Medicine and Science in Sports and Exercise最新文献

{"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}

{"title":"High-Protein Meal Replacement Intervention in Overweight and Obese Career Firefighters: A Cluster Randomized Controlled Trial.","authors":"Amber N Schmitz, Andrew J Tweedell, Craig R Kleinberg, Gena R Gerstner, Nicholas A Buoncristiani, Eric D Ryan","doi":"10.1249/MSS.0000000000004151","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004151","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this cluster randomized controlled trial was to examine the effectiveness of a 14-week high-protein meal replacement (MRP) intervention on macronutrient intake, body composition, cardiometabolic health, and stair climb (SC) performance in career firefighters with overweight and obesity, and collect acceptability data to inform implementation efforts.</p><p><strong>Methods: </strong>Twenty-six fire stations (51 firefighters; 36.7±7.3yrs; 33.1±4.8kg·m -2) were randomized to a MRP or wait-list control (CON) group. The MRP group consumed one shake/day (week 1) and two shakes/day (weeks 2-14) ad libitum. The primary outcome was percent body fat (%BF) measured by dual-energy x-ray absorptiometry, and secondary outcomes included macronutrient intake, body mass (BM), body mass index (BMI), regional fat distribution, resting heart rate (RHR) and blood pressure (BP), blood lipids, a weighted and timed SC task, and HR recovery (HRrec) following the SC task. Intervention acceptability was assessed in the MRP group. Linear mixed models assessed intervention effects with an alpha level set at 0.05.</p><p><strong>Results: </strong>The MRP group improved %BF (-1.0 [-1.9, -0.06]; P=0.038) and secondary outcomes including dietary intake [increase in protein and fiber intake (P≤0.044); decrease in the CHO:PRO ratio (P=0.008)], body composition [BM, BMI, trunk fat mass (FM), and android:gynoid and trunk:limb %BF ratios (P≤0.026)], and SC HRrec (P<0.001). The MRP intervention had no significant effects on total calories, fat intake, lean mass, limb FM, RHR and BP, blood lipids, or SC time (P=0.135-0.985). Shake adherence was high (90.7±11.8%) and firefighters reported the intervention was convenient and they would continue long-term.</p><p><strong>Conclusions: </strong>The MRP intervention improved macronutrient intake, body composition, and SC HRrec and was well accepted, supporting a practical nutritional strategy to improve health in firefighters with overweight and obesity.</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":"149039673","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":"The Impact of Air Temperature, Relative Humidity, and Solar Irradiance on Ultramarathon Running Speed in Women and Men.","authors":"Michal Struška, Martin Hora, Cara Wall-Scheffler, Vladimír Sládek","doi":"10.1249/MSS.0000000000004148","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004148","url":null,"abstract":"<p><strong>Introduction/purpose: </strong>The running speed of women was suggested to be less impacted by heat stress than that of men in marathons, but this has been scarcely studied in ultramarathons. Lower running speeds in ultramarathons may reduce heat stress and therefore attenuate weather-related sex differences compared with marathons. We examined how air temperature, relative humidity, and solar irradiance influence running speed and the relative difference in speed between sexes during 50-161-km ultramarathons.</p><p><strong>Methods: </strong>We analyzed 1,353,878 finish times in 8,582 races held at daily-averaged air temperatures of 0-34 °C, relative humidity of 0-100%, and solar irradiance levels of 0-700 W/m 2. Using a linear mixed-effects model, we estimated running speed in women and men, and the difference in speed between sexes across weather conditions.</p><p><strong>Results: </strong>Running speed declined in both sexes at high air temperatures, with the decline steeper in men, reducing the difference between sexes from 0.73 km/h at 0-8 °C to 0.34 km/h at 34 °C. The negative effect of high air temperature on the sex difference was most pronounced at high relative humidity, with the predicted difference declining to 0.21 km/h at 34 °C and 90% RH. Relative humidity had the opposite, but weaker, effect, increasing the sex difference by 0.07 km/h across its observed range. Solar irradiance had a small effect on running speed, and the effect did not differ significantly between men and women.</p><p><strong>Conclusions: </strong>In ultramarathons, women's running speed is less affected by high air temperature than men's running speed. This effect is most pronounced at high relative humidity.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983033","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":"A Novel Preclinical Mouse Model of Voluntary Active Stretching Suppresses Mammary Tumor Progression.","authors":"Yi He, Lisbeth Berrueta, Yan Wang, Gary J Badger, Helene M Langevin","doi":"10.1249/MSS.0000000000004150","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004150","url":null,"abstract":"<p><strong>Purpose: </strong>Although exercise is recommended after a breast cancer diagnosis, most survivors remain physically inactive due to cancer-related physical limitations. Identifying a gentle yet effective exercise modality is a critical but underexplored need in cancer care. This preclinical study aims to address this gap by developing a mouse model of voluntary active stretching to investigate the direct effects of gentle active stretching on mammary tumor growth and metastasis.</p><p><strong>Methods: </strong>Female FVB mice were used with a video-based customizable home-cage behavior tracking system for behavior modeling. Height-elevated food, water, and enrichment within the home cage were used to promote self-stretching in mice. Subsequently, this model was used to compare the effects of voluntary active stretching and voluntary running on tumor growth and lung metastasis in the MET-1 and 6DT1 orthotopic mammary tumor FVB mouse models. Proteomics analysis of tumor tissue was performed for mechanistic investigation.</p><p><strong>Results: </strong>The custom cage setting effectively elicited mouse voluntarily active stretching in long-term observation. Both voluntary active stretching and voluntary running significantly suppressed tumor growth in the MET-1 orthotopic mammary tumor model, despite voluntary active stretching being a lower-intensity exercise modality. In a more metastatic 6DT1 orthotopic model, voluntary active stretching reduced primary tumor growth and the incidence of larger lung metastases, whereas voluntary running produced no effect. Proteomics analyses further suggested that voluntary active stretching may induce more favorable molecular changes in primary tumors than voluntary running.</p><p><strong>Conclusions: </strong>This study establishes a novel preclinical voluntary active stretching model and uncovers an underrecognized therapeutic potential of self-stretching to mitigate mouse mammary cancer progression. These findings provide preclinical evidence that voluntary active stretching has beneficial effects on tumor growth and metastasis in mice and warrants further mechanistic and clinical investigation. This study can serve as a translational bridge for developing gentle human stretching and yoga-based interventions for patients with breast cancer.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983012","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":"Does Training Status Influence Myokine Levels and Cancer Cell Survival In Vitro? Effects of a Single Bout of Exercise in Breast Cancer Survivors.","authors":"Francesco Bettariga, Dennis R Taaffe, Cristina Crespo-Garcia, Anna Maria Markarian, Timothy D Clay, John P Campbell, Sanjeev Adhikari, Elin S Gray, Nicolas H Hart, Daniel A Galvão, Robert U Newton","doi":"10.1249/MSS.0000000000004149","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004149","url":null,"abstract":"<p><strong>Purpose: </strong>We investigated the impact of training status (untrained versus trained) on acute myokines with anti-cancer properties and cancer cell suppression before (untrained) and after (trained) a 12-week resistance training (RT) vs high-intensity interval training (HIIT) program.</p><p><strong>Methods: </strong>Twenty-eight breast cancer survivors completed a single bout (defined as one complete exercise session) of RT or HIIT before and after a 12-week structured RT or HIIT program. Blood was collected before, immediately and 30 minutes after each acute RT or HIIT session to measure serum levels of myokines (decorin, interleukin 6 [IL-6], secreted protein acidic and rich in cysteine [SPARC], and oncostatin M [OSM]) and MDA-MB-231 cell growth in vitro.</p><p><strong>Results: </strong>The acute session after a 12-week RT or HIIT significantly increased myokine levels compared to the acute session pre-training (p < 0.05), with elevations observed for IL-6 and OSM in RT (generalized eta squared [ges] = 0.029 to 0.131) and decorin and OSM in HIIT (ges = 0.016 to 0.031). The acute exercise session performed after 12 weeks of RT or HIIT induced significantly greater cancer-suppressive effects on MDA-MB-231 cells in vitro compared to the pre-training session (p < 0.05), with inhibitory effects observed in RT (ges = 0.156) and HIIT (ges = 0.052).</p><p><strong>Conclusions: </strong>A single exercise bout, whether RT or HIIT, elevates myokines and suppresses breast cancer cell growth in vitro, with greater effects after 12 weeks of training (trained individuals). RT and HIIT showed comparable outcomes, highlighting that regular exercise enhances myokines with anti-cancer properties and reduces in vitro cell growth.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983096","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":"Strength Training Exercises to Minimize Late Effects of Childhood Leukemia or Lymphoma Among Adolescents: A Multicenter Randomized Controlled Trial.","authors":"Henrik Riel, Mathias Kristiansen, Birgitte Klug Albertsen, Martin Kaj Fridh, Christina Friis Jensen, Hanne Bækgaard Larsen, Mathias Rathe, Stine Svilshave, Ruta Tuckuviene, Clara Vad, Joachim Wiskemann, Pascal Madeleine","doi":"10.1249/MSS.0000000000004144","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004144","url":null,"abstract":"<p><strong>Purpose: </strong>Adolescent cancer survivors (ACS) often have persistent impairments in muscle strength, physical function, and quality of life (QoL). This study investigates the efficacy of strength training compared with low-load circuit training in increasing muscle strength over 16 weeks among ACS.</p><p><strong>Methods: </strong>In this superiority randomized controlled trial (NCT06299722), 46 ACS aged 10-19 years were randomized 1:1 to (1) high-load progressive strength training (STEEL) targeting major muscle groups, or (2) circuit training with aerobic and strength components. Primary outcomes were changes in maximal voluntary isometric contraction (MVIC) in elbow flexion/extension and knee flexion/extension measured by handheld dynamometry from baseline to 16 weeks. Secondary outcomes included a one-repetition maximum (1RM) in the leg press and chest press, quality of life assessed with the PedsQL Core 4.0, and fatigue assessed with the PedsQL Multidimensional Fatigue. Assessments were at baseline, 8, and 16 weeks.</p><p><strong>Results: </strong>There were no statistically significant between-group differences in MVIC at 16 weeks. Increases were observed in both groups. Compared with circuit training, STEEL was associated with greater improvements in leg press 1RM (adjusted mean difference 9.9 kg, 95% CI 0.7 to 19.1, P= 0.036) but not chest press 1RM. STEEL was also associated with better physical functioning (adjusted mean difference 7.4 points, 95% CI 0.7 to 14.0, P=0.030) and fewer sleep/rest challenges (adjusted mean difference: 11.4 points, 95% CI 3.1 to 19.6, P=0.007). No other between-group differences in quality of life were observed.</p><p><strong>Conclusions: </strong>High-load progressive strength training was not superior to circuit training for improving isometric muscle strength among ACS. Both groups demonstrated increased muscle strength over time, underscoring the capacity of structured exercise interventions to mitigate strength deficits in this population.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148969995","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":"Neuromechanical Determinants of Muscle-Specific Hamstring Damage and Hypertrophy across Exercises: An EMG-Informed Modeling Approach.","authors":"Titouan Morin, Valentin Doguet, Antoine Mauget, Baptiste Panhelleux, Théo Brossard, Antoine Nordez, Arnault Caillet, Lilian Lacourpaille","doi":"10.1249/MSS.0000000000004142","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004142","url":null,"abstract":"<p><strong>Purpose: </strong>Even under identical training conditions, synergistic muscles such as the hamstrings can adapt differently, with the most affected muscle varying across exercises. The aim of this study was to determine how differences in muscle alterations and adaptations (muscle damage in the acute experiment and muscle hypertrophy in the chronic experiment) are governed by neuromechanical features of exercises.</p><p><strong>Methods: </strong>Neuromusculoskeletal modelling was used to estimate semimembranosus (SM), semitendinosus (ST) and biceps femoris long head (BFlh) activation, operating length, and force during the isokinetic seated leg curl (ISO, only in acute experiment), Nordic hamstring exercise (NHE) and stiff-leg deadlift (SLD). Muscle damage and hypertrophy were quantified from changes in shear modulus and muscle volume, respectively.</p><p><strong>Results: </strong>In the acute experiment, the ST exhibited the largest shear modulus increase after ISO (+62.2%) and NHE (+33.0%). No significant difference in shear modulus was found between SM (+16.0%), ST (-9.0%) and BFlh (+11.4%) after SLD. In the chronic experiment, hypertrophy was rather localized to the ST in NHE (+24.4%) and to the SM in SLD (+11.2%). For ISO (acute) and NHE (acute and chronic), exercise-induced adaptations were consistent and correlated with greater modeled operating length and force of the ST. However, for SLD, the slightly greater SM adaptation was not explained by between-muscle differences in force. Predictive models identified the most damaged muscle in 82% of cases and the most hypertrophied muscle in 75%.</p><p><strong>Conclusions: </strong>This study indicates that differences between hamstring heads in modeled muscle length, and to a lower extent muscle force, explain muscle-specific damage and hypertrophy induced by knee flexion exercises, but not during SLD. Overall, EMG-informed musculoskeletal modeling provides a promising framework to better under the role of neuromechanical parameters in muscle-specific adaptations.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148969933","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":"Physical Capacities are Differentially Altered in Anorexia Nervosa and Constitutional Thinness.","authors":"Natacha Germain, Margaux Leboulleux, Chloé Exbrayat, Ahmad Noureddine, Leo Feasson, Aurélia Gay, Baptiste Ravey, Catherine Massoubre, Guillaume Y Millet, Bogdan Galusca, David Hupin","doi":"10.1249/MSS.0000000000004143","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004143","url":null,"abstract":"<p><strong>Introduction: </strong>Physical capacities partly depend on body mass and composition. Anorexia nervosa (AN) and constitutional thinness (CT) are two distinct low-weight conditions with different muscle phenotypes. While AN is associated with impaired physical performance, this remains unclear in CT. This study aims to directly compare physical capacities in women with AN, CT, and normal-weight controls (CON).</p><p><strong>Methods: </strong>84 women (29 AN, 24 CT, 31 CON) were recruited. Measurements included baroreflex sensitivity, handgrip and leg extension strength, cardiopulmonary exercise testing, and subjective fatigue evaluation FACIT-F questionnaire. A subset (7 AN, 6 CT, 15 CON) also underwent quadriceps-intermittent-fatigability (QIF) test of knee extensor muscles.</p><p><strong>Results: </strong>DXA-derived fat-free mass (FFM) was higher in AN than in CT. Lower body maximal strength, normalized to bodyweight, was lower in AN and CT compared to CON, and similar in AN and CT. VO2peak (% predicted) was lower (p<0.0001) in AN (86.5±24.1%) and CT (80.4±14.6%) than in CON (104.2±24.0%). Maximal aerobic power (MAP) was lower in AN (112.4±37.4W) and CT (92.2±19.7W) than in CON (151.5±37.3W, p=0.0009 and p<0.0001, respectively) and lower in CT than AN (p=0.023). FFM-normalized VO₂peak and MAP did not differ significantly between AN and CT. Peak lactate was lower in AN and CT vs. CON, and lower in CT than AN. Subjective fatigue was greater in AN and CT than in CON. CT completed fewer QIF stages than CON.</p><p><strong>Discussion: </strong>This study demonstrates lower aerobic and muscular capacities in both AN and CT. AN-related deficits may result from undernutrition. CT-related alteration may reflect lower mass and specific phenotype of skeletal muscle, reduced exercise conditioning remaining a possible but unproven contributor. Tailored physical interventions may improve outcomes in both conditions.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148969945","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":"Fractal Correlation Properties of Heart Rate Variability Differentiates Training Intensity During and After Energy-Matched Cycling Sessions.","authors":"Anton Olieslagers, Yoram Müller-Jabusch, Jens De Maeseneer, Maura Seynaeve, Toon T de Beukelaar","doi":"10.1249/MSS.0000000000004146","DOIUrl":"https://doi.org/10.1249/MSS.0000000000004146","url":null,"abstract":"<p><strong>Introduction/purpose: </strong>Recovery optimization requires precise monitoring of physiological stress. This study examines whether detrended fluctuation analysis alpha 1 (DFAa1), a non-linear heart rate variability index, exhibits intensity-dependent responsiveness across energy-matched training sessions in cycling.</p><p><strong>Methods: </strong>Nineteen endurance-trained male participants (18-35yrs) completed three equalized workload protocols at different intensities: light (LIGHT), moderate (MOD), and high-intensity interval training (HIIT). Training sessions were matched for energy expenditure by adjusting time via the formula E=P×Δt (E=Energy (J); P=power (W); Δt=time (s)). LIGHT and MOD training were conducted at first and second lactate threshold power (i.e. LT1 and LT2), respectively. HIIT followed a 10x1min protocol at 110% V̇O₂peak power, alternated with 1min rest at 80% LT1 power. Heart Rate (HR) and DFAa1 were assessed throughout the different intensity training sessions as well as during a standardized 10min warm-up (WU) and cool-down (CD) at LT1.</p><p><strong>Results: </strong>DFAa1 showed apparent stability during LIGHT (p=0.997) and MOD sessions (p=1.000), while showing deterioration during HIIT (p<0.001). On the other hand, HR drift was apparent for all intensities (LIGHT: p=0.003; MOD: p<0.001; HIIT: p<0.001). When directly comparing DFAa1 and HR via ΔZ-scores, a significant effect was found only in MOD (p=0.008). Interestingly, DFAa1 demonstrated significant WU to CD differences for MOD and HIIT (p<0.001), but not for LIGHT (p=0.210), while HR responses showed significant WU to CD differences for all intensities (p<0.001). ΔZ-scores showed significant differences between DFAa1 and HR in MOD (p=0.039) but no significant differences in LIGHT (p=0.098) and HIIT (p=0.071).</p><p><strong>Conclusions: </strong>These findings seem to reinforce that DFAa1 holds promise as an objective, system-wide marker of internal workload across varying exercise domains.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148969938","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}