Dynamic postural control in Canadian canoeing depends on coordinated load distribution and center of pressure regulation across three support points in a highly asymmetrical kneeling posture. However, the integrated organization of these biomechanical domains under varying stability demands remains poorly characterized. This exploratory study examined 13 Canadian canoeing athletes using three synchronized strain-gauge force platforms during a standardized canoe-specific kneeling position under stable and unstable support conditions. Three dynamic variables, percentage load distribution (%DCA), dynamic force (N. kg⁻¹), and center-of-pressure displacement (Dynamic SigmaPath), were assessed simultaneously. Principal component analysis showed that PC1 (62.5% variance) and PC2 (24.1% variance) captured the main structure of postural control, with Dynamic SigmaPath displaying loading patterns opposite to the percentage load distribution and force. Exploratory K-means clustering (k=2) suggested moderate organization into two biomechanical patterns. Correlation analyses revealed significant associations between load-distribution metrics and Dynamic SigmaPath (ρ=0.657 and p=0.015), and between force production and load-distribution asymmetry (ρ=−0.635 and p=0.020). These findings indicate that biomechanical affinity, quantified through multivariate analysis, characterizes athlete-specific postural-control strategies. A Composite Biomechanical Index is proposed as an exploratory framework for describing postural-control strategies and generating hypotheses regarding athlete monitoring and crew compatibility in paddling sports.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The aim of the current study was to compare modelled maximal lactate steady state with the field-based assessment of critical power in a group of highly trained pro cyclists. As a secondary objective, the relationships of the maximal rate of blood lactate accumulation and maximal oxygen consumption with outdoor maximal mean power output of different durations were explored. Twelve highly trained male professional cyclists performed six successive maximal tests. The maximal lactate steady state was calculated using the maximal rate of blood lactate accumulation, maximal oxygen consumption, resting oxygen uptake and body mass as input parameters. The critical power was estimated using the 3-minute and 20-minute maximal mean power outputs. The mean of the modelled maximal lactate steady state was 357±30.6 W, while the mean of critical power was 364±21.5 W; the modelled maximal lactate steady state and critical power correlated significantly (r=0.881 and p<0.001). The maximal oxygen consumption correlated with the 3-minute maximal mean power (r=0.646 and p=0.023), 20-minute maximal mean power (r=0.846 and p<0.001) and critical power (r=0.858 and p<0.001). No significant correlations were found between maximal rate of blood lactate accumulation and any of the outdoor maximal mean power outputs. The modelled maximal lactate steady state seems to predict critical power well on a group level; however, a substantial individual variation in the difference between the modelled maximal lactate steady state and critical power was observed. This individual variation would argue against conceptual similarity between the critical power and maximal lactate steady state model, which practitioners working within cycling should be aware of.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The association between reduced Achilles tendon structural integrity and ankle instability may reflect alterations in muscle–tendon properties and impairments throughout the lower-extremity kinetic chain following ankle sprain. This study aimed to investigate the effect of an intervention program on Achilles tendon organization in military recruits and to evaluate its impact on tendon structure in participants with ankle instability and those who sustained ankle sprains during training. A total of 387 male recruits (160 intervention and 227 control groups) were screened for Achilles tendon structure (echo types III and IV representing disorganized fibers) at baseline (PRE) and 12 weeks of infantry training (POST). The cohorts reported pre-induction chronic ankle instability and were followed for ankle sprains during training. The intervention group undertook an injury prevention program (5min, five times/wk) while the control group continued their routine physical-fitness sessions. Significanttime×group interactions were found for echo types III and IV fibers (p=0.005 and p=0.032, respectively). The time×instability×groupinteraction was found for echo type IV (p=0.005); the time×instability interaction was found for echo type III (p=0.017). In participants who received exercises, the Achilles tendon structure improved during training. Participants with pre-induction chronic ankle instability and participants who sprained their ankles were more likely to present the disorganized PRE-training tendon structure. Neuromuscular injury-prevention intervention training might be associated with improved tendon quality in those who sprained their ankles during training.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The aim of this study was to analyze the mid- and long-term changes in carotid artery structure and function in amateur marathon runners by applying the vascular quality intima-media thickness technique in conjunction with quantitative arterial stiffness testing. Fifty-five cases of amateur marathon runners recruited in somewhere in 2019 (marathon group) and 43 cases of healthy volunteers in the same period (control group) were included. Two tests were performed on all the subjects (completed in 2019 and 2024, respectively). The quality intima-media thickness technique was used to measure the thickness of bilateral carotid intima-media thickness, and QAS was used to measure the elasticity parameters of the carotid arteries bilaterally, including the dilatation coefficient, compliance coefficient, stiffness coefficients (α and β), and pulse wave velocity. Demographic and clinical data including age, gender, heart rate, blood pressure (systolic and diastolic), body mass index, running age, and monthly running volume were collected from the subjects. We compared the differences in intima-media thickness and elasticity parameters between the two groups and analyzed the medium- and long-term changes in carotid artery parameters between the two groups; a logistic regression model was used to analyze factors associated with changes in intima-media thickness and elasticity parameters in the marathon group after 5 years. During the 5-year study period, comparison between the marathon group 5 years ago and 5 years later and comparison between the control group 5 years ago and 5 years later were performed. Carotid intima-media thickness, α, β, and pulse wave velocity increased, while dilatation coefficient and compliance coefficient decreased, with all differences being statistically significant (p<0.05). In 2019, comparisons between the marathon group and the control group showed no statistically significant differences in intima-media thickness, α, β, pulse wave velocity, dilatation coefficient, or compliance coefficient (p>0.05). The intima-media thickness, α, β, and pulse wave velocity increased and the dilatation coefficient and compliance coefficient decreased in the 2024 marathon group compared with the control group, and the differences were statistically significant (p<0.05). Univariate logistic regression models analyzed the relationship among age, running duration, monthly running volume, and changes in carotid intima-media thickness and elasticity parameters 5 years after marathon participation. Repeatability tests showed good intra- and inter-observer agreement. Marathon exercise leads to thickening and increased stiffness of the carotid intima-media thickness in athletes, and the application of quality intima-media thickness combined with quantitative arterial stiffness allows for early and dynamic visualization of this change.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This randomized controlled trial examined the effects of adding neuromuscular electrical stimulation to rehabilitation exercise on quadriceps muscle strength (primary outcome) and secondary exploratory outcomes after anterior cruciate ligament reconstruction. Twenty-four male participants were randomly allocated to rehabilitation exercise alone or combined with neuromuscular electrical stimulation. Both groups performed range of motion exercises during weeks 1 to 3, followed by progressive quadriceps strengthening three times weekly for 9 weeks. Both groups improved in isokinetic muscle function, with larger effect sizes in the resistance exercise+neuromuscular electrical stimulation group (d=0.883–1.488) than in the resistance exercise group. Patient-reported outcomes improved in both groups for the Lysholm score (d=1.527 vs. 0.653), whereas changes in the International Knee Documentation Committee score were greater in resistance exercise+neuromuscular electrical stimulation (d=1.006 vs. 0.034). Balance improved with larger effects in resistance exercise+neuromuscular electrical stimulation under stable (d=0.710 vs. 0.160) and unstable conditions (d=1.988 vs. 0.029), while Y-balance showed similar changes. Muscle morphology showed greater increases in resistance exercise+neuromuscular electrical stimulation for the cross-sectional area (d=1.127 vs. 0.070) and thickness (d=0.737 vs. 0.203). Biomarker responses were also larger in resistance exercise+neuromuscular electrical stimulation. Overall, the neuromuscular electrical stimulation was associated with favorable trends across several functional and clinical outcomes.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Amenorrhea in female athletes may be associated with cardiovascular disease risk factors. We aimed to implement a rigorous methodology to confirm menstrual status and examine differences in lipid and inflammatory markers between amenorrheic and eumenorrheic adolescent athletes. We included 13–18-year-old participants who were over 1-year post-menarchal and not using hormonal medications. Participants reporting≥9 menstrual periods in the prior year underwent a prospective methodology to be classified as eumenorrheic. Those reporting no menstrual period for more than three consecutive months prior to enrollment were classified as amenorrheic. We compared lipid and inflammatory markers between eumenorrheic and amenorrheic groups. There were 32 participants included (n=12 eumenorrheic; n=10 amenorrheic; n=4 anovulatory; and n=6 oligomenorrheic), with 96.5% adherence to the menstrual tracking protocol. The amenorrheic group demonstrated higher high-density lipoprotein levels (60.8 vs. 52.7; p=0.04) and trended toward lower C-reactive protein levels (0.43 vs. 1.53; p=0.07) than the eumenorrheic group. Amenorrheic athletes did not demonstrate cardiovascular disease risk factors compared with eumenorrheic athletes, contrary to what has been observed in prior studies of adult athletes. We demonstrated feasibility and success in implementing a rigorous methodology to classify and confirm menstrual status in an adolescent athlete population that can be replicated in future studies.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study compared serum irisin concentration changes following 16 weeks of different exercise protocols (hill, running, cycling, and combined) versus control in 289 previously sedentary adults. We identified phenotypic and genetic predictors to establish an irisin response prediction model for precise exercise prescription. Phenotypic measures (serum irisin, maximal oxygen consumption, and lipids) and fibronectin type-III domain containing protein-5 genen single nucleotide polymorphism (rs16835198) genotyping were performed pre/post-intervention. Serum irisin significantly increased post-exercise overall (p<0.05), but with substantial interindividual variability (Δ range:−4.98 to 20.77 ng/mL; 28.03% responders, Cohen’s d≥0.2). Under the specific (and unstandardized) exercise volumes utilized in this study, hill and combined training elicited the most significant increases (p<0.01). Cohen’s d-based irisin change effect size significantly correlated with baseline maximal oxygen consumption (r=0.164 and p<0.01) and irisin levels (r=0.481 and p<0.05). It was also linked to FNDC5 rs16835198 (p=0.041), with the TT genotype exhibiting greater responses than GT/GG genotypes. A model incorporating baseline serum irisin concentrations (β=0.522), maximal oxygen consumption (β=0.107), exercise protocols (β=0.207), and rs16835198 genotype (β=0.116) explained 27.1% of the variance in the effect size of Δirisin. In short, exercise-induced irisin elevation exhibited marked individual variability. Baseline irisin, maximal oxygen consumption, FNDC5 rs16835198 genotype, and exercise protocol are significant predictors, accounting for 27.1% of the individual differences in training response, informing precision exercise prescription. Keywords: Irisin; Individual differences; Effect of exercise intervention; prediction model.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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To set reference descriptives for training purposes, this study analysed the force–velocity profile in elite cyclists, considering sex, category (elite, under 23, and junior), and discipline (bicycle motocross, mountain bikes, road, and track). Elite cyclists (n=107; 53 men, 20.00 [3.78] y and 54 women, 20.76 [4.43] years) underwent force–velocity testing during preseason. Participants performed six squat jumps ranging from 0% to 70% of body weight, measured via a Chronojump Bosco system platform. Outcomes included maximal power, maximal force, maximal velocity, and force–velocity slope. Men reflected higher maximal power (4.32 W·kg−1, 95% confidence interval: 1.11–7.53, p < 0.001) and maximal force (4.57 N·kg−1, 95% confidence interval: 1.77–7.37, p=0.001) than women, with no differences in maximal velocity or force–velocity slope. Bicycle motocross men showed the highest maximal force (p = 0.001) and the steepest force–velocity slope (p = 0.012) relative to other disciplines, pointing to a greater force orientation. No significant between-discipline differences were observed for maximal power (p = 0.519 in men; p = 0.191 in women—including road/mountain bikes/track only) or maximal velocity in either sex. Discipline shapes the squat-jump-derived force–velocity profile in elite cyclists. Whiles gender affects strength and power but not slope or velocity, category is not determinant. The squat force–velocity profile is informative and easy-to-conduct but should be considered individually and complemented with specific testing.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Post-exercise hypotension has been proposed as a promising biomarker for predicting the long-term blood pressure response to exercise training. This study assessed the reliability of post-exercise hypotension—from single- and averaged-session measurements—in 33 sedentary adults completing an 8-week aerobic exercise program. The resting blood pressure was measured before and after the intervention; acute post-exercise hypotension was defined as the change in blood pressure from pre-exercise to 10-minute post-exercise recovery and was measured across five separate sessions. Data were analysed using mixed-effects models. The impact of aggregating measurements on reliability and its correlation with chronic blood pressure reduction was assessed using analytical formulas and Monte Carlo resampling. The reliability of single-session post-exercise hypotension measurements was poor, with a high standard error of measurement (systolic blood pressure: 4.5 [4.0, 5.1] mm Hg and diastolic blood pressure: 4.3 [3.8, 4.9] mm Hg) and low intraclass correlation coefficients (systolic blood pressure: 0.24 [0.08, 0.29] mm Hg and diastolic blood pressure: 0.31 [0.13, 0.43] mm Hg). Reliability improved substantially when values were averaged across multiple sessions. The correlation between acute post-exercise hypotension and chronic blood pressure reduction also strengthened with averaging, albeit with diminishing returns. These findings support the potential of post-exercise hypotension as a predictive biomarker, particularly when averaged over several training sessions. The optimal number of sessions should balance statistical improvement with practical feasibility.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Despite growing research, the health effects of COVID-19 on soccer players remain poorly integrated. This meta-analytic review synthesized evidence across competitive levels and pandemic phases to characterize the effects of SARS-CoV-2 infection and pandemic-related restrictions. The study adhered to PRISMA 2020 and Cochrane standards, with searches conducted in PubMed, Scopus, SPORTDiscus, and Web of Science. Eligibility criteria followed the P.E.C.O.S. framework. From 6,048 records screened, nine studies (>1,525 players from Tiers 1–5) met the inclusion criteria. These observational investigations included predominantly male samples (94.2%) and assessed cardiovascular, respiratory, endocrine, metabolic/biochemical, hematologic, anthropometric, musculoskeletal, and gastrointestinal outcomes. Comparisons between pre- and during-pandemic periods suggested preserved cardiac integrity with infrequent post-infection sequelae, alongside mild pulmonary effects in infected players that tended to resolve with training resumption. Amid inconsistent endocrine findings, testosterone-to-cortisol ratios declined in non-infected players. Metabolic, hematologic, and anthropometric parameters were mostly stable, whereas hemoglobin exhibited a significant pooled increase. Musculoskeletal and gastrointestinal data were insufficient for broad conclusions. Moreover, meta-analytic estimates require cautious interpretation owing to few studies and very low certainty. Altogether, COVID-19 was associated with modest and mostly reversible effects, with structured home-based training potentially offsetting detraining. Rare cardiac abnormalities still warrant careful medical supervision.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The Australian Institute of Sport Sports Supplement Program, launched in 2000, promotes evidence-based, safe, and legal supplement use in Australian high-performance sports. It has evolved into a comprehensive framework in response to regulatory changes, rapid growth in supplement products, and widespread access to both information and misinformation. Founded on a “food first” philosophy, it recognises circumstances where supplements may offer unique advantages, including addressing nutrient deficiencies, providing support pre-, during and post-exercise, and supporting performance. Its principles were shaped to counter fragmented regulation, aggressive marketing, and athletes' reliance on non-expert information sources. Central to the framework is a dynamic ABCD classification system, categorising supplements according to the strength of scientific evidence for their effectiveness, safety, and anti-doping risk. Key initiatives include web-based education resources, strategic supplement provision, applied research, and robust governance—especially batch testing and integrity processes—to reduce anti-doping rule violations. The framework now serves as a benchmark for national and international sporting bodies and has driven a cultural shift that places sports dietitians at the forefront of supplement guidance and enhances collaboration across performance support and medicine staff. Future priorities include deeper digital integration, adequate resourcing to remain contemporary, and broader athlete and stakeholder engagement to maintain rigorous, evidence-informed standards.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study described the epidemiology of elbow medial ulnar collateral ligament injuries in collegiate baseball players between the 2014 to 2015 and 2018 to 2019 academic years using National Collegiate Athletic Association Injury Surveillance Program data. Injury rate ratios and descriptive statistics were used to characterize the epidemiology of these injuries. The overall medial ulnar collateral ligament injury rate in National Collegiate Athletic Association baseball players between 2015 and 2019 was 0.95/10,000 athletic exposures. Medial ulnar collateral ligament injury rates rose annually from 2015 to 2019. The medial ulnar collateral ligament injury rate was statistically significantly higher in competition (1.36/10,000 athletic exposures) than practice (0.61/10,000 athletic exposures; injury rate ratio: 2.22; confidence interval: 1.27–3.88). Pitchers accounted for 83.3% of injured players. Forty-three percent of medial ulnar collateral ligament injuries required athletes to miss the remainder of the season, and 18.5% of medial ulnar collateral ligament injuries required surgical intervention. In conclusion, the rate of medial ulnar collateral ligament injuries in collegiate baseball players increased steadily each year from 2015 to 2019. Medial ulnar collateral ligament injuries occur at a significantly higher rate during competition compared to practice, and pitchers account for the greatest number of medial ulnar collateral ligament injuries among college baseball players.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Sport has traditionally been organised into male and female categories, but the increasing visibility of transgender athletes has prompted sporting organisations worldwide to develop relevant eligibility regulations. These policies range from hormone thresholds and open categories to puberty-based exclusions and blanket bans, yet they are rarely based on direct scientific evidence. This review aims to examine the historical evolution of transgender inclusion in sport, map current international regulations and evaluate the evidence underpinning these approaches. First, we outline the temporal evolution of eligibility frameworks. We then review the roles of sex hormones in performance-relevant systems and assess how these mechanisms may result in physiological changes in transgender athletes receiving testosterone- or estradiol-based gender affirming hormone therapy. Studies demonstrate that gender affirming hormone therapy induces physiological changes that may translate to measures of physical fitness, but are limited by cross-sectional designs, small cohorts, short follow-up periods, heterogeneous treatment regimens and outcome measures that are rarely sport specific. Therefore, the certainty of this evidence remains low, and existing data are insufficient to support uniform policies across all disciplines. We therefore recommend that fairness and safety considerations should not be resolved through biology alone and propose a structured, sport-specific framework for policy development and revision under uncertainty.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Monitoring internal physiological responses in elite soccer players remains challenging due to the limitations of subjective scales and nonspecific biomarkers. This study examined whether leukocyte morphology and endothelial stress markers respond to acute exercise and a 6-week preseason training program in elite soccer players and explored their potential utility for objective athlete monitoring. Twenty-two male outfield players were assessed at baseline (48 h pre–preseason), immediately after a maximal Yo–Yo intermittent running test, and 72 hours after the preseason period. Leukocyte volume, conductivity, and scatter, factor VIII, von Willebrand factor, inflammatory, and metabolic markers were measured. Principal component analysis and K-means clustering explored morphological response patterns. Acute exercise increased white blood cells (+29%), neutrophils (+47%), platelets (+15%), factor VIII (+102%), and von Willebrand factor (+80%; all p<0.003) without changes in volume, conductivity, and scatter parameters. After 6 weeks, the lymphocyte volume, conductivity, and scatter and neutrophil conductivity and scatter decreased significantly (all p<0.0042), whereas leukocyte counts remained unchanged. Cluster analysis identified two morphological response patterns. These findings indicate phase-specific leukocyte morphological and endothelial responses to acute and chronic training and suggest that automated hematology markers may detect subclinical physiological adaptations not captured by conventional indices.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The purpose of this study was to investigate preseason side-to-side differences between injured and non-injured legs in range of motion and passive torque, as well as comparisons between injured and non-injured groups, in collegiate soccer players who did and did not sustain hamstring strain injuries. Collegiate male soccer players (n=108) participated in this study. Range of motion (straight leg raising and passive knee extension) and passive torque were assessed at the beginning of the preseason. Hamstring strain injuries were defined as any acute posterior thigh pain that occurred in non-contact situations, resulting in the immediate cessation of exercise. Eighty-four players were included in the analysis, and 10 players suffered hamstring strain injuries. There were no significant side-to-side differences or between-group differences in the range of motion. There was a significant difference in the passive torque between injured and non-injured legs (p=0.04). There was no significant difference in the range of motion asymmetries between groups, whereas passive torque asymmetry was significantly greater in the injured group (p<0.01). The results suggested that preseason passive torque asymmetry may be a potential risk factor for hamstring strain injury in collegiate male soccer players.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Adequate endurance capacity is crucial for training quality, recovery, and long-term development of gymnasts. The shuttle run test is a valid and efficient field test for estimating aerobic capacity (i.e., maximum oxygen uptake) in children and adolescents. Adapted to the indoor restrictions of an artistic gymnastics floor, a feasible 12 m shuttle run test was examined for its validity and absolute and relative reliability. Young gymnasts (n = 69; age: 12.3±1.6 y; body mass index: 17.6±2.0 kg*m−2; training experience: 6.6±2.3 y), competing at trained and highly trained levels in artistic, trampoline, and rhythmic gymnastics, initially performed a laboratory treadmill test and two further 12 m shuttle run tests on a gymnastics floor. Oxygen uptake during laboratory and on-floor testing was assessed until objective exhaustion criteria were reached. The 12 m shuttle run test demonstrated good validity for relative maximal oxygen uptake (intraclass correlation coefficient2,1: 0.82 and 95% confidence interval: 0.72–0.88) with moderate limits of agreement (95% confidence interval: –10.7–9.2 mL*kg−1*min−1) between the treadmill and the 12 m shuttle run test. The test–retest reliability of the 12 m shuttle run test for relative maximal oxygen uptake was good (intraclass correlation coefficient2,1: 0.79, 95% confidence interval: 0.64–0.89). The on-floor 12 m shuttle run test serves as a sufficiently valid and reliable endurance testing tool, enabling the regular assessment with a potential classification of aerobic capacity requirements.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Circulating irisin, a myokine linked to exercise-induced metabolic adaptation, may respond to exercise intensity and serve as a marker of training status. This study assessed intensity-dependent acute irisin responses in master athletes and recreationally trained men, baseline irisin associations with maximal oxygen uptake and body fat, and fibronectin type III domain–containing protein 5-related pathways using bioinformatics. Master endurance athletes (n=11; 49.9±5.8 y) and recreationally trained men (n=10; 49.9±7.2 y) completed two running sessions (moderate and severe), and plasma irisin was measured at rest and 15- and 120-minutes post-exercise. Exercise intensity significantly modulated acute irisin responses (time×intensity, p=0.006), with greater and earlier increases after severe exercise. Master endurance athletes exhibited consistently higher irisin than recreationally trained men (p<0.001), with intensity effects in both groups; baseline irisin was inversely associated with body fat (p=0.018) and positively with maximal oxygen uptake (p<0.001). Complementary RNA-seq analyses showed an age-related decline in skeletal muscle fibronectin type III domain–containing protein 5 expression, preserved by long-term endurance training via upregulated mitochondrial and energy metabolism pathways. Together, these findings indicate that exercise intensity and lifelong training modulate irisin regulation, supporting its use as a biomarker of aerobic fitness, metabolic adaptation, and healthy aging.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Equestrian sport is a major component of German athletics, with broad recreational participation and a strong competitive sector. In 2019, about 2.32 million people identified as active riders, and more than 60,000 competitional licences were issued in 2021, reflecting substantial competitive engagement across the Olympic disciplines and national performance levels. Hip pain is a frequent and clinically relevant complaint among athletes and can stem from structural, degenerative, or overuse-related causes. In riding, the hip joint is crucial for transmitting forces and coordinating rider–horse interaction. Fine adjustments in tension and release at the hip allow riders to follow and influence the horse’s movement; pain can therefore disrupt key control mechanisms. Studies consistently show a notable burden of musculoskeletal symptoms among equestrians. Hip pain affects 8–19% of riders and is associated with impaired pelvic stability, reduced lower limb control, and performance limitations. Chronic symptoms frequently relate to previous injuries, and older riders report persistent discomfort, likely due to cumulative mechanical loading. This study aims to determine the prevalence and characteristics of hip problems in competitive German equestrians and identify relevant risk and protective factors.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study examined whether load–velocity relationship variables are sensitive indicators of maximal dynamic strength changes across introductory, overload, and taper microcycles. Twenty resistance-trained men completed a 3-week back squat and bench press program. One-repetition maximum and the two-point load–velocity relationship (20 kg and ~85% one-repetition maximum) were assessed before the introductory microcycle and after each microcycle. The results showed that (i) one-repetition maximum, area under the load–velocity relationship line (A line), and velocity–axis intercept (v 0) derived from peak velocity generally increased after the taper microcycle compared to earlier post-microcycle assessments (p≤0.046, differences=2.3–7.8%); (ii) the overload (coefficient of variation of individual response=5.1%) and taper (3.8%) microcycles exhibited greater variability compared with the introductory microcycle (2.0%). Among the monitored variables, variability was lowest for v 0 (0%), followed by one-repetition maximum and L 0 (4.1%), and highest for A line (5.3%); and (iii) A line derived from mean velocity was the only variable that maintained a significant association with changes in one-repetition maximum across exercises and microcycles (r=0.648–0.765, p≤0.003). These findings indicate that while short mesocycles elicit substantial inter-individual variability in adaptations, A line derived from mean velocity offers a practical, fatigue-free method to monitor meaningful maximal strength changes throughout a training cycle.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The aim of this study was to analyze, among lean adolescents, the changes in lipids associated with sports participation and the role of time spent in vigorous sports participation. Lean adolescents of both sexes were followed for 12 months (121 boys and 51 girls [aged 11–17 y]). Lipids were the dependent variables (total cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol, triacylglycerol and the atherogenic index of plasma). Adolescents were divided according to sports participation (engaged and not engaged), with sports participation intensity assessed by heart rate during sports. Multivariate models were adjusted by ethnicity, biological maturation, body fat, lean soft tissue, insulin resistance, and inflammation. The atherogenic index of plasma changed in favor of boys (engaged: −0.021 [95% confidence interval: −0.060 to 0.019] versus not engaged: 0.117 [95% confidence interval: 0.028 to 0.207]) and girls engaged in sports (engaged: −0.062 [95% confidence interval: −0.102 to −0.022] versus not engaged: 0.098 [95% confidence interval: −0.018 to 0.214]). The main determinants of changes in the atherogenic index of plasma among boys were changes in lean soft tissue (r=−0.415 and p=0.050) and vigorous physical activity among girls (r=−0.291 and p=0.012). In summary, sports participation was associated with improvements in lipid profile among lean adolescents.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This systematic review and network meta-analysis compared the effectiveness of five flexibility-enhancing interventions—static stretching, dynamic stretching, ballistic stretching, proprioceptive neuromuscular facilitation, and foam rolling—on ankle dorsiflexion range of motion in physically active healthy adults. A comprehensive search of multiple databases was conducted up to August 4, 2025. This review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and was registered in prospectively registered in the International Prospective Register of Systematic Reviews. Effect sizes were synthesized using a random-effects network meta-analysis, and intervention rankings were based on the surface under the cumulative ranking curve. Forty-one randomized controlled trials (n=1,670) were included. For the passive range of motion, proprioceptive neuromuscular facilitation (surface under the cumulative ranking curve: 76.8%) and foam rolling (67.8%) were the most effective overall. In long-term protocols (>1 mo), both proprioceptive neuromuscular facilitation (standardized mean difference 1.04 [0.64–1.44]) and foam rolling (standardized mean difference 1.03 [0.53–1.53]) remained superior to controls. For active range of motion, foam rolling ranked the highest (surface under the cumulative ranking curve: 87.2%) and demonstrated the largest short-term improvement, while static stretching showed the most favorable long-term maintenance (surface under the cumulative ranking curve: 72.4%). No intervention-related adverse events were reported. Proprioceptive neuromuscular facilitation and foam rolling are optimal for long-term flexibility enhancement, whereas foam rolling is recommended for short-term, pre-exercise movement preparation. Static stretching may support sustained active range of motion across extended training periods. Intervention selection should align with specific performance goals and training timelines.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Cardiovascular diseases remain the leading cause of death worldwide. Above-normal blood pressure is the primary modifiable risk factor for cardiovascular diseases and rates of blood pressure control remain suboptimal. Aerobic and resistance exercise are recommended lifestyle interventions for lowering blood pressure; however, adherence to exercise guidelines is low, contributing to poor rates of blood pressure control. Thus, alternative forms of physical activity that lower blood pressure and promote adherence are needed. This review examines isometric exercise, the Weekend Warrior physical activity pattern, and heat therapy as strategies for blood pressure lowering. Randomized controlled trials support isometric exercise for lowering blood pressure; however, the mechanisms of action require further investigation. The Weekend Warrior physical activity pattern, i.e., concentrating physical activity in 1–2 d/wk, is associated with lower rates of hypertension in cohort studies, but clinical trials are lacking. Cohort studies also support that regular sauna use is associated with lower rates of cardiovascular diseases. Small clinical trials also suggest that heat therapy can lower blood pressure; however, study designs are heterogeneous and the results are mixed. Overall, isometric exercise, the Weekend Warrior physical activity pattern, and heat therapy represent potential lifestyle approaches for lowering blood pressure and reducing cardiovascular disease risk.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Integrating proprioceptive and neuromuscular exercises into the FIFA 11+  Kids program may enhance motor performance and postural stability in youth athletes. This study aimed to determine the effects of a 12-week combined FIFA 11+  Kids and proprioceptive–neuromuscular training program (three sessions/wk) compared with regular standard soccer training on physical and postural performance in young male soccer players aged 12–13 years. Forty players (aged 12.19±0.59 years) were randomly assigned to an experimental group (n=20) or control group (n=20). Pre- and post-tests included anthropometry, linear sprints (5–10–20 m), vertical jumps (countermovement jump and squat jump), agility, Y-Balance, and stabilometric assessment (eyes open/closed). In the experimental group, body fat showed a non-significant downward trend (−2.93%; p=0.081), while leg muscle volume significantly increased (+5.53%; group×time: p=0.007; η p 2=0.183) alongside fat-free-mass (+2.41%; p=0.015). Sprint performance improved significantly at 5 m (5.16%; p=0.004; η p 2=0.206), 10 m (4.75%; p=0.008; η p 2=0.270), and 20 m (3.28%; p=0.019). Countermovement jump and squat jump also improved (7.63–14.97%; p=0.046 and p=0.002, respectively). Y-Balance scores and postural stability improved, particularly unipodal mediolateral sway (−35.19%; p=0.001; η p 2=0.224). Conversely, the control group showed no significant changes across anthropometric, performance, balance, or stabilometric parameters. The combined program effectively enhanced athletic performance, body composition, and postural control, strongly supporting its systematic implementation within youth soccer training programs.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Clarifying whether osteochondral lesions of the talus are associated with coronal plane ankle and hindfoot alignment abnormalities is critical for guiding surgical decisions such as supramalleolar or calcaneal osteotomy. This retrospective case series included 142 consecutive patients with osteochondral lesions treated between August 2014 and April 2019, with 111 patients met the inclusion and exclusion criteria and were enrolled finally. Patient data were carefully extracted and cross-checked, and the lesion location was determined via computed tomography or magnetic resonance imaging, grouping patients into 91 medial and 20 lateral cases. Standard weight-bearing radiographs were used to measure the tibial anterior surface angle, tibial axis–medial malleolus angle, tibio-talar angle, tibial lateral surface angle, hindfoot alignment angle, and lesion area. Inter-rater reliability assessed by intraclass correlation coefficients (≥ 0.85) showed excellent agreement. The medial group had a significantly older mean age (48.32 vs. 30.25 y, p < 0.01), greater hindfoot varus, larger tibial axis–medial malleolus angle, and smaller lesion area (p < 0.05), while no significant differences were found in the tibial anterior surface angle, tibio-talar angle, or tibial lateral surface angle. These findings indicate that medial osteochondral lesions of the talus correlate with hindfoot varus, emphasizing the need to assess and adjust alignment during clinical treatment.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study aimed to compare the effects of two bench press training programs differing in velocity loss modulation (stable vs. progressive) on strength and hypertrophic adaptations. Twenty-four resistance-trained men were randomly assigned to a stable velocity loss group or a progressive velocity loss group. Subjects trained the bench press for 8 weeks, 15 sessions, performing three sets per session at a 65–75% one-repetition maximum. The stable velocity loss group trained with a constant 25% velocity loss, whereas the progressive velocity loss group followed a progressive strategy (0-12.5-25-37.5-50% velocity loss). Assessments conducted before and after training included pectoralis major cross-sectional area, a progressive loading test, and the maximum number of repetitions in bench press. No significant differences in velocity loss between groups were observed during the training program (~26%). A significant main “time” effect was observed for all variables, with no significant group × time interactions. Only the progressive velocity loss group obtained significant increases in cross-sectional area (effect size=0.31), while only the stable velocity loss group significantly improved maximal unloaded velocity (effect size=0.80). Both stable and progressive velocity loss programming were effective at improving strength performance in bench press. However, stable velocity loss strategies may be preferable for athletes prioritizing high-velocity performance, whereas progressive velocity loss approaches may be more advantageous for hypertrophy-oriented athletes.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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To investigate the effects of descent from moderate altitude combined with exposure to high ambient temperatures on plasma volume, a repeated measures design was used in young male cyclists (n=10). The cyclists (age: 18.2±1.2 y and maximal oxygen uptake​:​​​​​​ 62.0±4.1 mL/kg/min), who lived at an altitude of 2,600 m, trained at a lower altitude (450 m) for 7 days. Hematological variables were measured prior to descent, at low altitude, and 1 day after returning to 2,600 m. Hemoglobin mass was measured before descent and used for the indirect calculation of plasma volume. Hemoglobin concentration decreased from 17.1±0.7 g/dL to 15.9±0.6 by day 1 and to 15.4±0.3 g/dL by day 5 (both p<0.001) and then increased to 16.5±0.7 g/dL the day after returning to the initial altitude. Plasma volume increased from 2,946±463 mL by 12.9±6.6% on day 1, reached a maximum of 16.2±9.7% on day 5 (both p<0.01), and decreased again to+7.4±9.5% after returning to the altitude. The change from moderate to low altitude leads to a rapid increase in plasma volume, which can be expected to affect performance by reducing oxygen transport capacity and increasing maximal cardiac output. Additionally, the athlete’s biological passport may be affected erroneously.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The present study aimed to assess the reliability, responsiveness, and age-related and competitive level differences of a 25-m change of direction maneuver (V-cut test) in football players. Two-hundred and eighty-nine male football players performed the V-cut test. Thirty-four players underwent the test on two occasions, separated by 5–7 days, to assess test–retest reliability. Eighty-six young players performed the V-cut test three times, separated by 12 weeks, to analyze responsiveness. Finally, 89 young players of different ages (U-15 to U-20) and 80 adult players of different competitive levels performed the V-cut test several times throughout the season to examine between-group differences. Reliability analysis showed a high intraclass correlation coefficient of 0.94 and a low coefficient of variation of 0.8%. The responsiveness was dependent on maturity status, showing a positive response in pre-peak height velocity (short-term p<0.05) or post-peak height velocity (short- and long-term p<0.05) players, although the peak height velocity group did not exceed the minimal detectable change. Age-related (effect size [ES]: 0.93–5.68) and competitive-level difference (ES: 0.57–1.96) analyses reported better V-cut test performance as age and competitive-level increased in football players. The V-cut test is reliable for assessing change of direction ability and can be used to monitor change of direction ability depending on maturity, allowing it to differentiate between players of different ages and levels.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study investigated whether acutely consuming a large dose of a highly acidic beverage (orange juice) affects blood pH, muscle oxygenation or exercise performance in young active men. Thirteen participants completed two experimental phases. In Phase A, subjects ingested either orange juice with added sodium bicarbonate (pH 6.72±0.32; placebo) or orange juice (pH 3.50±0.99), randomly assigned. Blood pH and muscle oxygenation were monitored over 40 minutes following the ingestion of both beverages to identify any beverage-induced changed in blood pH and muscle oxygenation to guide sampling times for Phase B. In Phase B, participants consumed the same beverage as in Phase A, followed by assessments of anaerobic (Wingate test) and aerobic (peak oxygen consumption) performances, along with continuous muscle oxygenation monitoring. Results showed no significant differences (p>0.05) between treatments in blood pH, aerobic or anaerobic performance, or muscle oxygenation parameters. The acute ingestion of a highly acidic beverage like orange juice does not disrupt acid–base regulatory mechanisms or impair physiological or performance outcomes in healthy active men. These findings highlight the robustness of the body’s acid–base regulatory mechanisms and offer direct empirical evidence countering publicly circulated claims that normal dietary acidity impairs physiological function or exercise performance.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Foot muscle strength influences jumping performance, but adaptation differences between barefoot and shod training remain unclear. This study compared the effects of an 8-week training program performed barefoot (BARE), shod (SHOD), or without training (CON). Healthy habitually SHOD non-athlete adults (age: 39.0±10.6 y; height: 1.61±0.08 m; body mass: 61.5±9.8 kg) were assigned to BARE (n=19), SHOD (n=17), or CON (n=17) groups. Participants in the training groups performed 60-minute sessions twice weekly. Toe flexor strength, foot arch height, and jump performance were assessed at baseline and weeks 2, 4, 6, and 8. In the BARE group, toe flexor strength increased by 8.3% at week 2 (p≤0.05) and continued to improve through weeks 4–8 (p≤0.01, effect size=1.17), whereas gains in the SHOD group appeared at week 4 and were limited to baseline comparisons. Vertical jump height improved similarly across groups, whereas standing broad jump distance improved in the BARE group after 8 weeks (p≤0.01) and was greater than that in the CON group (p≤0.01, effect size=1.12). These findings suggest that identical barefoot training induces earlier and progressive improvements in foot muscle strength and may contribute to improved forward jump performance.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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This study aimed to (1) identify acute changes in supraspinatus and biceps longus tendon thickness after pitching and (2) determine the relationship between changes in tendon thickness and changes in glenohumeral range of motion after pitching. Fourteen healthy men with at least 5 years of baseball experience as baseball players performed 100 full-effort fast ball pitches. Tendon thicknesses and the glenohumeral internal rotation range of motion were measured before, immediately after, and 24 hours after pitching. One-way repeated-measures analysis of variance or the Friedman test with Bonferroni post hoc comparisons was performed to compare changes in tendon thicknesses and glenohumeral range of motion due to repetitive pitching and to identify the relationships between changes in tendon thicknesses and in glenohumeral internal rotation range of motion. The supraspinatus and biceps longus tendon thicknesses increased immediately (p<0.001) and 24 hours after pitching (supraspinatus: p=0.024 and biceps longus: p<0.001). The glenohumeral internal rotation range of motion decreased immediately after pitching (p<0.001) but not at 24 hours (p=0.086). The decreased glenohumeral internal rotation range of motion was associated with increased supraspinatus tendon thickness immediately after pitching (r=− 0.77 and p=0.001). Our results suggest that it takes time for tendon swelling to improve in pitchers after high-velocity repetitive pitches.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Exercise-associated gastrointestinal symptoms stemming from exercise-induced gastrointestinal syndrome are a common feature of sports participation. Exercise-associated gastrointestinal symptoms have the potential to directly impair sports performance or could indicate something more sinister warranting medical attention. Managing the underlying pathophysiological pathways of exercise-induced gastrointestinal syndrome is key to reducing exercise-associated gastrointestinal symptoms in athletes during their sporting activities. Recent advancements in exercise gastroenterology have enhanced the understanding of pathophysiology, assessment methodologies, prevention and management strategies. The current narrative review aims to provide a professional practice guide for the identification, assessment, intervention, and monitoring of exercise-induced gastrointestinal syndrome and exercise-associated gastrointestinal symptoms. A referral pathway and a four-phase approach to athlete support have been proposed. The athlete support pathway components include initial clinical assessment, gastrointestinal assessment during exercise, implementation of evidenced-informed prevention or management strategies based on the gastrointestinal assessment during exercise data interpretation, and ongoing monitoring and adjustment in real-world settings. This structured approach has been shown to reduce exercise-associated gastrointestinal symptoms and potentially mitigate underlying medical risks arising from exercise-induced gastrointestinal syndrome.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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Lower extremity fractures are relatively common in winter sports. This retrospective descriptive study evaluated the demographics, injury mechanisms, and environmental factors associated with lower leg fractures (below the knee, excluding tibial plateau and fibular head fractures) among patients treated at a Colorado clinic during the 2012/13 to 2016/17 ski seasons. The chart review confirmed diagnoses and assessed associated factors. A total of 346 lower leg, ankle, and/or foot fractures were identified, representing 5.4% of all visits. The average patient age was 33.1 years (range 4–74), and 60.7% were men. Most injuries were ski-related (84.7%). The majority of fractures were sustained among skiers and snowboarders who self-identified as a beginner or an intermediate skill level (64.8%), on easy or intermediate runs (64.9%). The most common injuries were complete tibia/fibula fractures (36.4%), isolated tibia fractures (28.3%), and lateral malleolus fractures (26.9%). Of the complete tibia/fibula fractures, 57.0% were “boot-top” fractures. Danis–Weber B was the most frequent type of lateral malleolus fracture (73.6%). Only 12 foot fractures were recorded. In conclusion, lower leg fractures were more common in skiers than snowboarders and in men than women. Most fractures occurred on mild-to-moderate runs, with lower risk in older individuals. Tibia/fibula fractures were most common, followed by lateral malleolus fractures.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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The interference effect associated with concurrent training has been widely debated. A recent model suggests that including sprint interval training as the endurance component may attenuate this effect. However, studies examining the impact of sprint interval training-based concurrent training on neuromuscular and cardiorespiratory adaptations are limited. This systematic review with meta-analysis evaluated the effects of concurrent training programs including sprint interval training on strength, hypertrophy, maximum oxygen consumption, and sprint performance. Searches were conducted in PubMed, Embase, and SPORTDiscus, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Randomized controlled trials in healthy adults (≥18 y) comparing sprint interval training-based concurrent training with resistance training alone, including at least six supervised sessions over 2 weeks, were eligible. Nine studies (177 participants) met the inclusion criteria. Pooled analyses showed no significant differences between sprint interval training combined with resistance training and resistance training alone for lower-body strength (standardized mean difference=0.01; p = 0.94), upper-body strength (standardized mean difference=− 0.06; p = 0.83), jump performance (standardized mean difference=0.11; p = 0.11), or sprint performance (standardized mean difference=− 0.01; p = 0.95). However, sprint interval training combined with resistance training significantly improved maximum oxygen consumption compared with resistance training alone (standardized mean difference=0.78; p = 0.001). Sensitivity analysis revealed greater jump gains with short sprint protocols (≤10 s; standardized mean difference=0.41; p = 0.025). These findings indicate that introducing sprint interval training into concurrent training enhances cardiorespiratory fitness without compromising strength or power and may potentiate jump performance when short sprints are used.
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Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany

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