive muscle tendon stiffness or stiffness index. Using a conditioning MVIC, it was shown that there was an acute enhancement of contractile muscle properties as well as a significant reduction in EMD with no corresponding changes in stiffness. Therefore, caution should be taken when using and interpreting EMD as a proxy for muscle tendon stiffness.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Muscle, Twitch, Potentiation, Electromechanical delay, Stiffness
National Category
Physiology
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-5820 (URN)10.1016/j.clinbiomech.2019.08.001 (DOI)31476603 (PubMedID)
Note

At the time of Paulo Gago's dissertation this article was a manuscript.

Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2019-09-17Bibliographically approved
Organisations
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ORCID iD: ORCID iD iconorcid.org/0000-0002-7879-9188

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