International journal of exercise science最新文献

Knee injuries are very common in soccer players. High loads on the knee during landing or changes of direction can lead to a valgus shift of the knee, known as Dynamic Knee Valgus (DKV). Many studies have shown that a large shift in DKV is a predisposing factor for knee injuries and disease, such as anterior cruciate ligament injury (ACL), patellofemoral pain syndrome or osteoarthritis. Functional training could be a great tool to reduce DKV. Thus, in this pilot study, nine male youth soccer players (mean age: 16.4 ± 0.2 years) took part in six weeks of functional training program. DKV was measured in pre- and post-measurements during single leg squats using Kinect Azure camera with DynaKnee software. In addition, maximal voluntary muscle contraction (MVC) was measured using a dynamometer and muscle activation amplitude (MAA) was measured using electromyography. Data were analysed using a non-parametric Wilcoxon signed rank test to assess differences in DKV, MAA and MVC at a 5% significance level. Data showed a small improvement of DKV in the dominant leg. MVC increased slightly in all variables. The MAA of the involved muscles in the single-leg squat did not show a higher value, but rather a decreasing trend. However, none of the analyses showed significant changes. The small number of participants and the short duration of the training might have been a limiting factor. Further studies should repeat the procedure with a larger group of participants and a longer training period.

Cooling glabrous skin sites, such as the palms, can mitigate core body temperature rise and delay fatigue during physical activity, potentially enhancing performance. However, research on palm cooling (PC) in female athletes remains limited, and existing devices are often costly or impractical. This study evaluated the effects of PC using a novel, cost-effective portable device on repeat sprint ability in female collegiate athletes after a fatiguing protocol. Twenty female athletes (age: 20.1±1.4 years; height: 166.7±6.9 cm; mass: 66.6±9.8 kg; BMI: 24.0±3.9 kg/m²; body fat: 24.9±4.6%) participated in a randomized crossover study. Sessions included a modified Loughborough Intermittent Shuttle Test (LIST) followed by a 20-meter repeat sprint test. Athletes used either the PC device (7-15°C) during rest intervals or no cooling (NC). Physiological (heart rate, blood lactate), perceptual (RPE, thermal perception, affect), and performance outcomes (number sprints) were recorded. PC resulted in significantly more successful sprints (≥90% of maximum velocity) than NC (10.3±12.9 vs. 6.0±8.4; p=0.025). No significant differences were observed in perceptual or physiological measures (p>0.05). Palm cooling with a portable device improved repeat sprint ability in female athletes, supporting its use as a practical performance optimization strategy. Further research is warranted to investigate underlying mechanisms and applications across different sports and environmental conditions.

This study is the first to investigate the role of mental toughness (MT) in predicting strength and conditioning (S&C) performance outcomes and the impact of pressure training (PT) on MT development among NCAA athletes. A women's Division I field hockey team (n = 15) participated in five 1- hour sessions focused on psychological skills training to enhance MT, followed by two S&C sessions under PT conditions. Using the Mental Toughness Index, MT was assessed after the workshops/before PT and following PT. Regression analysis revealed that pre-PT MT scores predicted S&C performance outcomes during PT sessions (F(1, 16) = 4.67, p = .0499, 95% CI [0.154, 0.803]), with a positive correlation between MT scores and performance (R2 = 0.26, β = 0.07, 95% CI [0.00, 0.15]). A paired samples t-test revealed a significant increase in MT scores post-PT (t(12) = -3.34, p = .006, d = 0.93, 95% CI [-3.31, -0.69]), suggesting PT effectively enhances MT. PT sessions incorporated relevant-to-the-team demands and consequences, incidentally leading to increased athlete engagement and performance intensity. Overall, the findings demonstrate the relevance of PT as an innovative and practical tool for S&C coaches, offering initial evidence of its capability to enhance athlete development and optimize performance under high-stake conditions with strong ecological validity due to its application in real-world training environments. Future research should explore the longitudinal application of PT across larger samples, diverse sports, and its long-term effects on performance outcomes.

In martial arts, heart rate variability (HRV) measurements can potentially be used to assess injury risk and susceptibility to fatigue. Muay Thai uses the Frequency Speed of Kick Test (FSKT) to measure kick speed, but it is unknown whether better fitness results in improved autonomic function and body composition, which may affect athletic performance and recovery. We aimed to evaluate the correlations between FSKT, HRV, and body composition measures in amateur Muay Thai fighters. This is a cross-sectional study with 37 Muay Thai fighters. They underwent FSKT-10s and multiple FSKT to measure the kick fatigue index (KFI). In addition, body composition was assessed using bioelectrical impedance analysis and HRV using a heart rate monitor. When comparing the values before and during the FSKT-10s, there was a decrease in the percentage of interval differences of consecutive successive NN intervals greater than 50 ms (pNN50), approximate entropy, and parasympathetic nervous system (PNS) index, with an increase in the sympathetic nervous system (SNS) index. The number of kicks assessed by FSKT-10s positively correlated with fat-free mass (FFM) and low frequency (LF) of the HRV assessment. The KFI correlated negatively with the FFM and PNS index, and positively with the LF and SNS index. When amateur Muay Thai fighters perform the FSKT-10s, there is an acute effect on autonomic modulation with increased sympathetic activation and vagal withdrawal. FFM and sympathetic activation are related to performance and susceptibility to fatigue. These results indicate the importance of assessing HRV in Muay Thai fighters to improve performance.

Obese adults are faced with greater challenges to maintaining balance compared to their healthy-weight counterparts. Due in part to the ongoing national and global obesity epidemic, it's imperative to identify if body mass index (BMI) could negatively affect postural control and balance. The purpose of this study was to determine if CoP scores displayed a significant relationship with BMI in healthy adults. Cross-sectional, archival data from 225 adults (40 males; 185 females; age 29.6 ± 14.25 years; weight 77.95 ± 21.33 kilograms [kg]; height 168.43 ± 0.66 centimeters [cm]; BMI 27.52 ± 0.42 kg/m²) were analyzed. Four (4) CoP scores were collected using a Bertec® Dynamic Computerized Posturography Plate (Bertec, Columbus, OH) including Normal Surface Eyes Open (NSEO), Normal Surface Eyes Closed (NSEC), Perturbed Surface Eyes Open (PSEO), and Perturbed Surface Eyes Closed (PSEC). Pearson's correlation coefficients were used to determine if there were significant (p < 0.05) relationships between each of the 4 CoP conditions with BMI. A significant, weak negative relationship (r = -0.180; p = 0.007) was demonstrated between BMI and NSEO condition. Weak, insignificant negative relationships were demonstrated between BMI and NSEC (r = -0.065; p = 0.33) and PSEO (r = -0.021; p = 0.70) conditions. A weak, insignificant relationship was demonstrated between BMI and PSEC (r = 0.075; p = 0.25) condition. Obesity, as indicated by BMI, could lead to poorer postural control under normal surface, eyes open conditions.

Many law enforcement organizations are experiencing recruitment and retention challenges, of which physical fitness can be a factor. The study purpose was to collate information from Peace Officer Standards and Training (POST) Commission staff in each USA state to document current fitness mandates and policies for recruits/officers. A 10-question survey was allocated to an appropriate representative from every state POST organization. The survey collected information regarding minimum state-mandated fitness standards for academy entry and exit; minimum state-mandated requirements for fitness programming, including safety plans; education/training requirements for fitness training instructors; and minimum state-mandated fitness standards for incumbent officers. The response rate was 98% (49/50 states). Fewer than half of the states mandated: age- and gender-neutral statewide academy entry fitness tests (29%; n=14); ability-based fitness training (24%; n=12); minimum education or formal certifications for fitness training instructors (45%; n=22); statewide collection of fitness (25%; n=12) or injury (45%; n=18) data; a statewide fitness training safety plan (40%; n=19); age- and gender-neutral exit fitness tests for recruits/students (35%; n=17); and officer fitness standards (8%; n=4). Only thirteen states (27%) had an active work group focusing on survey topics. POST Commissions should be proactive in reviewing minimum fitness requirements for academies, and staff should continue and/or expand fitness education. Resources are available for POST Commissions to design/update safety plans and address other findings. Although difficult to mandate fitness standards for officers, they should be provided resources to remain physically active. Implementing these practices via appropriate policies should assist with personnel health and retention.

Sport science serves many crucial functions in facilitating improvements in human performance, including advancing inclusivity. This may be realized through the conceptual framework of Adaptive Synergy, which integrates Adapted Physical Activity for athletes with physical disabilities while simultaneously optimizing athletic performance for all individuals. This paper introduces the Adaptive Synergy conceptual framework to sport science, applying this cross-disciplinary concept to biomechanics, exercise physiology, sport psychology, and neuroscience to more specific application of adaptive techniques and methods, which are essential to improving both accessibility and innovation in sports. Key areas of focus include the anatomical impairments of athletes with physical disabilities, their unique psychological needs, development of adaptive equipment, the implementation of tailored, evidence-based training protocols, and the reduction of financial and educational barriers to inclusivity. The Adaptive Synergy framework enables coaches and sport scientists to provide equitable opportunities for all athletes, exemplified by the creation of inclusive training environments, specialized coaching methodologies, and affordable sport participation programs. By fostering a culture of cross-disciplinary collaboration, this approach promotes the physical, mental, and social development of athletes with physical disabilities while driving innovation in sports performance for all. Consequently, Adaptive Synergy represents a transformative model that merges inclusivity with the pursuit of athletic excellence across diverse populations.

The purpose of this study was to understand whether or not physiological and biomechanical measures were influenced by cycling sway and intensity. Participants (n=13; 24.9±6.5 years; 1.7±0.1 m; 64.7±11.2 kg) completed two submaximal-effort cycling conditions using a stationary smart bike placed on a rocker board: 1) cycling with the rocker board set to allow sway (unblocked); 2) cycling with blocks placed in the rocker board to prevent sway (blocked). The order conditions were counterbalanced, and each condition was 12-mins. For each condition, four intensity levels were completed. Prior to testing, target power was identified for each Rating of Perceived Exertion (RPE) level (11, 13, 16, 17). Rate of oxygen consumption (V^·O₂; ml·kg^-1·min^-1) was measured using a metabolic cart (1 sample every 5 sec) along with RPE and heart rate (HR). Cadence, speed, and power were measured via the smart bike interface for each condition. Sway was measured using a custom rotary switch that measured (250 Hz) the angle of the rocker board while cycling. Each dependent variable was compared using a 2 (Condition: blocked, unblocked) x 4 (Intensity) repeated measures ANOVA. For sway, V^·O₂, HR, speed, and cadence, there was no interaction between Condition and Intensity (p>0.05). Sway was influenced by the main effect of Condition (p<0.001). V^·O₂, HR, and speed were each influenced by the main effect of Intensity (p<0.001). Overall, it was determined that participants did sway when there was the potential to sway; however, physiological or biomechanical measures were not influenced by the ability to sway.

Cardiovascular fitness (VO_2max) predicts all-cause mortality and is vital to assess in cancer survivors (CS) for individualized exercise prescriptions. Metabolic carts confirm VO_2max with respiratory exchange ratio (RER) ≥1.10; other VO_2max criteria include ≤10 beats/minute of maximal predicted heart rate and/or a rating of perceived exertion (RPE) of >8 on the Modified Borg Scale. Another suggested criterion is respiratory frequency (Rf) ≥ 40 breaths per minute. These criteria are assumed applicable for all populations, but due to cancer-related toxicities, frequency and validity of traditional VO_2max criteria usage in CS remains unconfirmed. The purpose was to evaluate the frequency of VO_2max criterion achievement of RER and alternate maximal criteria using HR, RPE, and Rf in CS. Forty CS performed three graded exercise tests (GXT) using gas analysis, totaling 111 GXTs. Max RER, HR, RPE, and Rf were measured. Differences in successful VO_2max criterion achievement frequency were assessed using a Cochran's Q test and Pairwise Comparison Dunn test with Bonferroni adjustment. Maximal criteria were successfully met in 84%, 79%, 92%, and 43% of trials when evaluating RER, HR, RPE, and Rf, respectively. Significant differences occurred between Rf and all other measures (p < 0.001); no significant differences occurred between RER, HR, RPE. Traditional VO_2max criteria may be feasibly obtained and used in CS; HR and RPE are valid alternatives to RER, but Rf is not. The equivalency between RER, RPE, and HR suggests metabolic carts may be unnecessary for CS during maximal testing, increasing accessibility and validity of VO_2max values.

[This corrects the article DOI: 10.70252/EJIJ5619.].