International journal of sports medicine最新文献

This study determined and compared the second muscle oxygenation threshold (MOT2) in the vastus lateralis (VL) (more active) and biceps brachii (BB) (less active) muscles in the graded exercise test (GXT). Furthermore, we investigated the correlation between BB and VL MOT2 with the 3,000-m time trial, as well as the muscle oxygenation responses during the free-paced strategy of elite endurance athletes. Nine elite men's middle- and long-distance runners from the Brazilian Paralympic Endurance Team performed the GXT in a laboratory setting. MOT2 was determined by the breakpoint in the tissue saturation index (TSI) curve in both muscles by wearable near-infrared spectroscopy (NIRS). After 48 h, athletes performed a 3,000-m running test on an outdoor athletics track while monitoring the oxygenation in both muscles. MOT2 velocity values in BB (19.3±1.3 km.h^-1) and VL (19.4±1.2 km.h^-1) did not show a significant difference between them (p>0.05). We observed a significant correlation between BB and VL MOT2 with 3,000-m mean velocity (r=0.88 and 0.86, respectively, p<0.05). Our results reinforce that the maximal aerobic capacity determined in different muscles influenced the athletes' performance in the 3,000-m running. The muscle oxygenation responses showed that BB and VL worked in an integrated manner during the GTX and in the 3,000-m running effort.

This study evaluated the reliability, sensitivity, and performance changes in physical tests in highly trained adult female football players over the course of a competitive season. Twenty players (21.1±2.72 years) participated in this study. Tests included bilateral and unilateral countermovement jumps, unilateral horizontal jumps, 40-m linear sprints, and change-of-direction (COD) tests (COD180° and V-cut). Relative and absolute reliabilities were analyzed. Sensitivity was determined by comparing the smallest worthwhile change to the typical error of measurement and, in addition, changes in performance over the season were assessed in short-, medium-, and long-term periods. Results demonstrated high reliability across all tests, with intraclass correlation coefficient values ranging from 0.70 to 0.94 and coefficient of variation (CV) below 5%, meeting a priori reliability criteria. Vertical jumping exhibited the highest reliability (0.89-0.92) and was sensitive in detecting moderate-to-large changes. COD tests showed moderate-to-high reliability (0.70-0.89), with CODR180° sensitive to seasonal adaptations. Sprint tests also displayed good reliability (0.80-0.94); however, their sensitivity was limited. Notably, the unilateral jump tests and CODR180° exceeded CV thresholds, highlighting their potential to monitor significant improvements over time. Unilateral and COD-specific assessments emerged as particularly valuable for detecting performance changes, underscoring the need for sport-specific testing protocols in women's football.

Overtraining syndrome (OTS) is characterised by persistent fatigue and performance decline, but it currently lacks specific diagnostic criteria and medical coding. Diagnosis is primarily based on a decline in maximal performance and a subjective feeling of 'staleness', after ruling out other medical conditions. This study aimed to identify physiological and self-reported predictors of OTS by comparing individuals diagnosed with OTS (n=110; 2008-2022) with a healthy control group (n=447; 2005-2023). Both groups consisted of athletes and recreational exercisers assessed at the Helsinki Sports and Exercise Medicine Clinic (HULA). Data were collected through questionnaires and spiroergometric testing and subsequently analysed using logistic regression, adjusting for age and sex. The results of this study suggest that fatigue, dizziness and shortness of breath, along with decreased maximum oxygen uptake (V̇O2_max), peak blood lactate value (La_max) and oxygen uptake at both ventilatory thresholds (V̇O_2VT1 and V̇O_2VT2), are significant predictors of OTS (p<0.05/54). Among reported health conditions, asthma, allergy, anaemia and mental health issues were statistically significant predictors of OTS at the 0.05 level, but not after Bonferroni correction. In conclusion, regular spiroergometric testing and symptom monitoring may support earlier diagnosis and improved management of OTS in athletes and recreational exercisers.

Sports participation entails a considerable risk of injury and prevention of health problems is an important goal for clinicians and researchers. A carefully designed injury and illness surveillance program, accurate data capture and careful analysis of data are building blocks for the implementation of prevention programs. We included in our narrative review papers addressing definitional issues and how to report data on injury and illness surveillance, papers addressing how to explore impact and effectiveness of surveillance procedures for sports injuries and illnesses and papers comparing different surveillance approaches. Different methods and approaches alongside key definitions and concepts on health problem surveillance have been proposed during the last 30 years trying to address the main features clinicians and researchers should adopt to conduct appropriate injury and illness surveillance. The literature suggests that the collection of a core set of variables including location, tissue and pathology type, relation to sports activity, mode of onset, mechanism, and severity is needed to conduct appropriate injury and illness surveillance. Definitions and modalities should be clarified at the beginning of the surveillance and data collection should be safe and on time.

This study explored the effect of knee range of motion (ROM) restrictions on lumbar spine kinematics and posterior chain muscle activity during squat and stoop lifting tasks. This relationship reflects the concept of regional interdependence, where impairments in one anatomical area may influence others, a key principle in the kinetic chain approach. Fifteen healthy adults performed squat and stoop lifting tasks under three knee ROM conditions (squat: free/0-60°/0-90°; stoop: free/0°/0-30°) using optoelectronic motion capture and electromyographic (EMG) systems. One-way analysis of variance was applied to analyze lumbar spine angles in flexion/extension, side bending, and rotation and to assess muscle activation patterns for five posterior chain muscles. No significant effects of knee ROM restrictions were observed for lumbar flexion/extension or side bending (p>0.15), but pelvic rotation differed significantly (p=0.0103). EMG analysis showed increased activation of the Gastrocnemius Lateralis and Biceps Femoris (p<0.001), while Gluteus Maximus and Latissimus Dorsi activation remained unchanged. Knee ROM restrictions influenced EMG muscle activation in distal posterior chain muscles and altered pelvic rotation, suggesting localized compensatory mechanisms. Results highlight the variation in muscle activation patterns and kinetic adjustments during squat and stoop lifting tasks in healthy individuals simulating knee ROM deficits, osteoarthritis, or low back pain conditions.

This systematic review and meta-analysis aimed to evaluate the effect of velocity-based training (VBT) conditioning activities (CA) on subsequent athletic performance and explore how different CA types, velocity loss (VL) thresholds, loads, sets, participants, and rest intervals influence postactivation performance enhancement (PAPE). Six electronic databases were searched. Nine studies were included, reporting 18 effect sizes and comprising 152 participants. We assessed pre- and posttest differences using meta-analysis, conducted subgroup analyses to identify potential moderating factors, and employed nonlinear meta-regression to explore the relationship between rest intervals and the PAPE effect. The results showed that VBT-CA significantly improved athletic performance. Subgroup analyses showed no significant differences; nevertheless, bench press-type CA, CA with VL≤10%, load≥80% one-repetition maximum (1RM), single-set CA, and athlete population exhibited a trend toward larger PAPE effects. Between 5.77 and 12.8 minutes after VBT-CA, a significant PAPE effect was indicated by the meta-regression results, with the optimal time point being 8.96 minutes. Our study suggests that VBT-CA can effectively induce the PAPE effect. Individuals seeking to improve their athletic performance could consider performing a single set of CA with load≥80% 1RM, VL≤10%, 5.8-12.8 minutes before the explosive activity.

This study investigates bilateral and unilateral strength imbalances in elite young football players across different age categories. A total of 73 licensed male football players in the U15, U16, U17, and U19 age categories participated in the study. Imbalances between the legs were assessed by both jump tests and differences between hamstring and quadriceps strengths. Differences between age groups were statistically evaluated by one-way analysis of variance and linear regression analysis. The results showed that the hop test asymmetry index (AI), Q/Q, and H/H strength ratios decreased from U15 to U17 and increased again at U19 (p=0.037, p=0.025, p=0.002). Regression analysis revealed that age significantly influenced the hop test AI (5%), Q/Q strength ratio (5%), H/H strength ratio (12%), and dominant leg H/Q strength ratio (7%) (p<0.05). Overall, this study shows that muscle strength imbalances in young soccer players differ both bilaterally and unilaterally with age. While bilateral strength differences were relatively balanced in the U15-U17 age groups, a significant asymmetry was observed in the U19 group. In terms of unilateral strength, a certain development was observed in the dominant leg with age, while this development was limited in the nondominant leg.

Based on previous research, catchers' throwing mechanics between baseball and softball tend to be viewed as comparable despite the inherent differences in playing conditions. When compared at key throwing timepoints, differences in pelvis and trunk kinematics were observed between sports. However, it is uncertain whether throwing-arm mechanics would differ throughout the throw between these athletic populations. Therefore, this study aimed to compare catchers' throwing mechanics between sports using continuous statistical analyses. A total of 20 catchers (baseball: n=10 and softball: n=10) participated in this study. Statistical parametric independent samples t-tests (α=0.05) were used to temporally compare proximal and throwing-arm kinematics from foot contact (0%) to maximum shoulder internal rotation (100%) between sports. Differences found included elbow flexion (p=0.008; 0-13 and 99-100%), shoulder rotation (p<0.001; 23-53%), elevation (p<0.001; 0-95%) and the plane of elevation (p<0.001; 0-100%), pelvis and trunk lateral flexion (pelvis: p=0.027; 0-30% and trunk: p<0.001; 23-100%) and rotation (pelvis: p=0.036; 4-21% and trunk: p=0.036; 84-100%), and trunk flexion (p<0.001; 34-100%). While most of the observed differences were brief, notable differences in the trunk flexion, trunk lateral flexion, shoulder elevation, and plane of elevation were apparent for much of the throwing motion. Time-series analyses identified distinct mechanics involved in baseball and softball throw downs, lending support for sport-specific biomechanical assessments on catchers.

The literature has identified inconsistent biomechanical risk factors for running-related injuries but lacks investigations on interactions between biomechanics and other risk factors. This prospective cohort study aimed to develop and compare prediction models of various levels of complexity to predict running-related injuries over 12 months in recreational runners. The seven-item functional movement screen test was administered at baseline for 83 participants. Running biomechanics were evaluated using clinically friendly tools, including wearable in-shoe force sensors to measure vertical ground reaction forces and 2D video-based kinematic analysis of lower extremities. The participants were subsequently monitored over a 12-month follow-up period to track whether they sustained running-related injuries. Differences between the injured (n=26) and non-injured (n=55) groups were examined using the Mann-Whitney U-test. Binary logistic regression was performed to identify significant indicators for running-related injuries, with six models developed involving different sets of variables. Neither simple (involving one variable) nor complex models (including multiple variables) were statistically significant (p-values ranged from 0.106 to 0.972). In conclusion, prediction models developed using variables obtained from accessible tools are unable to accurately predict future running-related injuries regardless of model complexity. Researchers and practitioners should avoid over-reliance on simple measures for screening injury risks.

Aging is a complex biological process driven by the dynamic interplay among genetic, environmental, and lifestyle factors. Advances in epigenetics have significantly deepened our understanding of the molecular mechanisms underlying aging, underscoring the critical roles of reversible modifications such as DNA methylation, histone modifications, and noncoding RNA regulation. Emerging evidence suggests that exercise is a potent modulator of these epigenetic processes, capable of reshaping the epigenetic landscape to restore cellular homeostasis, modulate gene expression, and enhance physiological resilience. This review systematically synthesizes current knowledge on how exercise modulates epigenetic mechanisms implicated in aging and delineates the distinct epigenetic adaptations induced by variations in exercise modality, intensity, and duration. By integrating these molecular insights, this review provides a comprehensive mechanistic framework linking exercise-induced epigenetic remodeling to healthy aging, and underscores exercise as a promising intervention to counteract aging-related functional decline and disease progression.