| 1. |
- Ahokas, Essi K., et al.
(författare)
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Nocturnal Heart Rate Variability in Women Discordant for Hormonal Contraceptive Use
- 2023
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Ingår i: Medicine & Science in Sports & Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 55:7, s. 1342-1349
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The aim of this study was to investigate within-cycle differences in nocturnal heart rate (HR) and heart rate variability (HRV) in naturally menstruating women (NM) and women using combined hormonal contraceptives (CU) or progestin-only hormonal contraceptives (PU).Methods Physically active participants were recruited into three groups: NM (n = 19), CU (n = 11), and PU (n = 12). Participants’ HR and HRV (with Bodyguard 2 HRV monitor), and blood hormones were monitored during one menstrual cycle (MC) (NM-group) or for 4 weeks (CU and PU-groups). Estradiol, progesterone, and luteinizing hormone were analyzed from fasting blood samples collected four times in the NM (M1 = bleeding, M2 = follicular phase, M3 = ovulation, and M4 = luteal phase) and PU groups (M1 = lowest E2; M2 = M1 + 7 days; M3 = M1 + 14 days; M4 = M1 + 21 days) and twice in the CU group (active and inactive pill phases). After every blood sample, nightly HR and HRV were recorded and examined as an average from two nights.Results Hormonal concentrations differed (p < 0.05) between MC phases in the NM- and PU-groups, but not (p ≥ 0.116) between the active and inactive phases in the CU-group. In the NM- and PU-groups, some of the HRV values were higher, while in the NM-group, HR was lower during M2 compared to M3 (p < 0.049) and M4 (p < 0.035). In the CU-group, HRV values (p = 0.014-0.038) were higher, and HR was lower (p = 0.038) in the inactive phase compared to the first week of the active phase.Conclusions The MC and hormonal cycle phases influence autonomic nervous system balance, which is reflected in measurements of nocturnal HR and HRV. This should be considered when monitoring recovery in physically active individuals.
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| 2. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Effects of Aerodynamic Drag and Drafting on Propulsive Force and Oxygen Consumption in Double Poling Cross-Country Skiing
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 54:7, s. 1058-1065
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to investigate the effects of aerodynamic drag and drafting on propulsive force (FPROP), drag area (CDA), oxygen cost (V˙O2), metabolic rate (Ė), and heart rate (HR) during roller skiing on a treadmill in a wind tunnel using the double poling technique. A secondary aim was to investigate the effects of wind versus no-wind test conditions on the same physiological parameters. Methods Ten subjects of each gender participated in the experiments. One pair of skiers of the same gender roller skied simultaneously in line with the air flow; the distance between the skiers was 2.05 m. Each pair was tested as follows: I) with wind, leading; II) with wind, drafting; and III) without wind. The treadmill inclination was 0° throughout the tests. For the wind conditions, the air velocity was similar to the treadmill belt speed: 3 to 7 m·s-1 for men and 3 to 6 m·s-1 for women. Results Drafting resulted in significantly (P < 0.05) lower FPROP,CDA, V˙O2, and Ė, compared with leading, for both genders at racing speed but not at lower speeds, whereas HR was only affected for the male skiers at racing speed. The test without wind resulted in significantly lower FPROP, V˙O2, and Ė at all tested speeds compared with the tests with wind present, whereas HR was lower only at higher speeds. Conclusions At racing speed, but not at lower speeds, the positive effects of drafting behind a skier during double poling were obvious and resulted in a lower FPROP, CDA, V˙O2, Ė, and HR. Tests without wind present put even lower demands on the skiers' physiology, which was also evident at lower speeds.
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| 3. |
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| 4. |
- Emanuelsson, Eric B., et al.
(författare)
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MRI characterization of skeletal muscle size and fatty infiltration in long--term trained and untrained individuals
- 2022
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Ingår i: Physiological Reports. - : Wiley. - 2051-817X. ; 54:9, s. 389-389
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated body composition measures in highly trained and untrained individuals using whole--body magnetic resonance imaging (MRI). Additionally, correlations between these measures and skeletal muscle gene expression were performed. Thirty-six individuals were included: endurance-trained males (ME, n = 8) and females (FE, n = 7), strength-trained males (MS, n = 7), and untrained control males (MC, n = 8) and females (FC, n = 6). MRI scans were performed, and resting M. vastus lateralis (VL) biopsies were subjected to RNA sequencing. Liver fat fraction, visceral adipose tissue volume (VAT), total body fat, and total lean tissue were measured from MRI data. Additionally, cross-sectional area (CSA) and fat signal fraction (FSF) were calculated from Mm. pectoralis, M. erector spinae and M. multifidus combined, Mm. quadriceps, and Mm. triceps surae (TS). Liver fat fraction, VAT, and total body fat relative to body weight were lower in ME and FE compared with corresponding controls. MS had a larger CSA across all four muscle groups and lower FSF in all muscles apart from TS compared with MC. ME had a lower FSF across all muscle groups and a larger CSA in all muscles except TS than MC. FE athletes showed a higher CSA in Mm. pectoralis and Mm. quadriceps and a lower CSA in TS than FC with no CSA differences found in the back muscles investigated. Surprisingly, the only difference in FSF between FE and FC was found in Mm. pectoralis. Lastly, correlations between VL gene expression and VL CSA as well as FSF showed that genes positively correlated with CSA revealed an enrichment of the oxidative phosphorylation and thermogenesis pathways, while the genes positively correlated with FSF showed significant enrichment of the spliceosome pathway. Although limited differences were found with training in females, our study suggests that both regular endurance and resistance training are useful in maintaining muscle mass, reducing adipose tissue deposits, and reducing muscle fat content in males.
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| 5. |
- Irewall, Tommie, et al.
(författare)
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High Prevalence of Exercise-induced Laryngeal Obstruction in a Cohort of Elite Cross-country Skiers
- 2021
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Ingår i: Medicine & Science in Sports & Exercise. - : American College of Sports Medicine. - 0195-9131 .- 1530-0315. ; 53:6, s. 1134-1141
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Exercise-induced laryngeal obstruction (EILO) is a differential diagnosis for asthma and prevalent in athletes referred for exercise-induced dyspnoea. The aim of this study was to estimate the prevalence of EILO in elite cross-country skiers, known for a high prevalence of asthma.Method: Elite cross-country skiers were invited for screening of EILO. Screening consisted of clinical assessment, questionnaires, skin prick test, spirometry, eucapnic voluntary hyperventilation test, and continuous laryngoscopy during exercise test. Current asthma was defined as physician-diagnosed asthma and use of asthma medication during the last 12 months. EILO was defined as ≥2 points at the supraglottic or glottic level during exercise at maximal effort, using a visual grade score system.Result: A total of 89 (51% female) cross-country skiers completed the study. EILO was identified in 27% of the skiers, 83% of whom were female. All skiers with EILO had supraglottic EILO, there was no glottic EILO. Current asthma was present in 34 (38%) of the skiers, 10 (29%) of whom had concomitant EILO. In the skiers with EILO, a higher proportion reported wheeze or shortness of breath following exercise, compared to skiers without EILO. In skiers with EILO and current asthma, compared to skiers with asthma only, a higher proportion reported wheeze or shortness of breath following exercise. Asthma medication usage did not differ between these groups.Conclusion: EILO is common in elite cross-country skiers, especially females. Asthma and EILO may co-exist, and the prevalence of respiratory symptoms is higher in skiers with both. Testing for EILO should be considered in cross-country skiers with respiratory symptoms.
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| 6. |
- Jakobsson, Johan, et al.
(författare)
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Acute physiological effects of supramaximal high-intensity interval training in people with or without COPD
- 2023
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Ingår i: Medicine & Science in Sports & Exercise. - : Wolters Kluwer. - 0195-9131 .- 1530-0315. ; 55, s. 549-549
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Tidskriftsartikel (refereegranskat)abstract
- High-intensity exercise is essential for optimal development of cardiorespiratory fitness and health. This is, however, challenging for most people with chronic obstructive pulmonary disease (COPD) due to ventilatory limitations, leading to exercise at lower intensities accompanied by suboptimal stress on the cardiovascular and muscular system.PURPOSE: To compare the acute effects of a novel concept of short-duration supramaximal high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) in people with COPD and matched healthy controls (HC).METHODS: Sixteen people with mild to severe COPD (75 ± 6 yr; 8 males; 73 ± 13 FEV1%pred; 119 ± 37 W max aerobic power [MAP]) and 14 HC (74 ± 5 yr; 8 males; 106 ± 14 FEV1%pred; 169 ± 38 W MAP) performed HIIT and MICT on a cycle ergometer in a randomized order. HIIT consisted of 10x6s sprints interspersed with 1-min recovery and was performed at two intensities: 60% of max mean power output for 6-sec (MPO6) and 80%MPO6, estimated from the Borg cycle strength test. MICT consisted of 20-min at 60% of MAP, derived from a cardiopulmonary exercise test. Cardiorespiratory parameters, blood lactate concentration, ratings of exertion/symptoms, and exercise modality preference were obtained.RESULTS: Exercise characteristics and physiological data collected at the end of exercise are shown in Table 1. All HIIT sessions were completed, while 1 in 3 people with COPD did not complete MICT. The HIIT modality was preferred by 13/16 (COPD) and 12/14 (HC).CONCLUSION: Short-duration supramaximal HIIT was feasible and enabled a 3.5-fold increase in exercise intensity vs. MICT in people with COPD and HC. Notably, despite the higher exercise intensities, the cardiorespiratory demand during HIIT was similar to MICT and clinically relevant reductions in symptoms were seen in favor of HIIT, in people with COPD. Also, >80% of participants preferred HIIT over MICT.
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| 7. |
- Jones, Thomas W., et al.
(författare)
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Anthropometric, Physiological, and Performance Developments in Cross-country Skiers
- 2021
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Ingår i: Medicine & Science in Sports & Exercise. - : American collegeof sports medicine. - 0195-9131 .- 1530-0315. ; 53:12, s. 2553-2564
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to describe changes in laboratory-assessed anthropometric and physiological characteristics, training volumes, and competitive performance in national development-team cross-country skiers over a 25-month period, and to analyze whether changes in competitive performance could be predicted by changes in laboratory-assessed qualities and training volumes.Methods Data collected over 25 months from 30 national development-team cross-country skiers (14 women, 16 men; age, 18–23 yr) were analyzed retrospectively using multivariate statistics. Anthropometric and physiological characteristics were assessed via dual-energy x-ray absorptiometry and incremental roller-ski treadmill tests, respectively. Total training volumes and distributions of low- and high-intensity training were analyzed from online training diaries, and competitive performance was determined by International Ski Federation (FIS) distance and sprint points.Results Whole- and upper-body lean mass increased in the full cohort of skiers (n = 30; both P < 0.05), whereas lower-body lean mass, whole-body fat mass, speed and oxygen uptake (V˙O2) at a blood lactate concentration (BLa) of 2 and 4 mmol·L−1, as well as time-trial completion time, power output, and peak V˙O2, improved in the women only (all P < 0.05). Valid predictive models were identified for female skiers’ best FIS distance points (R2 = 0.81/Q2 = 0.51) and changes in FIS distance points (R2 = 0.83/Q2 = 0.54), with body mass, fat mass, lean mass, V˙O2peak, and speed at a BLa of 4 mmol·L−1 identified as consistently important variables for projection.Conclusions The valid prediction of competitive performance was achieved for women only in distance events. This study suggests that improvements in body composition and aerobic capacity may be more beneficial for elite female development-level skiers than for their male counterparts. These results have implications for athlete selection and performance development.
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| 8. |
- Kariippanon, Katharina E., et al.
(författare)
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Levels and Correlates of Objectively Measured Sedentary Behavior in Young Children : SUNRISE Study Results from 19 Countries
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - : Lippincott, Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 54:7, s. 1123-1130
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Tidskriftsartikel (refereegranskat)abstract
- Purpose There is a paucity of global data on sedentary behavior during early childhood. The purpose of this study was to examine how device-measured sedentary behavior in young children differed across geographically, economically, and sociodemographically diverse populations, in an international sample. Methods This multinational, cross-sectional study included data from 1071 children 3-5 yr old from 19 countries, collected between 2018 and 2020 (pre-COVID). Sedentary behavior was measured for three consecutive days using activPAL accelerometers. Sedentary time, sedentary fragmentation, and seated transport duration were calculated. Linear mixed models were used to examine the differences in sedentary behavior variables between sex, country-level income groups, urban/rural settings, and population density. Results Children spent 56% (7.4 h) of their waking time sedentary. The longest average bout duration was 81.1 +/- 45.4 min, and an average of 61.1 +/- 50.1 min center dot d(-1) was spent in seated transport. Children from upper-middle-income and high-income countries spent a greater proportion of the day sedentary, accrued more sedentary bouts, had shorter breaks between sedentary bouts, and spent significantly more time in seated transport, compared with children from low-income and lower-middle-income countries. Sex and urban/rural residential setting were not associated with any outcomes. Higher population density was associated with several higher sedentary behavior measures. Conclusions These data advance our understanding of young childrens sedentary behavior patterns globally. Country income levels and population density appear to be stronger drivers of the observed differences, than sex or rural/urban residential setting.
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| 9. |
- Leskinen, Tuija, et al.
(författare)
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The Effect of Consumer-based Activity Tracker Intervention on Physical Activity among Recent Retirees - An RCT Study
- 2021
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Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 53:8, s. 1756-1765
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The randomized controlled trial REACT (NCT03320746) examined the effect of a 12-month consumer-based activity tracker intervention on accelerometer-measured physical activity among recent retirees. Methods Altogether 231 recently retired Finnish adults (age, 65.2 ± 1.1 yr, mean ± SD; 83% women) were randomized to intervention and control groups. Intervention participants were requested to wear a commercial wrist-worn activity tracker (Polar Loop 2; Polar, Kempele, Finland) for 12 months, to try to reach the daily activity goals shown on the tracker display, and to upload their activity data to a Web-based program every week. The control group received no intervention. Accelerometer-based outcome measurements of daily total, light physical activity (LPA), and moderate to vigorous (MVPA) physical activity were conducted at baseline and at 3-, 6-, and 12-month time points. Hierarchical linear mixed models were used to examine the differences between the groups over time. All analyses were performed by intention-to-treat principle and adjusted for wake wear time. Results The use of a commercial activity tracker did not increase daily total activity, LPA, or MVPA over the 12-months period when compared with nonuser controls (group-time interaction, P = 0.39, 0.23, and 0.77, respectively). There was an increase in LPA over the first 6 months in both the intervention (26 min·d-1, 95% confidence interval [CI] = 13 to 39) and the control (14 min·d-1, 95% CI = 1 to 27) groups, but the difference between the groups was not significant (12 min·d-1, 95% CI = -6 to 30). In both groups, LPA decreased from 6 to 12 months. Conclusion The 12-month use of a commercial activity tracker does not appear to elicit significant changes in the daily total activity among a general population sample of recent retirees, thus highlighting the need to explore other alternatives to increase physical activity in this target group. © Lippincott Williams & Wilkins.
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| 10. |
- Mawhinney, Chris, et al.
(författare)
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Cool-Water Immersion Reduces Postexercise Quadriceps Femoris Muscle Perfusion More Than Cold-Water Immersion
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - Philadelphia, PA : Lippincott Williams & Wilkins. - 0195-9131 .- 1530-0315. ; 54:7, s. 1085-1094
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The muscle perfusion response to postexercise cold-water immersion (CWI) is not well understood. We examined the effects of graded postexercise CWI upon global and regional quadriceps femoris muscle perfusion using positron emission tomography and [15O]H2O. Methods: Using a matched-group design, 30 healthy men performed cycle ergometer exercise at 70% VO2peak to a core body temperature of 38°C, followed by either 10 min of CWI at 8°C, 22°C, or seated rest (control). Quadriceps muscle perfusion; thigh and calf cutaneous vascular conductance; intestinal, muscle, and local skin temperatures; thermal comfort; mean arterial pressure; and heart rate were assessed at preexercise, postexercise, and after CWI. Results: Global quadriceps perfusion was reduced beyond the predefined minimal clinically relevant threshold (0.75 mL per 100 g·min-1) in 22°C water versus control (difference (95% confidence interval (CI)), -2.5 (-3.9 to -1.1) mL per 100 g·min-1). Clinically relevant decreases in muscle perfusion were observed in the rectus femoris (-2.0 (-3.0 to -1.0) mL per 100 g·min-1) and vastus lateralis (-3.5 (-4.9 to -2.0) mL per 100 g·min-1) in 8°C water, and in the vastus lateralis (-3.3 (-4.8 to -1.9) mL per 100 g·min-1) in 22°C water versus control. The mean effects for vastus intermedius and vastus medialis perfusion were not clinically relevant. Clinically relevant decreases in thigh and calf cutaneous vascular conductance were observed in both cooling conditions. Conclusions: The present findings revealed that less noxious CWI (22°C) promoted clinically relevant postexercise decreases in global quadriceps muscle perfusion, whereas noxious cooling (8°C) elicited no effect. © Lippincott Williams & Wilkins
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