Search Results (1,117)

In this study, we examined the thermal response of the vastus lateralis muscle using a skin calorimeter designed for localized measurements. Five healthy young male participants (20–23 years old) performed an incremental test on a cycle ergometer at 20 W·min⁻¹ until exhaustion. The calorimeter’s thermostat was maintained at 30 °C. Ambient temperature was 23 ± 1 °C, and relative humidity ranged from 55% to 60%. The measured heat flow was modeled using functions relating mechanical power output to the thermal response. The model included the exercise phase, recovery, and sweat evaporation. The proposed model accurately reproduced the experimental data and supported a physiological interpretation of the main thermal effects. Two major contributions were identified and physiologically interpreted as muscle warming due to increased metabolic activity and a cooling effect likely linked to changes in blood perfusion. For an area of 2 × 2 cm² and an incremental exercise of 20 W·min⁻¹, the following values were obtained: (1) a resting heat loss of 150 ± 20 mW; (2) an exponential increase due to exercise of 0.4 ± 0.1 mW·W⁻¹, with a time constant of 1.0 ± 0.3 min; and (3) a negative blood-flow contribution described by a function that, in the steady state, has a amplitude of −20 ± 9 mW. Since only five participants were included, correlations with anthropometric variables were treated as exploratory consistency checks. These results demonstrate the usefulness of the calorimeter for decomposing and quantifying muscle thermal dynamics during exercise. Full article

Background: Injuries are a major concern in professional football because they may reduce player availability and affect team performance. Injury risk may vary across different phases of the season in relation to changes in training and competition demands, recovery, and cumulative workload. Objectives: To describe the epidemiology of injuries in a professional football team over three consecutive seasons and to evaluate seasonal variations in injury characteristics and injury-related time-loss. Methods: This retrospective study analyzed 260 time-loss injuries sustained by 78 of 96 registered male first-team players (mean age 27.0 ± 4.5 years) from a professional football club in Türkiye over three consecutive seasons (2022–2023 to 2024–2025). Total team exposure was 33,609 player-hours (2409 match player-hours and 31,200 training player-hours). Injuries were classified according to injury setting, seasonal period, anatomical location, injury type, and injury-related time-loss. Exploratory generalized estimating equations (GEE) analysis accounted for repeated injuries within players. Results: A total of 260 injuries were recorded; 62.3% occurred during training and 37.7% during matches. The overall injury incidence was 7.7 per 1000 player-hours (95% CI, 6.8–8.7), with rates of 40.7 per 1000 match player-hours (95% CI, 33.0–49.6) and 5.2 per 1000 training player-hours (95% CI, 4.4–6.1). The groin–thigh–lower-leg region (52.7%) and the thigh (25.4%) were the most frequently affected anatomical sites, while muscle injuries accounted for 43.5% of all injuries. Estimated injury incidence was highest during the mid- and late-season (9.29 and 9.12 per 1000 player-hours, respectively) and lowest during the preparation period (2.55 per 1000 player-hours). Exploratory GEE analysis showed significant differences in injury counts across seasonal periods (Wald χ² = 41.35, p < 0.001). Compared with the late season, injury incidence was lower during the preparation period (IRR 0.17, 95% CI 0.09–0.33; p < 0.001), whereas no significant differences were observed for the early or mid-season. Conclusions: Injury incidence was lowest during the preparation period and highest during the competitive season. Because exposure estimates were based on team-level rather than individual player-level data, these findings should be interpreted cautiously. Prospective multicentre studies with individual exposure data are needed. Full article

Background/Objectives: Shoulder pain in tennis players is usually interpreted from a local shoulder perspective, although kinetic-chain and trunk-control factors may also be relevant. The diaphragm contributes to breathing and trunk stabilization, but diaphragm-related measures have received limited attention in tennis players with shoulder pain. This study compared inspiratory muscle strength, diaphragm thickness, and diaphragm thickening fraction between tennis players with and without non-specific shoulder pain. Methods: This observational cross-sectional study included 64 tennis players: 32 with non-specific shoulder pain and 32 asymptomatic controls. Maximum inspiratory pressure (MIP), bilateral diaphragm thickness during relaxed inspiration and expiration, and diaphragm thickening fraction were assessed. Between-group differences were analyzed. Results: Tennis players with non-specific shoulder pain showed lower MIP than controls (p = 0.002). Diaphragm thickness during relaxed inspiration was lower in symptomatic players on the left (false discovery rate (FDR)-adjusted p = 0.033) and right sides (FDR-adjusted p = 0.012), and diaphragm thickening fraction was also lower bilaterally (left: FDR-adjusted p = 0.036; right: FDR-adjusted p = 0.039). Conclusions: Tennis players with non-specific shoulder pain showed lower inspiratory muscle strength, lower bilateral diaphragm thickness during relaxed inspiration, and lower bilateral diaphragm thickening fraction than asymptomatic players. These cross-sectional findings describe group-level differences but do not establish causality, diaphragm dysfunction, or clinical relevance. Full article

Background: Running-related injuries are a common issue among recreational runners and may affect training continuity and long-term participation. However, injury-associated factors remain unclear due to methodological heterogeneity and reliance on self-reported data. Objective: This study aims to determine the prevalence and anatomical distribution of running-related injuries and their association with physiological characteristics and weekly running volume in recreational runners. Methods: A cross-sectional study was conducted with 98 recreational runners (57 men and 41 women). Women were aged 41.54 ± 9.14 years, weighed 59.55 ± 5.89 kg, and had a maximal oxygen uptake ($\stackrel{.}{\mathrm{V}}$O₂max) of 43.24 ± 4.86 mL·kg⁻¹·min⁻¹, whereas men were aged 40.16 ± 8.85 years, weighed 80.50 ± 12.89 kg, and had a $\stackrel{.}{\mathrm{V}}$O₂max of 47.73 ± 7.55 mL·kg⁻¹·min⁻¹. Running-related injuries during the previous 12 months were clinically confirmed. Sex, age, body composition, $\stackrel{.}{\mathrm{V}}$O₂max, resting heart rate, and weekly training volume were analyzed using independent t-tests and multivariable logistic regression. Results: Running-related injury prevalence was 43.9% (women: 56.1%; men: 35.1%), with a significant association between sex and injury occurrence (Fisher’s exact test, p = 0.043). The knee was the most frequently affected anatomical region, followed by the leg and ankle/Achilles regions. Iliotibial band syndrome was the most common diagnosis, followed by calf muscle injury, Achilles tendinopathy, plantar fasciopathy, ankle sprain, and hip labral tear. None of the demographic or physiological variables investigated, including weekly running volume, were independently associated with injury occurrence, and the model explained only a small proportion of the variability in injury occurrence. Conclusions: Running-related injuries were frequent among recreational runners, with knee-related injuries representing the most common anatomical pattern and iliotibial band syndrome being the predominant diagnosis. Although female runners presented a higher injury prevalence, the multifactorial nature of running-related injuries was reinforced, as the investigated demographic and physiological characteristics, along with weekly running volume, showed limited explanatory capacity for injury occurrence. Full article

Background: Neurodynamic techniques are commonly used to improve neural mobility and musculoskeletal function, but their effects on muscle mechanical properties remain unclear. This study investigated the acute effects of femoral nerve slider, femoral nerve tensioner, and static stretching interventions on the rectus femoris and vastus medialis muscles. Methods: Thirty healthy adults (18–35 years) were non-randomly allocated using a predetermined alternating sequence to a femoral nerve slider (n = 10), femoral nerve tensioner (n = 10), or static stretching group (n = 10). No sham or no-intervention control group was included. Muscle mechanical properties were assessed before and immediately after the intervention using the MyotonPRO (Myoton AS, Tallinn, Estonia). Outcomes included muscle tone, stiffness, logarithmic decrement, relaxation time, and creep. A three-way mixed repeated-measures ANOVA was performed. Results: No statistically significant differences in pre–post changes were detected among the three intervention groups for any of the examined mechanical parameters. Significant main effects of time were found for stiffness (p = 0.026) and creep (p = 0.005), indicating overall reductions from pre- to post-assessment. Significant time × muscle interactions were identified for relaxation time (p = 0.029) and creep (p = 0.002), indicating different temporal patterns between the rectus femoris and vastus medialis. Following Holm adjustment of the follow-up comparisons, the pre–post reduction in the vastus medialis remained statistically significant for creep but not for relaxation time. The rectus femoris demonstrated greater stiffness and logarithmic decrement values, whereas the vastus medialis exhibited greater relaxation time values. Conclusions: No statistically significant differences in immediate pre–post changes in quadriceps muscle mechanical properties were detected among the femoral nerve slider, femoral nerve tensioner, and static stretching groups. Temporal and muscle-specific patterns were observed for selected mechanical parameters; however, these findings should not be interpreted as evidence of equivalence between the interventions. Full article

Biodegradable magnesium (Mg)-based implants represent a paradigm shift in orthopedic biomaterials, offering temporary mechanical support, inherent osteogenic bioactivity, and elimination of hardware removal surgery. These properties are particularly attractive for sports orthopedic applications, including anterior cruciate ligament (ACL) reconstruction, rotator cuff repair, meniscal fixation, and osteochondral fragment refixation, where young, active patients demand rapid return to function and where permanent metallic hardware poses long-term risks of stress shielding, imaging artifact, and reoperation. Despite extensive preclinical evidence demonstrating that Mg-based interference screws promote fibrocartilaginous enthesis regeneration, attenuate peri-tunnel bone loss, and achieve biomechanical fixation comparable to titanium, no human clinical trial has yet evaluated Mg fixation devices for soft-tissue reconstruction in sports medicine. Meanwhile, clinical fracture fixation data from over 468 patients across multiple trials and a meta-analysis confirm complication rates equivalent to those of titanium. This narrative review synthesizes the current evidence on Mg alloy design, surface engineering strategies, preclinical sports medicine applications, clinical translation in fracture fixation, imaging compatibility, and the remaining barriers to clinical adoption in sports orthopedic surgery. By mapping the translational gap between promising animal data and the absence of clinical sports medicine trials, this review aims to guide future research priorities and accelerate the pathway toward clinical application of Mg-based devices in sports orthopedics. Full article

Erythropoiesis-targeted doping remains a major challenge for sports medicine because pharmacological and genetic manipulation of erythropoiesis can improve oxygen transport and endurance performance while increasing the risk of serious cardiovascular complications. Erythropoiesis-targeting strategies extend beyond recombinant erythropoietin (EPO) to include hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs), modified erythropoietin receptor (EPOR) agonists, transforming growth factor beta (TGF-β) signaling inhibitors, cytoprotective EPO derivatives, and gene- or cell-based approaches, and require complementary detection strategies based on direct analytical methods and the Athlete Biological Passport (ABP). Although they may enhance oxygen delivery and endurance performance, excessive stimulation of erythropoiesis may increase blood viscosity, impair vascular function, and elevate the risk of hypertension, thromboembolic complications, and other cardiovascular (CV) events. Erythropoiesis-targeted doping has evolved beyond recombinant EPO into a diverse group of pharmacological and genetic strategies that require increasingly sophisticated detection approaches. A thorough understanding of their molecular mechanisms and cardiovascular consequences is essential for improving anti-doping surveillance and protecting athlete health. This review summarizes current erythropoiesis-targeting agents, their mechanisms of action, detection strategies, cardiovascular risks, and implications for anti-doping practice. Full article

Background/Objectives: The physiological adaptations required to sustain elite football performance are influenced by both genetic background and dynamic biochemical responses, although their interaction across a full competitive season remains insufficiently characterized. This study aimed to examine the association between polygenic profiles and longitudinal biochemical adaptations in professional football players. Methods: Forty male professional football players competing in the Spanish league were monitored across two consecutive seasons. Blood samples were collected at six time points representing different phases of the competitive cycle. Biomarkers related to muscle metabolism, iron status, and hepatic function were analyzed. Polygenic profiles were calculated using Total Genotype Scores (TGS) for muscle performance, hepatic resilience, and metabolic efficiency. Associations were initially explored using Pearson correlations and subsequently evaluated using linear mixed-effects models accounting for repeated measurements within subjects. Results: Exploratory correlation analyses identified several associations between polygenic profiles and biochemical markers. Muscle performance TGS was inversely associated with serum iron (r = −0.36, p = 0.017) and positively associated with CK (r = 0.32, p = 0.041), Hb (r = 0.29, p = 0.046), and Hct (r = 0.33, p = 0.024). Hepatic resilience TGS showed inverse associations with ALT (r = −0.39, p = 0.012), urea (r = −0.51, p = 0.011), and BUN (r = −0.51, p = 0.011). Metabolic efficiency TGS was negatively associated with AST (r = −0.43, p = 0.044), ALT (r = −0.33, p = 0.025), and GGT across multiple time points (p = 0.001–0.013). However, although several nominal associations emerged in linear mixed-effects models accounting for repeated measurements, none remained statistically significant after false discovery rate correction. These findings should therefore be interpreted as exploratory and hypothesis-generating. Conclusions: Polygenic profiles may be associated with inter-individual variability in biochemical adaptations throughout a competitive season. These findings suggest the integration of genomic and biochemical data in precision athlete monitoring, while highlighting causal relationships and predictive applications require further investigation. Full article

Background: Sports-related musculoskeletal injuries, including tendon, ligament, muscle, and cartilage damage, often heal slowly and incompletely. Current treatments may not fully restore tissue function, necessitating regenerative therapies. Objective: This study was conducted to review the therapeutic potential of stem cell-derived extracellular vesicles (EVs) and conditioned medium (CM) as cell-free approaches to treating musculoskeletal injuries in sports medicine. Methods: A narrative review of preclinical and early clinical studies investigating the biological mechanisms and regenerative effects of mesenchymal stem/stromal cell (MSC)-derived EVs and CMs published between 2019 and 2026 was performed by searching Scopus, PubMed, Web of Science, and Google scholar. Results: EVs and CMs contain bioactive molecules, including microRNAs, cytokines, and growth factors, that modulate inflammation, promote tissue repair, enhance angiogenesis, and support extracellular matrix remodeling. Preclinical studies demonstrate improved healing of tendons, ligaments, muscles, and cartilage, while early clinical evidence suggests favorable safety and promising therapeutic outcomes. However, the variety of MSC sources, EV separation methods, characterization procedures, and treatment protocols present major challenges in determining the reliability and therapeutic efficacy of these therapies. Notably, the number of clinical studies on EV and CMs is still limited, and most of the available studies are in vitro studies. Conclusions: MSC-derived EVs and CMs represent promising cell-free regenerative therapies for sports-related musculoskeletal injuries. The available evidence, which demonstrates their ability to enhance healing while avoiding the challenges associated with cell-based therapies, highlights their translational potential. However, most of the studies that are now available are preclinical or early-stage clinical studies, and there is still a limited number of clinical trials. Further well-designed clinical studies are needed to establish standardized protocols and confirm long-term safety. Full article

Background/Objectives: Healthcare professionals have begun utilizing a wheelie task for balance assessment in para sport athletes. With recent advancements to incorporate dual-task exercises, the purpose of this study was to evaluate baseline wheelie performance during single and dual-task and measure 1-week and 45-day reliability in a sample of collegiate para sport athletes. Methods: Twenty-five (male n = 14, 56.0%) collegiate para sport athletes completed a wheelie assessment under single and dual-task conditions. Measures consisted of standardized biomechanical errors (e.g., front wheels touching ground, changing grip on wheel) as scored by a single clinician during eyes-open and eyes-closed positions. Assessments were repeated 7 ± 2 days and 45 ± 7 days later. Results: At baseline, there were no differences with dual-task exercise during eyes-open wheelie balancing (p = 0.096). No differences were observed from single to dual-task in the eyes-closed position (p = 0.154) at baseline, but there were significantly more errors during this position at both the 1-week (p = 0.005) and 45-day (p = 0.004) retest intervals. Fair to moderate correlations existed for both eyes-open and eyes-closed positions during single and dual task across 1-week (rs ≥ 0.49) and 45-day (rs ≥ 0.40) retest intervals. Conclusions: The incorporation of dual-task exercises during the eyes-closed wheelie position appears to increase the difficulty of balance compared to single-task, possibly making it a useful assessment to evaluate balance in para-athletes. There is fair to moderate correlation of the wheelie during single and dual tasks over time. Future research is needed on dual-task compensation post-injury. Full article

Background/Objectives: School-age athletes occupy a paradoxical position in the adolescent opioid crisis, combining health-oriented activity with elevated risk of sports-related injury and prescription opioid exposure. In response to the opioid epidemic, states enacted opioid prescribing limit laws (OPLLs) beginning in 2016–2017, yet whether these supply-side policies reached high-risk youth subgroups remains unclear. This study evaluated national temporal trends in prescription opioid misuse among U.S. high school students during the period of OPLL implementation and examined differences across athletic participation, concussion history, sex, grade, race/ethnicity, and substance-use profiles. Methods: Using four biennial waves of the Youth Risk Behavior Surveillance System with a consistent prescription pain-medicine measure (2017, 2019, 2021, and 2023; total N = 44,501), we conducted survey-weighted multivariable logistic regression models producing adjusted odds ratios (aORs) for lifetime prescription opioid misuse, controlling for survey year, sports participation, sex, grade, race/ethnicity, alcohol use, and other illicit drug use. Interaction and stratified models examined differences associated with sports participation, concussion history, demographic characteristics, and substance use. Results: Weighted prescription opioid misuse declined from 13.9% in 2017 to 12.0% in 2023, with a significant unadjusted linear decline per two-year survey wave (OR = 0.936; 95% CI: 0.879–0.997; p = 0.040). This overall trend was attenuated after adjustment (aOR = 0.967; 95% CI: 0.914–1.024; p = 0.248). Temporal patterns differed significantly across race/ethnicity, sex, grade, and selected substance-use groups. White and male students demonstrated significant adjusted linear declines, whereas Hispanic/Latino and female students remained flat. Black/African American students showed significant year-to-year variation, with elevated adjusted odds in 2019 and 2021 relative to 2017. Concussion history was independently associated with misuse among athletes (aOR = 1.645; 95% CI: 1.417–1.909; p < 0.001), with significant associations observed among White, Asian, Black/African American, and Hispanic/Latino athletes. The pooled concussion-by-race/ethnicity interaction, however, was not significant (p = 0.295). Conclusions: Although prescription opioid misuse declined descriptively between 2017 and 2023, adjusted analyses did not identify a significant overall national temporal change. Since subgroup patterns diverged, prevention planning and surveillance should be disaggregated by race/ethnicity and sex rather than guided by national totals, and groups whose misuse did not decline may require strategies extending beyond clinical prescribing controls. Full article

Background and Objectives: Rugby Union is associated with a high incidence of injuries. Although injury epidemiology has been extensively documented internationally, data from Portuguese rugby remain scarce despite the sport’s recent growth and increasing visibility. This study aimed to investigate the incidence, characteristics, and severity of time-loss match injuries, as well as their impact on match availability, in the top tier of Portuguese Rugby Union XV. Materials and Methods: A prospective cohort study was conducted during the 2023/2024 Portuguese rugby season. Five of the ten eligible teams competing in the Portuguese Senior Male Rugby Union XV Championship participated in the study. Team medical staff prospectively recorded all time-loss match injuries using a standardized online reporting form. Results: The overall injury incidence was 49.46 injuries per 1000 player-match-hours (95% CI: 39.78–59.68), with a mean injury severity of 12.80 days (SD = 12.17). Lower-limb injuries accounted for 52.2% of all injuries and were associated with the greatest mean time-loss (15.56 days). Bone injuries demonstrated the highest descriptive mean injury severity. However, this finding was based on a small number of cases and should therefore be interpreted with caution. A weak but statistically significant positive correlation was observed between exposure hours and injury severity (r = 0.26, p = 0.011). Conclusions: The findings indicate that injuries in Portuguese top-tier rugby occur predominantly during contact events and in the second half of matches. Lower-limb injuries were the most frequently reported injuries and accounted for the largest proportion of time-loss injuries. Full article

Climate change is increasing the frequency, intensity, and duration of heatwaves, making extreme heat a recurrent public health challenge with important nutritional implications. High ambient temperatures affect human health through thermoregulatory strain, sweating, dehydration, electrolyte imbalance, cardiovascular and renal stress, impaired cognitive and physical performance, and exacerbation of chronic diseases. Diet and hydration may therefore represent modifiable, although still underinvestigated, components of heat-health prevention. This narrative review synthesizes evidence on hydration, electrolyte balance, meal composition, dietary quality, vulnerable populations, Mediterranean dietary patterns, seasonality, environmental sustainability, and public health strategies for reducing heat-related health risks. Evidence from climate-health research, physiology, nutrition science, occupational and sports medicine, geriatrics, pediatrics, and public health guidance was integrated. Particular attention was given to distinguishing direct heat-health evidence from recommendations based on indirect evidence, physiological plausibility, or expert consensus. Regular water intake, water-rich foods, avoidance of alcohol, moderation of sugar-sweetened beverages, and individualized electrolyte replacement during prolonged or intense sweating are supported by physiological rationale and public health guidance, although direct heatwave-specific intervention studies remain limited. Dietary recommendations should prioritize smaller, digestible, nutrient-dense meals that preserve nutritional adequacy while reducing unnecessary digestive and metabolic burden. However, evidence on meal size, macronutrient composition, and heat-related outcomes remains largely indirect. Vulnerable groups, including older adults, children, pregnant women, individuals with chronic diseases, outdoor workers, athletes, and socioeconomically disadvantaged populations, require tailored strategies. The Mediterranean diet may provide a useful regional model because it emphasizes seasonal plant foods, fruits and vegetables with high water content, legumes, whole grains, olive oil, culinary simplicity, and environmental sustainability; however, its specific role in heat adaptation requires further study. Integrating nutrition and hydration into heat-health action plans may improve preparedness and support climate-resilient food systems. Future studies should evaluate hydration protocols, meal patterns, Mediterranean diet adherence, biomarkers of nutritional heat resilience, and nutrition-sensitive interventions in real-world heat exposure settings. Full article

Proxy indicators have been proposed as practical screening tools to assess low energy availability (LEA) risk among athletes. We evaluated the utility of the Low Energy Availability in Females Questionnaire (LEAF-Q), resting metabolic rate (RMR) ratio, and relative RMR (rRMR) in identifying LEA risk compared with estimated energy availability (EA). Twenty mixed-sport female athletes (24.8 ± 4.8 years) participated in this cross-sectional study. EA was estimated using four-day food and activity logs. LEAF-Q scores were obtained via questionnaires. RMR was measured via indirect calorimetry while predicted RMR was calculated using the 1980 Cunningham equation. RMR ratio was computed using measured RMR over predicted value, and rRMR computed using measured RMR over fat-free mass (FFM), as assessed by dual-energy X-ray absorptiometry. Participants were classified ‘at risk’ of LEA based on LEAF-Q score ≥8, RMR ratio <0.90, and rRMR <30 kcal/kg FFM/day. RMR-derived measures displayed high sensitivity (100%) and low specificity (44.4%), while LEAF-Q exhibited low sensitivity (27.3%) and moderate specificity (55.6%). EA was moderately correlated with RMR ratio (r = 0.47, p = 0.035) and strongly correlated with rRMR (r = 0.63, p = 0.003). RMR-based measures may be promising rapid screening tools for LEA risk in mixed-sport female athletes. Full article