Med Sci Sports Exerc [JOURNAL]
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200 papers
The Khamis-Roche Percentage of Predicted Adult Height as a Measure of Somatic Maturation: A Scrutiny of Fundamental Simple Ratio Scaling Assumptions.
Lolli L
Med Sci Sports Exerc · 2026 May · PMID 42118916 · Publisher ↗
PURPOSE: To scrutinize the fundamental assumptions that underpin the formulation of the Khamis-Roche percentage of predicted adult height as the simple ratio of standing height (numerator) divided by the Khamis-Roche pre...
PURPOSE: To scrutinize the fundamental assumptions that underpin the formulation of the Khamis-Roche percentage of predicted adult height as the simple ratio of standing height (numerator) divided by the Khamis-Roche predicted adult height (denominator) for assessing maturity status in youth athletes. METHODS: A secondary data analysis of publicly available, de-identified, cross-sectional data relevant to 139 male youth soccer players (age range, 12.2 to 15.2 yr). Assumptions for accurate simple ratio scaling are satisfied if the bivariate regression line between the numerator and denominator passes through the origin, the ratio of the numerator and denominator coefficient of variations (CV x /CV y ) equals the correlation coefficient between these variables, and the relationship between the ratio and its denominator yields a zero correlation. RESULTS: The y-intercept value of -62 cm (95% confidence interval [CI], -99 to -25 cm) from the linear regression between standing height and Khamis-Roche predicted adult height indicated violation of the zero y-intercept assumption. The correlation coefficient between standing height and Khamis-Roche predicted adult height of 0.72 (95%CI, 0.63 to 0.79) was not equal to the ratio of coefficient of variations between these variables (CV x /CV y = 0.52), indicating the failure to meet the proportionality assumption. The positive, non-zero correlation between the ratio and the denominator of 0.28 (95%CI, 0.12 to 0.42) suggested that the Khamis-Roche percentage of predicted adult height was biased low for players with generally shorter predicted adult height, and vice versa . CONCLUSIONS: The percentage of predicted adult height, whether determined using the Khamis-Roche method or any alternative protocol, is an inconsistent simple ratio statistic for assessing maturity status, with the potential to bias the understanding of completed growth in adolescents.
The Cumulative Effects of Three Consecutive Days of Simulated Occupational Heat Stress on Physiological Strain in Young Adults.
Moore DC, Notley SR, Corrigan SL … +2 more , Aisbett B, Main LC
Med Sci Sports Exerc · 2026 May · PMID 42118912 · Publisher ↗
PURPOSE: Many workers complete prolonged shifts (≥8 h) across consecutive days in the heat, yet it is unclear whether this produces cumulative increases in physiological strain that must be considered in heat safety guid...
PURPOSE: Many workers complete prolonged shifts (≥8 h) across consecutive days in the heat, yet it is unclear whether this produces cumulative increases in physiological strain that must be considered in heat safety guidance. This study quantified physiological strain across three consecutive days of simulated occupational heat stress in physically active, young adults. METHODS: Twenty participants (15 males, 5 females) were recruited to complete two 74-h trials in a randomized cross-over design trial. Each trial spanned four consecutive days. Days 1-3 involved baseline measurements (07:00-08:30h), an ~8-h work shift (08:30-16:00h) and an at home recovery (16:00-07:00h [+1 day]). Day 4 involved a final measurement period (07:00-08:00h). Work shifts involved cycles of 30 min work (~367W; ~4.3METs) and 30 min seated rest in summer clothing. Each trial differed only by environment during the work shifts: hot (35°C; 63%RH; 31°C WBGT) or control (18°C; 53%RH; 14°C WBGT). Core temperature, heart rate, mean skin temperature, fluid balance, and perceptual responses were assessed at baseline and end-of-shift. RESULTS: End-of-shift core temperature, core temperature area under the curve, heart rate, and mean skin temperature were higher in hot versus control (all p ≤. 003). However, with the exception of heart rate, which was 20 (95% CI; [12, 27]) beats·min⁻¹ lower on day 3 versus day 1 in the hot condition (p =.018), no outcomes differed across days in hot or control conditions (p ≥.182). CONCLUSIONS: Although there is still a need for larger studies with more protracted exposures in other populations. These findings indicate that there are minimal cumulative physiological effects of three consecutive days of moderate-intensity work in the heat in young, physically active adults.
Static Muscular Stretching Improves Microvascular Function in the Calf Muscles of Patients with Peripheral Artery Disease.
Chen LS, Lanka SP, Alsabbagh Y … +10 more , Nussbaum S, Sarmiento J, Maraj J, Scheuermann B, Ade C, Proctor DN, Farres H, Hakaim A, Hotta K, Muller-Delp J
Med Sci Sports Exerc · 2026 May · PMID 42116234 · Publisher ↗
PURPOSE: Supervised walking exercise is a critical component of rehabilitation for patients with peripheral artery disease (PAD); however, various barriers could limit participation in such programs, highlighting the nee...
PURPOSE: Supervised walking exercise is a critical component of rehabilitation for patients with peripheral artery disease (PAD); however, various barriers could limit participation in such programs, highlighting the need for accessible exercise strategies that may facilitate a gradual transition to more intensive physical activity while improving vascular function and walking performance in this population. We examined the hypothesis that static muscular stretching would improve microvascular function and walking ability in patients with PAD. METHODS: Thirty-six PAD patients, classified as Fontaine Stage II or III, were randomized into stretching or non-stretching groups. The stretching group performed daily calf stretching using an ankle dorsiflexion splint for 30 minutes, 5 days a week, for 4 weeks. The six-minute walk test (6MWT) and a vascular occlusion test were used to assess changes in walking ability and calf microvascular function before and after the intervention. RESULTS: Microvascular hyperemic reperfusion significantly increased in the treatment group (4958±1111 to 5749±1459 %*s, p=0.034), with no change observed in the control group (5502±1231 to 5022±1160 %*s, p=0.155). 6MWT total walking distance increased in all participants (260±88 to 285±85 m, p=0.004). A moderate but non-significant correlation was observed between the changes in 6MWT and total walking distance and reperfusion index in the treatment group (r=0.45, p=0.26). CONCLUSIONS: Static muscular stretching improves microvascular perfusion in the calf muscles, which may contribute to improvement in walking ability in patients with PAD. This low-cost and time-saving intervention may serve as a gradual transition to traditional supervised walking exercise rehabilitation, especially in patients with severely impaired walking ability.
Physical Activity Since Childhood and its Association qith Changes in Midlife Cognitive Functions: A Longitudinal Prospective Cohort Study.
Syväoja HJ, Suominen TH, Kukko T … +16 more , Heiskanen MA, Nevalainen J, Pahkala K, Yang X, Mykkänen J, Viikari J, Juonala M, Kähönen M, Laitinen TP, Tossavainen P, Jokinen E, Lehtimäki T, Ahola-Olli A, Raitakari OT, Rovio SP, Tammelin TH
Med Sci Sports Exerc · 2026 May · PMID 42090606 · Publisher ↗
PURPOSE: . To examine whether cumulative PA in youth, adulthood, or from childhood to midlife is associated with cognitive changes in midlife. We further investigated whether cumulative PA in youth or adulthood was indep...
PURPOSE: . To examine whether cumulative PA in youth, adulthood, or from childhood to midlife is associated with cognitive changes in midlife. We further investigated whether cumulative PA in youth or adulthood was independently related to cognitive changes, and whether these associations differed by sex. METHODS: . This study utilized data (n=1353, 57% females) from the longitudinal, population-based Cardiovascular Risk in Young Finns Study, initiated in 1980. Cognitive functions (learning and memory, working memory, reaction time, and information processing) were evaluated using the Cambridge Neuropsychological Test Automated Battery in 2011 and 2018. PA was assessed with a standardized questionnaire in all study phases (1980-2018), with repeated measurements conducted at 3-9‑year intervals. Cumulative PA was determined for youth (ages 9-24), adulthood (ages 24-48), and life-course (ages 9-48). Associations were analyzed using linear regression models with standardized variables, adjusted for age, education, cardiometabolic risk factors, health behaviors, and a polygenic risk score for cognitive function. Models of cumulative PA in youth and adulthood were additionally adjusted for each other. RESULTS: . Higher life-course PA was associated with a smaller decrease in information processing in midlife (β=0.08, p=0.003) (each unit increase in PA corresponded to a predicted 3-year advantage in information processing). Moreover, higher life-course PA was associated with a smaller decrease in working memory among males (β=0.09, p=0.040) (a predicted 2.7-year advantage in working memory). Life-course PA was not associated with other cognitive functions. Youth PA showed no association with cognitive changes after adjusting for adulthood PA, and vice versa. CONCLUSIONS: The results suggest that individuals with higher life-course PA experience a smaller decrease in executive aspects of cognitive function during midlife.
From Fitness to Cognition: Machine-Learning Prediction of Cognitive Performance Using Physiological Parameters in Healthy Adults.
Yu TC, Wu WL, Ho WH … +2 more , Chang YK, Chu IH
Med Sci Sports Exerc · 2026 May · PMID 42090601 · Publisher ↗
INTRODUCTION: Current cognitive tasks are not suitable for frequent monitoring of cognitive function in healthy adults. Increasing evidence suggests that cardiorespiratory fitness, cardiovascular function, and autonomic...
INTRODUCTION: Current cognitive tasks are not suitable for frequent monitoring of cognitive function in healthy adults. Increasing evidence suggests that cardiorespiratory fitness, cardiovascular function, and autonomic regulation are associated with cognitive performance; however, these multidimensional relationships are challenging to interpret using traditional statistical methods. The present study examined the feasibility of using fitness-related physiological and cardiac autonomic indicators, together with interpretable machine-learning approaches, to assess relative cognitive performance in healthy adults. METHODS: In a cross-sectional sample of 240 adults, 39 physiological variables were recorded as input features. Trail making test completion time was dichotomized at the median as the outcome variable. Four feature-selection strategies, correlation, mutual information, genetic algorithms, and recursive feature elimination, were combined with grid-tuned classifiers under stratified 5-fold cross-validation and probability calibration. RESULTS: A random forest model with ten RFE-selected features achieved 70.83 % accuracy, 71.38 % F1, and AUC = 71.2%, outperforming an untuned logistic-regression baseline model. SHAP-based interpretation indicated that older age, higher systemic vascular resistance, and higher resting heart rate shifted predictions toward the longer TMT-time group, whereas greater stroke volume, cardiac output, high-frequency power, and respiratory sinus arrhythmia shifted predictions toward the shorter TMT-time group. CONCLUSIONS: Physiological parameters related to cardiovascular and autonomic function showed moderate ability to discriminate relative TMT-based performance groups in healthy adults, supporting the feasibility of physiology-based cognitive assessment. Several key features identified by the model are modifiable through exercise and lifestyle interventions, suggesting potential translational value. With further validation and refinement, including evaluation of wearable-accessible physiological features, such models may support lower-burden monitoring and future personalized cognitive-health applications.
Postural Instability Is Greater in Men with Type 2 Diabetes Following Exertional Heat Stress.
Wee J, Low S, Tan XR … +3 more , Leow MKS, Eriksson JG, Lee JKW
Med Sci Sports Exerc · 2026 May · PMID 42081289 · Publisher ↗
PURPOSE: Individuals with type 2 diabetes (T2D) face a greater risk of heat-related illness during exercise compared to healthy counterparts. Here, we examined how T2D affects thermoregulation and post-exercise postural...
PURPOSE: Individuals with type 2 diabetes (T2D) face a greater risk of heat-related illness during exercise compared to healthy counterparts. Here, we examined how T2D affects thermoregulation and post-exercise postural sway in cool and warm-humid environments. METHODS: Middle-aged men with (n=15, age: 58±5 years, V̇O2peak: 31±6 ml/kg/min) and without T2D (CON) (n=15, age: 58±4 years, V̇O2peak: 34±6 ml/kg/min) walked for an hour at 6.0 W/kg in 22 °C, 50%RH (COOL) and 32 °C, 70%RH (WARM) in a randomised counterbalanced crossover design. Gastrointestinal temperature (Tgi), skin temperatures (Tsk), heart rate (HR) and whole body sweat rate (WBSR) were assessed in this study. Postural balance (i.e., centre of pressure (COP) excursions), handgrip strength and five-time sit-to-stand performance were assessed pre- and post-exercise. RESULTS: Men with T2D showed greater increase in postural instability, particularly when balancing on an unstable surface after WARM compared to COOL, despite similar post-exercise Tgi, Tsk, HR, and WBSR between groups. Anteroposterior COP (WARM>COOL: +9mm [95% CI: 3 to 15mm], d = 0.86, P = 0.037); total COP excursion (WARM>COOL: +126mm [95% CI: 48 to 204mm], d =0.87, P = 0.018), and COP mean velocity (WARM>COOL: +5mm/s [95% CI: 2 to 7mm/s], d = 1.49, P = 0.003) were increased only in men with T2D in WARM. CONCLUSIONS: Postural instability increased only in middle-aged men with T2D in humid heat, despite comparable thermoregulatory responses with age-matched men without T2D. This may be attributed to T2D-associated impairments (e.g., altered hemodynamics and/or vibrotactile sensitivity) which can lead to an increased fall risk during or after exercise in the heat.
Effects of Youth Sport Participation on Neural Processing During Response Inhibition in Children.
Leskow J, Jahn A, Shih CH … +1 more , Varangis E
Med Sci Sports Exerc · 2026 Apr · PMID 42081281 · Publisher ↗
PURPOSE: Youth sports offer many benefits to developing children, but collision sports introduce additional risks from exposure to repetitive head impacts (RHIs). Past research has linked this exposure to reduced cogniti...
PURPOSE: Youth sports offer many benefits to developing children, but collision sports introduce additional risks from exposure to repetitive head impacts (RHIs). Past research has linked this exposure to reduced cognitive performance, including response inhibition. The current study aimed to probe how participation in collision sports affects inhibitory control in current youth collision sport athletes, compared to peers who participate in non-contact sports or non-sport activities. METHODS: We used functional magnetic resonance imaging (fMRI) data acquired in the context of a response inhibition (CARIT) task from the Lifespan Human Connectome Project Development (HCP-D) Study to investigate how inhibitory control processing may differ among three groups: youth athletes who currently participate in non-contact sports (n=70; 13.2±2.7 yrs), youth athletes who currently participate in collision sports (n=48; 12.9±2.6 yrs), and current youth participants of non-sport activities (n=57; 14.3±2.5 yrs). Group differences on task-based behavioral measures (accuracy, reaction time) were assessed using generalized linear models (GLMs). A whole-brain univariate fMRI analysis using a GLM approach was conducted to identify task-related regional differences in Blood Oxygenation Level Dependent signal. RESULTS: No group differences were observed in behavioral task performance (p-values above 0.242). However, there were differences in neural recruitment of the left Superior Temporal Gyrus region (MNI: -58, -40, 10; k = 102 voxels; peak voxel z-value = 4.24; p <. 001, cluster-corrected) when comparing the two sport groups to the non-sport activity group - athletes activated this region more than non-sport peers during inhibited response trials. CONCLUSIONS: Sport participation may influence differential processing during active response inhibition, perhaps signaling differences in task strategy, however collision sport participation shows no distinct deleterious effect.
No Influence of Menstrual Phase on Substrate Oxidation Following Submaximal Aerobic Exercise in the Fed State.
Tucker JAL, Bornath DPD, McCarthy SF … +1 more , Hazell TJ
Med Sci Sports Exerc · 2026 Apr · PMID 42081265 · Publisher ↗
INTRODUCTION: Recently the influence of the menstrual cycle and more importantly, fluctuations in key sex hormones across the follicular (FP), ovulation (OP) and luteal (LP) phases have on during exercise substrate oxida...
INTRODUCTION: Recently the influence of the menstrual cycle and more importantly, fluctuations in key sex hormones across the follicular (FP), ovulation (OP) and luteal (LP) phases have on during exercise substrate oxidation has been questioned. In addition to a significant amount of work not following best practices when determining menstrual phase, the inter- and intra-individual variability in hormonal concentrations across cycles may be affecting our understanding. PURPOSE: To examine the effect of three hormonally distinct phases of the menstrual cycle (FP, OP, LP) on during and post-exercise substrate oxidation following an acute bout of submaximal aerobic exercise in the fed state while utilizing best practices to determine menstrual phase. METHODS: Thirteen females (age: 24±4 y, BMI: 24.8±5.4 kg·m -2, V̇O2max: 41.02±5.30 mL·kg·min -1) completed 30 min of submaximal aerobic exercise in the FP, OP, and LP where menstrual phase was tracked using cycle counting, oral body temperature, ovulation strips, and blood sampling. Between-phase differences in respiratory exchange ratio (RER), substrate oxidation, oxygen consumption (V̇O2), overall session O2, and post-exercise metabolism were compared using a series of linear mixed models (LMMs; timepoint x phase). RESULTS: There were no between-phase differences in V̇O2, overall session O2, post-exercise metabolism, or RER (P>0.119, R 2<0.993). There were also no between-phase differences in fat (P=0.417, R 2=0.920) or carbohydrate oxidation (P=0.235, R 2=0.845) during or post-exercise. CONCLUSIONS: These findings demonstrate no differences across menstrual phase in during and post-exercise metabolism following an acute bout of submaximal exercise.
Comparison of Post-Exercise Lipid Oxidation Rates Between Lower and Upper-Body Resistance Training in Well-Trained Females.
Parten AL, Smith-Ryan AE, Sanchez KM … +5 more , Heard SA, O'Neal EK, McAllister MJ, Lyons TS, Waldman HS
Med Sci Sports Exerc · 2026 Apr · PMID 42081260 · Publisher ↗
INTRODUCTION: Lipid oxidation (LOx) is a relevant physiological process linked to metabolic health. Despite growing interest in resistance training (RT) as a means to influence substrate utilization, LOx responses in fem...
INTRODUCTION: Lipid oxidation (LOx) is a relevant physiological process linked to metabolic health. Despite growing interest in resistance training (RT) as a means to influence substrate utilization, LOx responses in females remain poorly characterized, with no study examining whether lower- and upper-body RT elicits different LOx patterns during the recovery period following exercise. This distinction may be relevant because lower-body exercises involves greater fat-free mass (FFM) and energy expenditure, whereas upper-body exercises recruit less FFM, potentially influencing metabolic effects. PURPOSE: To determine if LOx rates after exercise differ between lower- and upper-body RT in well-trained females. METHODS: Twenty-two females (age: 25.4±5.6years, FFM: 44.5±4.9kg, mean relative strength: 1.1±0.2) completed repetition-maximum (RM) tests in the barbell back squat (BS) and bench press (BP). From these, an equated volume-load (sets×repetitions×load) was determined using 65%1RM of participants' BS and BP. Metabolic testing was completed before either the BS or BP, then immediately (IP), 30-, 60-, and 90-min post-exercise. RESULTS: No significant differences were found between BS or BP LOx rates (p>0.05). LOx relative to FFM averaged 1.57±0.4 mg·kg⁻¹FFM·min⁻¹ across both exercises from IP to 90-min post-exercise, representing a 45% and 65% increase from baseline in the BP and BS, respectively. At 90-min post-RT, LOx reached 1.78±0.37mg·kg⁻¹FFM·min⁻¹ (SEM=0.08) for the BS and 1.65±0.31mg·kg⁻¹FFM·min⁻¹ (SEM=0.07) for BP, with no between-condition differences (p>0.05). Resting energy expenditure (REE) was not different between conditions (p>0.05), with a pooled average of 1.04±0.13kcal·min⁻¹ from IP to 90-min post-RT. CONCLUSIONS: These data demonstrate that RT, differing in FFM but not volume-load, stimulates comparable LOx rates and REE responses during the post-exercise recovery period. These findings support versatility in exercise prescription, indicating that RT of different muscle regions can produce similar acute metabolic outcomes.
Compositional Structure of 24-Hour Movement Behaviors Moderates Neurocognitive Responses to Acute Aerobic Exercise in Healthy Adults: A Multimodal Investigation.
Gu Q, Khwang LY, Huang T … +3 more , Zou L, Ai J, Teo WP
Med Sci Sports Exerc · 2026 Apr · PMID 42046231 · Publisher ↗
BACKGROUND: Acute aerobic exercise can transiently enhance executive function (EF) by modulating prefrontal neural activity, yet substantial inter-individual variability in these effects suggests differences in neuroplas...
BACKGROUND: Acute aerobic exercise can transiently enhance executive function (EF) by modulating prefrontal neural activity, yet substantial inter-individual variability in these effects suggests differences in neuroplasticity and responsiveness. However, it remains unclear how habitual 24-hour movement behavior composition, encompassing sleep, sedentary behavior (SB), and light and moderate-to-vigorous physical activity (LPA and MVPA) levels, may shape this baseline neurocognitive state, thereby influencing responsiveness to an acute exercise stimulus. METHODS: Sixty-eight healthy young adults (26.90 ± 3.44 years) completed a single 10-min bout of moderate-intensity cycling. Response inhibition and working memory were assessed using computerized Stroop and N-back tasks. Prefrontal cortex activation and resting-state functional connectivity were measured using functional near-infrared spectroscopy (fNIRS), and corticospinal excitability and intracortical inhibition were assessed using single- and paired-pulse transcranial magnetic stimulation (TMS), before and after exercise. Time spent in sleep, SB, LPA, and MVPA was recorded over 7 consecutive days using wrist-worn accelerometers. Two analytic approaches were applied: (1) latent profile analysis to classify participants into movement behavior profiles and examine pre-post changes using linear mixed-effects models, and (2) continuous compositional regression using isometric log-ratio transformation to examine associations between 24-hour movement composition and neurocognitive outcomes, adjusting for age, sex, and BMI. RESULTS: Habitual movement behavior composition was associated with baseline EF. Participants with more active movement profiles (higher MVPA and lower SB) demonstrated superior EF at baseline, particularly under higher cognitive demand (incongruent Stroop and 2-back tasks). Acute aerobic exercise was associated with improvements in executive performance and prefrontal neurophysiology across all behavioral profiles, with no significant time × group interactions. Task-evoked increases in prefrontal activation and profile-specific alterations in resting-state functional connectivity were observed following exercise. Continuous compositional analyses indicated that higher relative proportions of LPA and MVPA were associated with better working memory performance, whereas higher SB was associated with reduced prefrontal functional connectivity. No significant group-level changes in corticospinal excitability or intracortical inhibition were detected. CONCLUSIONS: Habitual 24-hour movement behavior composition was primarily associated with baseline EF and prefrontal network organization, whereas acute neurocognitive responses to moderate-intensity exercise were largely preserved across behavioral compositions. These findings underscore the importance of considering daily movement context when interpreting individual differences in exercise-related neurocognitive responses.
Neural Responses to Prior and Kinematic Information During Action Anticipation Vary with Expertise: fMRI Evidence from Activation and Connectivity.
Huang Y, Wang D, Liu C … +1 more , Luan M
Med Sci Sports Exerc · 2026 Apr · PMID 42046219 · Publisher ↗
INTRODUCTION: Action anticipation depends on both prior information and incoming kinematic cues, yet how their neural effects vary as a function of motor expertise remains unclear. METHODS: We used fMRI to compare expert...
INTRODUCTION: Action anticipation depends on both prior information and incoming kinematic cues, yet how their neural effects vary as a function of motor expertise remains unclear. METHODS: We used fMRI to compare expert basketball players (n = 42) and non-athlete controls (n = 40) during a sport-specific anticipation task in which probabilistic prior cues preceded temporally occluded basketball shots. Priors were either absent or provided and, when provided, were congruent or incongruent with the subsequent outcome, enabling dissociation of prior availability and prior-kinematic congruency across cue and action observation stages. RESULTS: Behavioral results showed that athletes were more accurate overall, but expertise advantages were condition-specific. Group differences emerged when priors were absent or incongruent with the observed kinematics, whereas performance was comparable when priors were congruent. fMRI results showed that whole-brain and ROI analyses linked prior information and prior-kinematic conflict to distributed fronto-parietal regions implicated in action anticipation, with the left supplementary motor area (SMA) exhibiting reliable sensitivity to both prior availability and prior-kinematic congruency during action observation. Connectivity analyses further showed robust expertise-dependent effects that were not fully captured by regional activation alone. Athletes exhibited stronger SMA-centered coupling with posterior parietal and occipito-temporal regions, particularly under prior-kinematic conflict, along with broader enhancements in task-dependent connectivity among core nodes of the action observation network, whereas controls showed comparatively limited and more posteriorly focused connectivity effects. CONCLUSIONS: Together, these findings suggest that motor expertise is associated with network-level differences in how prior information and kinematic cues contribute to action anticipation, with SMA-centered coordination emerging as a prominent feature of these effects.
Evaluating a Genome-Wide Polygenic Score for Handgrip Strength and its Interplay with Leisure-Time Physical Activity Across the IGEMS Twin Cohorts.
Herranen P, Palviainen T, Nygaard M … +11 more , Karlsson IK, Thalamuthu A, Mather KA, Reynolds CA, Panizzon MS, Rantanen T, Finkel D, Gatz M, Pedersen NL, Kaprio J, Sillanpää E
Med Sci Sports Exerc · 2026 Apr · PMID 42046213 · Publisher ↗
BACKGROUND: Polygenic scores (PGSs) may help assess genetic predisposition to multifactorial traits. We examined whether age, sex, and leisure-time physical activity (LTPA) modify the association between a PGS for handgr...
BACKGROUND: Polygenic scores (PGSs) may help assess genetic predisposition to multifactorial traits. We examined whether age, sex, and leisure-time physical activity (LTPA) modify the association between a PGS for handgrip strength (HGS) and measured HGS in older adults. METHODS: PGS for HGS (PGShgs), based on Pan-UK Biobank GWAS data, was calculated for 5103 participants (aged 40-96; 44% women) from eight twin cohorts in Denmark, Sweden, Australia, the United States, and Finland within the IGEMS consortium. Sex-standardized HGS and self-reported LTPA were assessed cross-sectionally. Linear mixed models estimated associations between PGShgs and HGS, including interactions with age, country, and LTPA, as well as an association between PGShgs and LTPA. Fixed-effect within-pair models were conducted to assess environmental contributions. RESULTS: Higher PGShgs was associated with greater HGS (β = 2.14, SE = 0.15, p < 0.001), explaining 4.6% of HGS variance overall, with modest variation across countries. In sex-stratified models, PGShgs explained 5.2% of the variance in females and 4.3% in males. No statistically significant interaction with age was found. A significant PGShgs × LTPA interaction (β = -0.034, p = 0.013) indicated that the association between LTPA and HGS was more pronounced among individuals with lower PGShgs. The within-pair models offered limited support for the independent environmental impact of LTPA. CONCLUSIONS: The PGShgs was associated with measured HGS in the meta-analysis, highlighting the potential of PGSs to capture individual differences in strength-related traits across populations. The association of PGShgs with HGS was moderated by LTPA, such that the beneficial impact of LTPA on HGS was greater among individuals with a lower genetic propensity for HGS.
When Size Goes Inside: Visceromegaly in Bodybuilders Is Not Attributed to High Protein Intake but More Likely Associated with the Use of Appearance- and Performance-Enhancing Drugs.
Fuchs CJ, Brauwers B, Trommelen J … +5 more , Yildiz S, Widholm P, Leinhard OD, Prompers JJ, van Loon LJC
Med Sci Sports Exerc · 2026 Apr · PMID 42044299 · Publisher ↗
BACKGROUND: Bodybuilders use progressive resistance exercise training and high protein intake diets to develop muscular physiques. Some also use appearance- and performance-enhancing drugs (APED) to further enhance their...
BACKGROUND: Bodybuilders use progressive resistance exercise training and high protein intake diets to develop muscular physiques. Some also use appearance- and performance-enhancing drugs (APED) to further enhance their physique. It has been speculated that a high protein intake and/or APED use may induce visceral organ hypertrophy. Therefore, the primary objective of this study was to assess visceral organ volumes in natural and APED-using male bodybuilders and to compare these with recreationally active males. METHODS: Magnetic Resonance Imaging (MRI) was applied to assess skeletal muscle and visceral organ volume in 15 recreationally active males (CON; age: 29±6 y), 15 competitive male natural bodybuilders (BB-NAT; age: 30±5 y), and 15 competitive male APED-using bodybuilders (BB-USE; age: 31±4 y). In addition, Dual-energy X-ray Absorptiometry (DXA) was performed to assess total body lean mass. All participants reported their habitual food intake (via 7-day food diary) and, if applicable, their use of APED. RESULTS: Habitual protein intake was much higher in the bodybuilders (BB-NAT: 2.5±0.6 g/kg body mass/d; BB-USE: 2.9±0.4 g/kg body mass/d) compared to CON (1.4±0.3 g/kg body mass/d; P<0.001), with no differences between both bodybuilder groups (P=0.109). Total lean body mass was significantly different across all groups and was greater in BB-USE (87.8±8.0 kg) vs BB-NAT (72.7±6.4 kg) vs CON (62.8±4.8 kg; P<0.001). Muscle volumes were also different between groups, with average thigh muscle volumes of 7.1±1.0, 5.8±0.7, and 4.5±0.4 L in BB-USE, BB-NAT, and CON, respectively (P<0.001). All visceral organ volumes were greater in BB-USE compared with BB-NAT and CON (P<0.05), with no differences between BB-NAT and CON (P>0.05). Heart volume averaged 1.20±0.15, 0.89±0.14, and 0.83±0.15 L in BB-USE, BB-NAT, and CON, respectively. Liver volume averaged 2.57±0.39, 1.82±0.20, 1.79±0.21 L, respectively. CONCLUSIONS: Despite higher habitual protein intake and greater lean body mass, natural bodybuilders do not show greater visceral organ volumes compared to age-matched controls. Bodybuilders using APED show substantially greater lean mass, muscle mass, as well as greater visceral organ volumes compared to natural bodybuilders or age-matched controls. We conclude that visceromegaly in bodybuilders cannot be attributed to a high protein intake but is secondary to the use of appearance- and performance-enhancing drugs.
Limited Sex Differences in Energy Balance and Body Composition during 61+D of US Army Ranger Training.
McClung HL, Oliver TE, Goldenstein SJ … +16 more , Farina EK, Hatch-McChesney A, Giersch GEW, Heaton KJ, Ripperger MR, Greenfield AM, Karis AJ, Bartlett PM, Walker LA, Munoz R, Corona PJ, Sczuroski CE, Zepettelli DJ, Nguyen VT, Oppenheimer AV, Gwin JA
Med Sci Sports Exerc · 2026 Apr · PMID 42044295 · Publisher ↗
INTRODUCTION: Negative energy balance (Ebal) and changes in body composition are common in Soldiers during combat training with increased total daily energy expenditure (TDEE) and restricted food intake. Whether sex diff...
INTRODUCTION: Negative energy balance (Ebal) and changes in body composition are common in Soldiers during combat training with increased total daily energy expenditure (TDEE) and restricted food intake. Whether sex differences exist in those effects is unknown. METHODS: Ebal and body composition (dual-energy X-ray absorptiometry; body mass (BM), fat mass (FM), fat-free mass (FFM)) of Soldiers (10 females:27 males) completing US Army Ranger training course (RTC) were compared by sex before baseline and after each training phase (P1-P3). Doubly labeled water was used to estimate TDEE, food wrappers collection to assess dietary energy intake, and daily activity energy expenditure was calculated. RESULTS: Baseline BM and FFM were lower ( p < 0.01) in females than males, while baseline FM was higher in females than males ( p = 0.01). Body composition differences remained at each phase, except at P3 when no sex difference in FM ( p = 0.15) was detected. Males experienced a greater loss in BM from baseline than females at each phase (all, p ≤ 0.05). Females maintained their FFM to a greater extent from baseline than males at each phase (all, p ≤ 0.01). TDEE was higher in males compared to females in P1 and P2 (both, p < 0.01), but not in P3 ( p = 0.37). Females showed a greater increase in dietary intake from P1 to P2 ( p = 0.004) compared to males. No differences in the change from P1 to P2 or P1 to P3 were detected for TDEE, Ebal, resting energy expenditure or activity energy expenditure. CONCLUSIONS: Despite differences in absolute Ebal, the magnitude of change in Ebal did not differ by sex across RTC. Males lost more BM throughout the long-term course while females preserved FFM to a greater extent than males.
Increased Pre-Activation and Co-Contraction in ACL-Reconstructed Athletes: Insights from AI-based EMG Analysis.
Ghislieri M, Russo F, Borzuola R … +4 more , Baldazzi A, Rum L, Bergamini E, Agostini V
Med Sci Sports Exerc · 2026 Apr · PMID 42044292 · Publisher ↗
INTRODUCTION: Anterior Cruciate Ligament (ACL) tears disrupt the neural structures within the ligament, impairing the neuromuscular control of knee-stabilizing muscles. Consequently, muscle activity patterns are a crucia...
INTRODUCTION: Anterior Cruciate Ligament (ACL) tears disrupt the neural structures within the ligament, impairing the neuromuscular control of knee-stabilizing muscles. Consequently, muscle activity patterns are a crucial area of research in return-to-sport evaluation after ACL Reconstruction (ACL-R). Artificial intelligence-based methods may help identify and extract meaningful parameters from these patterns. This study aims at accurately and reliably quantifying knee muscle pre-activation and timing-based co-contraction indexes in athletes with and without ACL-R during sports-specific landing tasks using an artificial intelligence approach. METHODS: Eleven athletes with ACL-R and 18 Control Athletes (CA) performed two landing tasks: single-leg hop and single-leg cross drop landing. EMG signals were recorded bilaterally from four knee-stabilizing muscles: Biceps Femoris (BF), SemiTendinosus (ST), Vastus Lateralis (VL), and Vastus Medialis (VM). Muscle pre-activation onsets prior to landing and timing-based co-contraction indexes were computed through a pre-trained deep learning-based muscle activity detector (LSTM-MAD). To ensure comparability with state-of-the-art approaches, amplitude-based EMG co-contraction indexes were also computed. RESULTS: LSTM-MAD estimated muscle pre-activation onset with an error under 23 ms compared to manual segmentations by three experts. During single-leg hops, ACL-R athletes exhibited significantly greater BF (ACL-R: -193±12 ms; CA: -152±5 ms; p=0.002) and ST (ACL-R: -189±11 ms; CA: -140±4 ms; p<0.001) pre-activations and longer co-contraction durations (ACL-R: 69±2%; CA: 54±2%; p<0.001) compared to CA. During single-leg cross drop landings, ACL-R athletes showed greater BF (ACL-R: -234±25 ms; CA: -150±11 ms; p=0.02) pre-activations and longer BF and ST co-contractions (ACL-R: 55±5%; CA: 35±2%; p=0.003) compared to CA. At return-to-sport, ACL-R athletes demonstrated greater BF and ST pre-activation and co-contraction during landing tasks. CONCLUSIONS: Integrating artificial intelligence-based methods to assess neuromuscular control could improve the effectiveness of rehabilitation protocols, facilitating safer return-to-sport decisions.
The Effects of Resistance Exercise Training on Visceral White Adipose Lipolytic Pathways in Female Rats.
Sammut MJ, Thorne BR, Saeed L … +2 more , McBey DP, Melling CWJ
Med Sci Sports Exerc · 2026 Apr · PMID 42023985 · Publisher ↗
BACKGROUND: Visceral white adipose tissue (vWAT) accumulation is a key contributor to cardiometabolic disease, particularly in females, yet the impact of resistance exercise training (RET) on vWAT metabolism remains poor...
BACKGROUND: Visceral white adipose tissue (vWAT) accumulation is a key contributor to cardiometabolic disease, particularly in females, yet the impact of resistance exercise training (RET) on vWAT metabolism remains poorly characterized. OBJECTIVE: This study investigated the effects of 10 weeks of RET on visceral adiposity, glycemic regulation, and vWAT lipolytic pathway activation in female rats. METHODS: Female Sprague-Dawley rats (n = 20) were randomized to sedentary (SED; n = 10) or RET (n = 10) groups. RET animals performed weighted ladder climbing 5 days/week for 10 weeks. Weekly body mass and food intake over the final week were recorded. Fasting blood glucose (BG) measurements and intravenous glucose tolerance tests were performed 3-4 days following the final exercise bout. Visceral adipose (gonadal white adipose tissue depot; gWAT) and skeletal muscles were collected 5 days following the final exercise bout and weighed. gWAT samples were used for western blotting of proteins involved in lipolysis and lipid metabolism. RESULTS: RET significantly increased biceps and flexor digitorum longus relative muscle mass and reduced gWAT mass (p < 0.05), without significantly altering body mass. Fasting BG was reduced (p < 0.05) in RET compared to SED animals and strongly correlated with gWAT mass (R = 0.71, p < 0.001), while IVGTT area under the curve was unchanged. RET animals demonstrated enhanced phosphorylation of adipose triglyceride lipase (ATGL) and protein kinase A (PKA) substrates (p < 0.05) in gWAT. CONCLUSIONS: RET enhances basal lipolytic pathway activation in vWAT and improves fasting glycemia independent of body mass. These findings support RET as a weight-neutral strategy to reduce vWAT and improve cardiometabolic health in females.
Infection as an Exertional Heat Illness Risk Factor: A Prospective Cohort Study.
Tyson HC, Zurawlew MJ, Robinson MR … +11 more , Hemingway R, Corbett J, Tipton MJ, Gould AAM, Moore C, Jones R, Pheasant K, Rawcliffe AJ, Izard RM, Roberts AJ, Walsh NP
Med Sci Sports Exerc · 2026 Apr · PMID 42023778 · Publisher ↗
PURPOSE: Strenuous physical activity for work or leisure increases the risk of exertional heat illness (EHI), which can be fatal. Respiratory infection may increase EHI risk, but empirical evidence is equivocal and relie...
PURPOSE: Strenuous physical activity for work or leisure increases the risk of exertional heat illness (EHI), which can be fatal. Respiratory infection may increase EHI risk, but empirical evidence is equivocal and relies upon clinical case reviews that lack objective measures and comparator controls. This prospective cohort study investigated the association between respiratory infection and EHI. METHODS: N=807 UK infantry recruits (M=805/F=2) completed a 6.4-mile loaded march between Spring and Fall (2021-2024, WBGT, 11.2 ± 3.6°C). Participants completed the Jackson Common Cold Questionnaire on each of the 3 days preceding and before the loaded march on Day 0. Additional measures included clinical pathology on throat swabs (Day -3 and -1), serum C-reactive protein (CRP; Day -1) and gastrointestinal temperature (Tgi, Day 0). EHI was classified as mild (exercise-induced headache, dizziness, or nausea) or severe (CNS disturbance plus hyperthermia and/or end-organ damage). Logistic regression examined the association between respiratory infection and EHI after full adjustment for widely considered EHI risk factors. RESULTS: N=118 participants were classified as mild (15%) and N=40 as severe EHI (5%). The likelihood of severe EHI was increased four-fold with respiratory infection symptoms on Day -1 and 0 (OR=4.09, 95% CI=1.29-12.90, P=0.016) and three-fold when restricting analysis to symptoms on Day 0 (OR=2.83, 95% CI=1.02-7.86, P=0.046). Participants with respiratory infection symptoms exhibited increased pathogen expression, systemic inflammation (CRP >3 mg·L -1) and pre-loaded march Tgi (+0.3°C, P=0.023). Respiratory infection symptoms were not associated with mild EHI susceptibility. CONCLUSIONS: Ongoing respiratory infection was associated with an increased likelihood of severe exertional heat illness. Individuals at risk of exertional heat illness (e.g., athletes) should avoid strenuous physical activity when suffering respiratory infection symptoms.
Combination of Intermittent Hypoxic Exposure and Exercise Improves Body Composition and Glucose Tolerance in High-Fat Diet-Induced Obese Mice.
Jang I, Hwang D, Kyun S … +7 more , Park Y, Kim T, Lim K, Hwang H, Park HY, Kim SW, Kim J
Med Sci Sports Exerc · 2026 Apr · PMID 42023775 · Publisher ↗
PURPOSE: To determine the independent effects of moderate-intensity exercise training and intermittent normobaric hypoxic exposure, and whether their combination provides additional improvements in body composition, ener...
PURPOSE: To determine the independent effects of moderate-intensity exercise training and intermittent normobaric hypoxic exposure, and whether their combination provides additional improvements in body composition, energy metabolism, and glucose homeostasis in high-fat diet (HFD)-induced obese mice. METHODS: Male ICR mice were fed an HFD for 7 weeks to induce obesity, then assigned to sedentary normoxia (SED+NOR), sedentary hypoxia (SED+HYP), exercise normoxia (EXE+NOR), or combined exercise plus hypoxia (EXE+HYP) for 5 weeks. Hypoxic exposure was applied under normobaric conditions by reducing inspired oxygen fraction (FiO₂ = 12%) for 12 h/day during the inactive phase, whereas exercise was performed during the active phase as speed-defined moderate-intensity treadmill running (5 d/wk) under normoxia. Body composition was assessed by DXA before and after the intervention. Glucose regulation was evaluated using fasting blood glucose, circulating insulin levels, OGTT, and HOMA-IR. Resting gas exchange and substrate oxidation were assessed to characterize energy metabolism. Skeletal muscle proteins related to substrate metabolism and glucose transport were measured by immunoblotting. RESULTS: Exercise training and intermittent hypoxic exposure improved obesity-associated metabolic impairments via distinct mechanisms. Exercise primarily reduced fat mass and improved glucose tolerance, accompanied by increased skeletal muscle GLUT4 abundance. Hypoxic exposure improved insulin sensitivity and systemic glucose regulation (lower insulin and HOMA-IR), despite limited effects on body weight. Notably, the combined EXE+HYP intervention produced the most pronounced overall improvements, including greater benefits in body composition and resting carbohydrate utilization compared with either intervention alone. In skeletal muscle, EXE+HYP increased oxidative metabolism-related protein expression relative to sedentary HFD controls. CONCLUSIONS: Intermittent normobaric hypoxic exposure and moderate-intensity exercise training provide complementary metabolic benefits in HFD-induced obese mice, and their combination yields additional improvements in key markers of body composition and glucose homeostasis. These findings support integrating hypoxic exposure with exercise as a potential non-pharmacological strategy to optimize metabolic health and motivate further mechanistic and translational studies.
High-Intensity Resistance Training Enhances Strength, But Not Muscle Mass and Physical Functioning Gains During Total Knee Arthroplasty Rehabilitation.
Monsegue AP, Wilms EJC, Kramer CS … +8 more , Morwani-Magnani J, van der Haijden M, Singh-Povel CM, Grootswagers P, de Groot L, Slagboom PE, van Loon LJC, Verdijk LB
Med Sci Sports Exerc · 2026 Apr · PMID 42008941 · Full text
PURPOSE: To determine whether high-intensity resistance exercise training with nutritional support (RET) during recovery from total knee arthroplasty (TKA) induces greater improvements in muscle-related outcomes compared...
PURPOSE: To determine whether high-intensity resistance exercise training with nutritional support (RET) during recovery from total knee arthroplasty (TKA) induces greater improvements in muscle-related outcomes compared to standard rehabilitation alone (SR). METHODS: Thirty-three patients (70±6 y; 28.7±3.1 kg·m -2) were randomized to receive RET (intervention+regular rehabilitation, n=18) or SR (regular rehabilitation only, n=15) for 12 weeks, starting 8 weeks post-TKA. RET involved supervised, bilateral, high-intensity resistance exercise, 3x/week, daily supplementation (45g protein, 5.5 g Vivinal® GOS, 800 IU vitamin D, 366 mg calcium), and dietary counselling. Outcomes included bilateral and unilateral leg press 1RM, DXA-derived appendicular lean mass (ALM), CT-derived quadriceps cross-sectional area (CSA), 6-min walking test (6MWT) and 5-times chair-stand test (5CST). Data are mean±SD, analysed with 2-way repeated-measures ANOVAs, or median [IQR], analysed with Wilcoxon Signed-Rank test. RESULTS: Bilateral leg press 1RM improved to a greater extent following RET (131±38 to 174±56 kg, P<0.001) vs SR (124±36 to 143±49 kg, P=0.018, P-interaction=0.026). Strength in the non-operated leg increased in the RET group only (RET: 22±17%, P<0.001, SR: 6±11%, P=0.175, P-interaction=0.002). Operated leg strength increased similarly between groups (RET: 51±33%, SR: 40±30%, P-time<0.001, P-interaction=0.338), as did ALM (RET: 0.5±0.8 kg, SR: 0.3±0.8 kg, P-time=0.009, P-interaction=0.390), and quadriceps CSA (operated: RET: 7.8±7.5%, SR: 9.2±5.9%, non-operated: RET: 4.8±4.5%, SR: 3.8±3.7%, P-time<0.001, P-interaction≥0.557). 6MWT improved more in the SR (428±94 to 513±75 m, P<0.001) vs RET group (417±69 to 460±72 m, P=0.002, P-interaction=0.034). 5CST only improved significantly following RET (RET: 15.3 [4.2] to 13.2 [3.9] s, P=0.039, SR: 14.4 [4.0] to 14.4 [5.1] s, P=0.064). CONCLUSIONS: Compared to standard TKA rehabilitation, high-intensity resistance training with nutritional support induces greater gains in bilateral strength but not muscle mass or physical functioning.
Erythropoietin and Hematological Responses in Recreational Scuba Divers: Insight into the Hyperoxic-Hypoxic Paradox.
Perović A, Juričić G, Bratičević MN … +3 more , Tomičić N, Žarak M, Dumić J
Med Sci Sports Exerc · 2026 Apr · PMID 42002932 · Publisher ↗
PURPOSE: During scuba diving, breathing under elevated pressure leads to hyperoxia, which may induce oxidative stress and erythrocyte damage. Hyperoxia may also influence erythropoietin (EPO) production, a phenomenon ref...
PURPOSE: During scuba diving, breathing under elevated pressure leads to hyperoxia, which may induce oxidative stress and erythrocyte damage. Hyperoxia may also influence erythropoietin (EPO) production, a phenomenon referred to as the hyperoxic-hypoxic paradox. This study investigated changes in EPO levels and red blood cell (RBC) parameters after (I) a single dive, (II) three successive dives over two days, (III) the summer diving season. METHODS: (I) Divers (N=23) completed a single 30-min dive to 30 m. Blood samples were collected immediately pre- and post-dive, and 3 h post-dive. (II) Divers (N=18) continued with successive 30-min dives, with blood collected immediately pre- and post-dive for each dive. (III) Divers (N=12) with more than 20 summer dives were resampled in September, 21 weeks after the first sampling. RESULTS: No significant changes in EPO concentration were observed immediately post-dive or 3 h post-dive. During successive dives, EPO increased post-dive 2 (P=0.045, 18%), increased further pre-dive 3 (P=0.001, 24%), and reached the highest value post-dive 3 (P<0.001, 34%). After the summer diving season, no significant changes in EPO were observed. Decreases in RBC count, hemoglobin concentration, and hematocrit observed 3 h after a single dive were not observed across successive dives or after regular summer dives. CONCLUSIONS: Three successive dives over two days and regular recreational diving over 21 weeks did not affect RBC count, hemoglobin concentration, or hematocrit. The progressive increase in EPO during successive dives warrants further investigation to clarify the underlying biological mechanisms.
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