Medicine and Science in Sports and Exercise最新文献

{"title":"Blood Flow Restriction Accelerates the Onset of Neuromuscular Fatigue, Anaerobic Metabolism, and Maximal Oxygen Uptake.","authors":"Sean M Lubiak, Mason A Howard, Jeffrey T Schmidt, David H Fukuda, Jeffrey R Stout, Joshua L Keller, Ethan C Hill","doi":"10.1249/MSS.0000000000004189","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004189","url":null,"abstract":"<p><strong>Purpose: </strong>Prescribing aerobic exercise with blood flow restriction (BFR) relative to physical working capacity at the fatigue threshold (PWCFT), gas exchange threshold (GET), respiratory compensation point (RCP), or maximal oxygen uptake (V̇O2max) derived from an incremental exercise test without BFR may inaccurately estimate exercise intensity. The purpose of this investigation was to examine the acute effects of an incremental cycling test performed with and without BFR on PWCFT, GET, RCP, and V̇O2max.</p><p><strong>Methods: </strong>Eighteen aerobically trained females completed an incremental cycling test and a verification bout with and without BFR on separate visits. Each test began with a five-minute warmup at 50 watts (W) and a cadence of 70 revolutions per minute. Following this, the test began at 50 W and increased by 30 W every two minutes until volitional failure. To apply BFR during the incremental protocol, pneumatic cuffs were placed bilaterally to the upper thighs after the warmup. Separate Bayesian paired samples t-tests were performed and are reported as a meaningful difference if the 95% high-density interval (95% HDI) did not include zero.</p><p><strong>Results: </strong>Applying BFR decreased PWCFT (95% HDI: 28.0 to 46.4 W), decreased V̇O2 at GET (95% HDI: 104.0 to 307.0 mL˙min -1), decreased V̇CO2 at GET (95% HDI: 115.0 to 347.0 mL˙min -1), decreased V̇O2 at RCP (95% HDI: 257.0 to 403.0 mL˙min -1), decreased V̇CO2 at RCP (95% HDI: 329.0 to 525.0 mL˙min -1), and decreased V̇O2max (95% HDI: 374.0 to 470.0 mL˙min -1) relative to the unrestricted incremental cycling test.</p><p><strong>Conclusions: </strong>These responses suggest that BFR accelerated the recruitment of higher threshold motor units, induced earlier shifts to the heavy and severe exercise domains, and expedited the plateau in maximal oxygen uptake.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149167482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"eHealth-Guided Exercise Improves Peak Oxygen Uptake and Health-Related Quality of Life After COVID-19: A Randomized Controlled Trial.","authors":"Espen Alexander Eriksen, Ulrik Wisløff, Ottar Brohaug Welde, Sindre Midttun, Eli Anne Skaug, Jon Magne Letnes, Ross Arena, Patrick Dunn, Tommi Vasankari, Torbjørn Omland, Dorthe Stensvold","doi":"10.1249/MSS.0000000000004177","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004177","url":null,"abstract":"<p><strong>Purpose: </strong>Physical activity (PA) levels declined during the COVID-19 pandemic, contributing to reduced fitness and quality of life. eHealth tools may help increase PA. In a six-month randomized controlled trial, we evaluated Activity Quotient (AQ), an innovative eHealth tool designed to promote PA and improve peak oxygen uptake (V̇O2peak), compared with standard advice on national PA recommendations in physically inactive adults recovering from COVID-19.</p><p><strong>Methods: </strong>Seventy-seven participants with previous COVID-19 infection were randomized 1:1 to either receive: 1) an eHealth-guided exercise intervention (n=38), using AQ to motivate for a PA dose that led to >100 weekly AQs, or 2) a control group (n=39) advised to follow standard PA recommendations. V̇O2peak scaled for fat-free mass (FFM) was the primary outcome, assessed in a subsample of participants who completed clinical assessment (n=33; eHealth group n=16, control n=17), while secondary outcomes included physical and mental scores of health-related quality of life (HRQoL). Linear mixed-effects models were used to analyze the effects of the intervention.</p><p><strong>Results: </strong>Participants (79% women) were 41.4±10.0 years and had a BMI of 28.8±5.9 kg/m². Among 33 participants who completed clinical assessment, V̇O2peak increased 4.9 mL•kgFFM -1•min -1 (95%CI 1.2 to 8.7, p=0.0134) more in the eHealth group compared with controls. Mental HRQoL increased by 9.8 points (95% CI 2.5 to 17.0, p=0.009) more in the eHealth group compared with controls. No between-group difference was observed in physical score of HRQoL.</p><p><strong>Conclusions: </strong>A six-month eHealth-guided exercise intervention using AQ was more effective than standard PA advice in improving V̇O2peak and mental HRQoL among physically inactive adults recovering from COVID-19. These findings highlight the potential of AQ as an effective and feasible approach for post-COVID rehabilitation.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149137338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Validation of a Resting Metabolic Rate Equation for Elite Cyclists.","authors":"Maartje Cox, Zoi Balamouti, Job van Leeuwen, Boy Sanders, Dajo Sanders, Gerard Rietjens, Guy Plasqui, Bas Van Hooren","doi":"10.1249/MSS.0000000000004181","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004181","url":null,"abstract":"<p><strong>Purpose: </strong>Accurate determination of energy expenditure (EE) in elite endurance athletes is critical for personalised nutrition strategies aimed at maintaining health and optimising performance. The resting metabolic rate (RMR) constitutes a large portion of daily EE, but existing RMR predictive equations are not suitable for this population due to differences in body composition and energy intake and expenditure between the general population and elite endurance athletes.</p><p><strong>Methods: </strong>The RMR of 48 male and 30 female elite cyclists (UCI ProTeam or WorldTour level) was measured with indirect calorimetry using a ventilated hood system. A new RMR predictive equation was developed using height, mass, and sex as predictors. Stepwise forward regression was used to select the independent variables to be included in the equation. The strength of the association between individual predictors and RMR was quantified through partial correlations. The new equation was validated with a leave-one-out cross-validation (LOOCV). Correlations between RMR estimated with existing equations and measured RMR were evaluated.</p><p><strong>Results: </strong>The final equation was RMR (kcal/day) = -288.98 + 5.77×height (cm) + 14.25×mass (kg) + 180.79×sex (male=1). Partial correlations of height, mass, and sex were 0.19, 0.41, and 0.42, respectively. Root mean squared error of the LOOCV was 134.78 kcal/day. The LOOCV model showed comparable absolute agreement between the newly developed equation and measured RMR (overestimation of 0.65 kcal/day) as the Ten Haaf equation (underestimation of 10.24 kcal/day), which both performed better than other existing equations (underestimations of 149.17-212.85 kcal/day.</p><p><strong>Conclusions: </strong>This study provides RMR data for the largest cohort of elite cyclists to date. The newly developed RMR formula provides specificity to elite cyclists and can be readily applied to endurance athletes of similar age, body composition, and with similar energy intake and expenditure.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149137272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the FIT FIRST Teen Multisport Program on Adolescents' Physical Fitness and Well-Being: A Cluster Randomized Controlled Trial.","authors":"Giampiero Tarantino, Nikos Ntoumanis, Sofie Koch, Malte Nejst Larsen, Christina Birch Meiner, Chiara Cimenti, Magnus Gjesing Christensen, Peter Krustrup, Cecilie Thøgersen-Ntoumani","doi":"10.1249/MSS.0000000000004161","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004161","url":null,"abstract":"<p><strong>Purpose: </strong>School-based physical education (PE) can counter declines in fitness in adolescence, yet scalable, curriculum-embedded fitness programmes are scarce. We evaluated the implementation of FIT FIRST Teen (FFT), a teacher-delivered, high-intensity multisport programme across one school year.</p><p><strong>Methods: </strong>A cluster randomised controlled trial was conducted in 22 Danish schools (FFT, n=517; Control, n=860). Teachers in FFT were trained via a 1-day course and a manual and delivered three 40-minute lessons/week. The primary outcome was cardiorespiratory fitness, assessed via the Yo-Yo Intermittent Recovery Level 1 Children's test (YYIR1C). Secondary outcomes included handgrip strength, agility, balance, body composition, resting heart rate, and well-being. Multilevel modelling assessed the effectiveness of FFT, and exploratory latent transition analysis (LTA) was used to uncover latent fitness profiles and transitions over time in the two arms.</p><p><strong>Results: </strong>Compared with controls, adolescents allocated to FFT showed greater improvements in cardiorespiratory fitness, with a mean pre-post difference in YYIR1C distance of 106 m (p=0·009). In terms of secondary outcomes FFT showed greater gains in handgrip strength (~0.81 kg; p=0·012), and muscle mass (~0·44 kg; p<0.001). No intervention effects were observed in terms of well-being. Exploratory LTA supported a four-profile solution (high-fit, moderately-high-fit, moderately-low-fit, low-fit) and suggested that adolescents in the FFT group were more likely to remain in high-fit profile membership over time, compared to the control arm participants who tended to transition towards worse fitness profiles.</p><p><strong>Conclusions: </strong>Compared to the control arm, a 40-wk intervention with FFT improved cardiovascular fitness, handgrip strength, and muscle mass. FFT offers an alternative to PE curricula to improve adolescents' physical fitness.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Greater Ankle Laxity and Smaller Evertor Muscles in Conjunction are Linked to Symptoms of Chronic Ankle Instability in Collegiate Basketball Athletes.","authors":"Naoaki Ito, Matthew B Blomquist, Claire S Tanaka, Jack A Martin, Kelly Bachus, Brent Neuharth, James A Snider, A J Whitehead, Katharine Carter, Bryan C Heiderscheit","doi":"10.1249/MSS.0000000000004157","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004157","url":null,"abstract":"<p><strong>Purpose: </strong>Investigate the combined effects of ankle joint laxity and evertor muscle size on symptoms of chronic ankle instability (CAI) using both quantitative imaging and clinical gradings of laxity. We also aimed to establish the relationship between quantitative and clinical measures of laxity.</p><p><strong>Methods: </strong>Division-I basketball athletes underwent preseason magnetic resonance imaging to quantify evertor muscle volumes and completed the Cumberland Ankle Instability Tool (CAIT). Laxity, defined as maximum talofibular displacement, was measured during a reverse anterolateral drawer test (RALD) using Bmode ultrasound and an opticalflow bonetracking algorithm. Clinical RALD gradings (positive/negative) were assigned by the physical therapist performing the test. Linear mixedeffects models evaluated (1) the effects of displacement, evertor muscle volume, and their interaction on CAIT scores, adjusting for sex, and (2) the association between clinical RALD grade and maximum displacement.</p><p><strong>Results: </strong>Twentynine athletes (58 ankles) were included for the quantitative versus clinical laxity comparison; 21 athletes (36 ankles) were included for the primary analysis. Maximum displacement differed between clinical RALD grades (p < 0.01), with greater displacement in positive versus negative tests. There was a significant interaction effect between displacement and evertor muscle volume on CAIT scores (p < 0.01). Greater laxity related to worse CAIT scores, particularly in athletes with smaller evertor muscle volumes. The model using clinical RALD grade did not show significant effects on CAIT scores.</p><p><strong>Conclusions: </strong>Greater ultrasoundquantified ankle laxity was associated with more severe CAI symptoms; however, this relationship was weaker in athletes with larger evertor muscles. Ultrasoundbased measures of laxity were associated with CAI, whereas clinical gradings were not, indicating that quantitative measures of laxity may serve as a valuable metric for future research and guiding clinical care.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Negative Static Lung Load and Immersion Pulmonary Edema in Healthy Divers: The Determinant Role of Breathing-Gas Source Position.","authors":"Thibaut Prevautel, Olivier Castagna, Emmanuel Gempp, Jean-Eric Blatteau, Raphael Demoulin, Pierre Louge","doi":"10.1249/MSS.0000000000004159","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004159","url":null,"abstract":"<p><strong>Purpose: </strong>Immersion pulmonary edema (IPE) affects divers and swimmers across the age and fitness spectrum, including young, trained individuals, indicating that mechanical factors act alongside any cardiovascular predisposition. We hypothesized that an extreme negative static lung load (SLL), produced when the breathing-gas source sits shallower than the pulmonary centroid during prone swimming, increases extravascular lung water as a function of gas-source position rather than device type.</p><p><strong>Methods: </strong>This translational study combined a retrospective analysis of 21 rebreather-associated IPE cases in healthy professional divers (2009-2015) and a prospective cross-over study in 15 healthy volunteers who performed a standardized 30-minute prone finning exercise in cold water twice: with an open-circuit system (near-neutral SLL) and a back-mounted rebreather (negative SLL). Extravascular lung water was quantified by ultrasound lung comets (ULC); inspiratory work of breathing (WOB) and mean hydrostatic load were measured in immersion with a pneumo-baro-tachograph across body positions.</p><p><strong>Results: </strong>All 21 cases (median age 32) occurred in divers free of cardiovascular disease with a back-mounted gas source generating negative SLL; 34% developed without exertion, and depth was not distinguishing (median 21 m, range 7-80). The prone position imposed a mean hydrostatic load near -32 cmH2O and an inspiratory WOB of approximately 3.3 J/L, versus 1.3-1.5 J/L when vertical. After diving, increased extravascular lung water (ULC > 5) was more prevalent with negative SLL than open-circuit (80% vs 27%; McNemar P =.008), despite a greater distance covered with open-circuit.</p><p><strong>Conclusions: </strong>An extreme negative SLL set by gas-source position is associated with markedly increased inspiratory loading and extravascular lung water, independent of exertion. These findings support continued consideration of SLL in the physiological evaluation and safety assessment of occupational life-support systems.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inter-Muscle, -Limb, and -Day, Effects on Motor Unit Discharge Rates of the Superficial Quadriceps Femoris Muscles.","authors":"Alexander D Paish, Brian H Dalton, Neil D Eves, Charles L Rice, Chris J McNeil","doi":"10.1249/MSS.0000000000004160","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004160","url":null,"abstract":"<p><p>Despite the quadriceps being a large muscle group with distinct heads, no study has compared motor unit discharge rates (MUDRs) of the three superficial portions in the same participants. Further, day-to-day variability of quadriceps MUDRs and the influence of limb dominance have not been evaluated. Thus, during submaximal contractions, we assessed MUDRs of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) of the dominant and non-dominant limbs on two separate days. We hypothesized that MUDRs of the RF would be faster than VM and VL but not different between the VM and VL. Additionally, MUDRs would not be different between limbs, or days. During two identical sessions (≥72h apart), 16 healthy, young adults (8 females, 27±7y) performed repeated (7-14 per limb) 15-s isometric contractions at 25% of maximal knee extensor force. Motor unit trains (≥24 per muscle) were recorded from concentric needle electrodes inserted separately into the VL, RF, and VM, and analyzed using decomposition-based quantitative electromyography software. Muscle order was pseudorandomized, though consistent for each limb within a participant. A total of 5391 motor unit trains were included for analysis (26.9±5.5 per muscle per participant). Independent of limb dominance and day (main effects and interactions all P≥0.115), the mean MUDR for RF (12.6±1.8Hz) was faster than VL (10.2±1.5Hz) and VM (10.9±1.7Hz), and VM was faster than VL (all P≤0.001). The results indicate the three superficial quadriceps muscles have unique motor unit rate modulation, possibly reflecting different relative contributions to knee extension force production.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Higher Workload, not Hypoxia, Enhances Acute Mitochondrial Respiratory Responses to High-Intensity Interval Exercise in Men with Overweight or Obesity.","authors":"Zhenhuan Wang, David J Bishop, Muhammed M Atakan, Jujiao Kuang, Andrew Garnham, Michael J McKenna, Jia Li, Li Peng, Olivier Girard, Xu Yan","doi":"10.1249/MSS.0000000000004158","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004158","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Purpose: &lt;/strong&gt;This study investigated whether skeletal muscle mitochondrial responses to a single session of high-intensity interval exercise (HIIE) in men with overweight or obesity were influenced by hypoxia or absolute power output. The HIIE performed in hypoxia (HY; inspired oxygen fraction [FiO2] = 14.0%) was matched with HIIE performed in normoxia (FiO₂ = 20.9%) for either absolute power output (NA) or relative intensity (NR). Our primary hypothesis was that both HY and NR would elicit greater acute increases in skeletal muscle mitochondrial respiratory capacity than NA. Our secondary hypothesis was that HY and NR would produce comparable skeletal muscle oxygen desaturation and responses in mitochondrial-related gene expression and protein content.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Twelve men with overweight or obesity (mean±standard deviation [SD]: age, 32.3±7.3 years; body mass index [BMI], 29.0±1.9 kg·m⁻²) completed HIIE under three experimental conditions (HY, NR, and NA) in a randomized crossover design, with each trial separated by a one-week washout period. Exercise intensities were prescribed using lactate threshold (LT) and peak power output (PPO) obtained during graded exercise tests (GXT). HY and NA were matched for absolute power output (185±57 W) using the LT and PPO obtained from the hypoxic GXTs. NR was matched to HY for relative intensity using the LT and PPO obtained from the normoxic GXTs, resulting in a higher power output (210±65 W) than in HY and NA. Each HIIE consisted of six 4-min cycling intervals interspersed with 2-min recovery periods. Venous blood samples and vastus lateralis muscle biopsies were obtained at baseline and 0, 3, and 24 h post-exercise.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Arterial oxygen saturation and muscle tissue saturation index were lower during HY compared with NA (p&lt;0.05). Twenty-four hours after HIIE, electron transfer flavoprotein- and complex I+II-linked oxidative phosphorylation and electron transport system capacities [(ETF+CI+II)P and (ETF+CI+II)E] were greater following NR than NA (p&lt;0.05). Mitochondrial DNA copy number and citrate synthase activity were unchanged. PGC-1α and PGC-1α4 mRNA expression levels significantly increased 3 h after HIIE relative to baseline in all conditions (p&lt;0.05), with no significant differences between conditions (p&gt;0.05). HIF-1α and VEGF mRNA increased following NR and HY, respectively (p&lt;0.05). Protein expression of PGC-1α and phosphorylated p38 increased immediately after NA and NR, while phosphorylated mTOR increased after NR (p&lt;0.05). HIF-1α protein increased 3 and 24 h post-HIIE in NR (p&lt;0.05).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Despite greater systemic and muscle oxygen desaturation, hypoxic HIIE did not enhance mitochondrial respiratory capacity or markers of mitochondrial content and biogenesis. Conversely, mitochondrial respiration increased following normoxic HIIE performed at a higher power output, suggesting that exercise workload, r","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Timing of Device-Measured Physical Activity and Sleep in Relation to Meeting Physical Activity Guidelines in U.S. Adults.","authors":"Kai Zhang, Justin J Lang, Sitong Chen, Rachel C Colley, Pedro F Saint-Maurice, Alex Dumas, Grant R Tomkinson, Jean-Philippe Chaput","doi":"10.1249/MSS.0000000000004154","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004154","url":null,"abstract":"<p><strong>Introduction: </strong>Whether the timing of moderate-to-vigorous physical activity (MVPA) and sleep is independently and jointly associated with meeting physical activity guidelines in adults remains unclear.</p><p><strong>Methods: </strong>We cross-sectionally analyzed 2003-2006 National Health and Nutrition Examination Survey (NHANES) data. Non-pregnant adults aged ≥20 years with valid accelerometer data, ≥5 min/day of MVPA, and no mobility limitation were included (n=3,153). Participants were classified as: morning (06:00-09:59), midday (10:00-13:59), afternoon (14:00-17:59), evening (18:00-21:59), or overnight (22:00-05:59) MVPA groups if ≥50% of average daily MVPA occurred in that window; or as mixed if otherwise. Subsamples with valid sleep timing proxy data (n=2,370) were classified as: irregular sleepers if participants had a standard deviation of the sleep midpoint >1 h; otherwise, regular sleepers were further categorized by mean sleep midpoint as early (22:00-01:59), mid (02:00-03:59), or late (04:00-07:59). Survey-weighted modified Poisson models were used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) for meeting PA guidelines (i.e., ≥150 min/week of moderate-equivalent activity), controlling for sociodemographic, behavioral, and health-related covariates.</p><p><strong>Results: </strong>Morning MVPA (PR = 1.48, 95% CI = 1.31-1.66) and early sleep (1.14, 1.01-1.28) were each associated with a higher prevalence of meeting PA guidelines compared to mixed MVPA and irregular sleep, respectively. Similar patterns were observed for joint groups of morning MVPA with early sleep (1.57, 1.14-2.16), morning MVPA with mid sleep (1.62, 1.34-1.96), and midday MVPA with mid sleep (1.44, 1.21-1.73) compared with mixed MVPA with irregular sleep.</p><p><strong>Conclusions: </strong>Accumulating MVPA predominantly in the morning and/or maintaining earlier sleep timing may inform timing-based strategies to support population-level adherence to PA guidelines.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149075251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat Stress and Elite Tennis Performance: A 26-Year Analysis of Grand Slam Match Dynamics in a Warming Climate.","authors":"Liam Simani, Yoram Epstein, Itay Ketko","doi":"10.1249/MSS.0000000000004152","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004152","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate the association of elevated ambient heat stress with elite men's tennis performance, match dynamics and competitive outcomes.</p><p><strong>Methods: </strong>This retrospective cohort study analyzed 13,081 men's matches in all four Grand Slam tournaments from 2000-2025, linked with localized meteorological data. Tournaments were classified as \"Hot\" if the mean Heat Index exceeded the local 26-year average by ≥1.0 standard deviation; remaining tournaments were classified as \"Control\". Categorical and continuous outcomes included measures of match completion, technical performance, competitive outcomes, and temporal match characteristics.</p><p><strong>Results: </strong>\"Hot\" tournaments clustered heavily in the last decade. Elevated thermal stress inverted the winner-minus-loser age gap from -0.21 to +0.16 years (p<0.01), indicating a relative advantage for older athletes. Match pace differed between environmental conditions: median match pace was 1.47 points per minute during Hot tournaments vs. 1.53 points per minute during Control tournaments (p<0.001), and median match duration was 149 min. vs. 141 min. (p<0.001). Technical metrics showed subtle alterations, including higher double-fault rates (3.71% vs. 3.50%, p<0.001). While overall match non-completion rates and ranking upsets remained stable globally, the non-completion rate nearly doubled at the US Open (8.35% vs. 4.65%, p<0.001).</p><p><strong>Conclusions: </strong>Elevated Heat Index was associated with small but consistent changes in elite men's tennis match dynamics. The observed reduction in match pace is consistent with self-pacing under elevated thermal stress. These findings carry vital implications for sports sectors where the capacity to regulate effort intensity is constrained. Sporting organizations should consider proactive heat-management frameworks, including environmental monitoring, scheduling, acclimatization, and cooling interventions, to safeguard athletes' health and preserve performance.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149039727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}