Journal of Human Kinetics最新文献

This study investigated the effects of an on-ice resisted sprint training (RST) intervention, an overground RST intervention and a traditional training control condition on measures associated with ice skating completion time. The vertical jump, the broad jump, the isometric mid-thigh pull, and overground sprint completion times, along wth sprint kinetics and kinematics were obtained prior and at the conclusion of the 8-week training intervention. There was a 7% increase in jump height (p < 0.05), a 9% increase in the jump peak force (p < 0.05), a 10% increase in jump peak power and a 21% increase in broad jump distance (p < 0.001) across all groups. Only the overground RST group significantly improved by 12% (p = 0.007) in the isometric mid-thigh pull peak force. All groups decreased 9.14-m completion time (-3%), 36.58-m completion time (-4%), and flying 30-m top speed completion time (-9%) (p < 0.05). The on-ice RST group improved by 22% in theoretical maximal horizontal force, 24% in theoretical maximal horizontal power, and 7% in the maximal ratio of force (p < 0.05). The step rate decreased by -2%, and the trunk angle increased by 48% at the touchdown and 30% at the toe-off for the overground RST group (p < 0.05). RST and bodyweight training induced comparable changes across most overground athletic performance measures associated with ice skating. Coaches desiring to improve overground predictors of ice skating performance in ice hockey players may benefit from incorporating RST as a component of a well rounded strength and conditioning program.

There are few studies that clarify the level of muscle activity in the trunk and pelvis muscles during sprinting. This study aimed to investigate muscle activity in the trunk and pelvis muscles during sprinting using T2-weighted magnetic resonance imaging (MRI). The pre- and post-test designs were employed by measuring trunk and pelvis muscle activity using T2-weighted MRI before and after 60-m round-trip sprints. Ten male sprinters (N = 10, age, 23.3 ± 6.7 years; body height, 175.1 ± 3.6 cm; body mass, 66.8 ± 4.3 kg; 100-m personal record, 11.18 ± 0.48 s, means ± standard deviations [SDs]) performed three sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3T MRI scans were performed to obtain the T2 values of the trunk and pelvis muscles. After the 60-m roundtrip sprints, the T2 values of lateral abdominal, psoas major, erector spinae, gluteus maximus, gluteus medius, rectus femoris, tensor fasciae latae, sartorius and pectineus muscles increased significantly. There were intermuscular differences in the rate of change of T2 values before and after the 60-m round-trip sprints, with significantly higher levels of muscle activity in lateral abdominals, psoas major, erector spinae, gluteus maximus, and pectineus. In sprinting, the trunk and pelvis muscles were found to be specifically activated.

Continual exercise has become an important concept for mental as well as physical health, with sporting industries and communities interested in promoting exercise adherence. This study examined the causal relationship among sports ability-beliefs, achievement goal orientation, and exercise adherence among Korean recreational golfers. Data from 806 golfers were collected after Institutional Review Board deliberation and approval. To reflect the characteristics of frequent participation, golfers were limited to those who had been registered members of a golf practice facility for more than three months. The measurements included the sports ability-belief scale, the achievement goal orientation scale, and the exercise adherence scale, with evidence of construct validity based on confirmatory factor analysis. The research questions were verified through a measurement model and structural model validation. The results showed that the learning factor under incremental beliefs explained task orientation (β = 0.417, p < 0.001). Conversely, the gift factor under entity beliefs explained ego orientation (β = 0.169, p < 0.001). Thus, the significant relationship between learning and task orientation implied that consistent practice and effort in golf could enhance the positive meaning of golf participation and the perception of achievement in golfers. Conversely, the static explanation of ego orientation of gift suggested that individuals with strong beliefs in their innate golf abilities or the influence of their motor skills on golf performance experienced a sense of achievement by comparing themselves with others. Secondly, when the sub factors of sports ability-beliefs were controlled, both task orientation (β = 0.420, p < 0.001) and ego orientation (β = 0.159, p < 0.001) were statistically significant in terms of exercise adherence. Thirdly, in the relationship between sports ability-beliefs and exercise adherence, both task orientation (indirect effect: 0.074, p < 0.001) and ego orientation (indirect effect: 0.012, p < 0.05) had complete mediation effects. Ultimately, the study confirmed that the relevance of sports ability-beliefs and achievement goal orientation for exercise adherence in elite sports could also be applicable in the realm of recreational sports.

High-intensity interval training (HIIT) has emerged as a time-efficient mode of exercise. However, there is limited evidence that HIIT improves inhibitory control and working memory (WM) more than moderate-intensity continuous exercise (MICT). This study aimed to explore the effects of HIIT, moderate-intensity interval exercise (MIIT), and MICT on inhibitory control and WM in healthy adults. Twenty-five healthy college students (21.04 ± 2.44 years; 14 females) were recruited to complete HIIT, MIIT, MICT, and a resting session (CON) for 15 min in a randomized crossover design. The HIIT protocol comprised three 3-min bouts at 90% of the maximum heart rate (HR_max) with 2 min of active recovery at 70% HR_max. The MIIT protocol comprised three 3-min bouts at 70% HR_max with 2 min of active recovery at 50% HR_max. A volume-matched MICT protocol was applied at 70% HR_max. The Stroop and 2-back tasks were used to evaluate inhibitory control and WM in post-trials, respectively. Response times (RTs) of the Stroop task significantly improved on the congruent condition in the HIIT session compared to the CON session (p = 0.004, Cohen's d = 0.64), on the incongruent condition in the HIIT session compared to MICT (p = 0.049, Cohen's d = 0.42) and CON (p = 0.023, Cohen's d = 0.49) sessions, and on the neutral condition in the HIIT session compared to MIIT (p = 0.029, Cohen's d = 0.47) and CON (p = 0.012, Cohen's d = 0.55) sessions. Hits in the 2-back task increased significantly following HIIT compared to MIIT (p = 0.041, Cohen's d = 0.43), MICT (p = 0.02, Cohen's d = 0.5), and CON (p = 0.006, Cohen's d = 0.6). We concluded that a single bout of HIIT effectively improved inhibitory control and WM in healthy adults. These findings support the practical implication of HIIT being beneficial within a short time for enhancing inhibitory control and WM in clinical populations.

The aim of this study was to develop international standards for evaluating strength endurance abilities with the use of the 12-min Cooper Test on a rowing ergometer (12-MCTRE). The results from 1855 men (1421 from Poland and 434 from Hungary) and 2879 women (2502 from Poland and 412 from Hungary) aged 19-25 (mean age of 19.98 ± 1.04 and 20.36 ± 0.94, respectively) were collated between 2004 and 2020. The results were expressed on a uniform T-score scale for the 12-MCTRE. The validity of the 12-MCTRE was verified on a group of 28 male and 32 female participants based on the registered variables (power [W], energy expenditure [Kcal], training intensity distribution, and sexual dimorphism). On average, men covered a distance of 2535.6 m and women covered a distance of 1581.0 m during the 12-MCTRE. The results of the control group indicate that men covered a significantly (p < 0.001) longer distance (2691.5 m) than women (2116.1 m) in the 12-MCTRE, and the values of the remaining variables (power, energy expenditure, pace/500 m, and HR_max) were also significantly better in male participants. During the 12-MCTRE, both women and men remained in the very high effort zone for the longest period of time (516.9 s and 363.1 s, respectively). Women spent significantly more time (p < 0.001) in the high effort zone than men, but significantly less time in the maximal effort zone and the very high effort zone. The 12-MCTRE is an effective tool for evaluating strength endurance abilities in young adults.

The present study aimed to investigate how players' technical actions were influenced by different touch restrictions in small-sided games (SSGs). Specifically, it analysed differences in the temporal intervals separating players' first and second touches across varied field zones-defensive, centre, and offensive-in SSGs. The experimental design involved twelve male junior soccer players playing under three distinct 4v4 SSG conditions: 1) a maximum of two touches per player; 2) a maximum of three touches per player; and 3) unrestricted play with no touch restrictions. Ten games of 4v4 SSGs (4 players + goalkeeper per team) were held for each condition, resulting in a total of 30 games of 4v4 SSGs investigated across eight distinct test sessions. Players had the shortest intervals between their first and second touches in the offensive zone, followed by the centre and then the defensive zones. Furthermore, the imposition of touch restrictions in SSGs led to a heightened frequency of passes compared to SSGs characterised by unrestricted gameplay; by contrast, SSGs featuring free play facilitated a greater number of receptions compared to SSGs with constraints on the number of touches. In conclusion, the current study outlines distinct differences in temporal intervals between the first and second touches of the ball across distinct field zones, notably showcasing a significant reduction in the time elapsing between touches as players neared their opponents' goal.

The aim of the study was to investigate the prevalence of the relative age effect (RAE) among elite Olympic weightlifters in different age groups. The prevalence of RAE was studied among top 10 participants from the World Weightlifting championships for youth, junior and senior age groups and from the Olympic Games from 2009 to 2022. Birth dates of 3886 athletes were analyzed and further divided into four groups according to the birth quartile. Weight categories were grouped as lightweight, middleweight and heavyweight. The effect was found among lightweight and heavyweight girls, boys of all weight groups, lightweight and middleweight junior females and juniors of all weight groups. In the senior group, RAE was only present among heavyweight males. Differences in the prevalence of RAE between male and female weightlifters were statistically significant (p = 0.009). Differences in effect between youth and junior age groups were not significant (p = 0.24). The findings of this study demonstrate that RAE tends to be widespread among the best weightlifters of both sexes in youth and junior age groups, but disappears in most weight groups at the elite senior level.

Low back pain (LBP) is a widespread musculoskeletal condition caused by various pathologies, including peripheral nervous system dysfunction, resulting in stiffness, reduced strength, and compromised neuromuscular control. Therefore, this study aimed to evaluate the influence of single-leg radicular pain on hamstring biomechanics in young adults without significant concurrent lower back symptoms while investigating the association between the functional outcome and muscle biomechanical properties. This cross-sectional study included two groups: young adults with lower limb radicular pain (RAD, n = 15) and age-matched healthy asymptomatic individuals (CON, n = 15). Clinical characteristics were assessed using the Oswestry disability index (ODI), the numeric pain rating scale (NPRS), and the passive straight leg raise (PSLR) test. Myometric muscle analysis of the biceps femoris and semitendinosus muscles was conducted using the Myoton PRO® device, focusing on mechanical and viscoelastic properties such as frequency, stiffness, relaxation time, decrement, and creepability. The RAD group showed around 14% higher stiffness on the symptomatic side compared to the CON group (p = 0.003), while relaxation time and creepability were by approximately 14% (p = 0.008) and 13% (p = 0.01) lower, respectively. Similarly, the RAD group exhibited approximately 13% higher stiffness on the asymptomatic side compared to the CON group (p = 0.02). In conclusion, the biomechanical properties of the hamstrings-particularly stiffness, relaxation time, and creepability of the biceps femoris on the symptomatic side-may significantly impact pain management in individuals with radicular pain. Moreover, stiffness of the biceps femoris could be an important predictor of functional outcomes in younger adults.

The aim of this study was to build an XGBoost model to predict the match outcome and analyze match-related technical, tactical and physical performance features that may influence the predicted outcome of the match. This is an observational study which follows a retrospective design. The FIFA post-match summary reports were downloaded at the end of the 2023 Women's World Cup and used to create a dataset which consisted of match-related technical, tactical and physical performance variables. Then, an XGBoost model was built to predict the match outcome and investigate which performance features might influence the predicted outcome of the match. The overall model achieved accuracy of 0.58 ± 0.05. Losses and wins had similar predictive accuracy (0.67 ± 0.06 and 0.67 ± 0.08, respectively), but the prediction of draws performed was significantly worse with accuracy of 0.32 ± 0.16. The top ten features for predicting wins were: (1) out to in actions by the opponent, (2) attempts at the goal, (3) in-behind actions, (4) interceptions by the opponent, (5) loose ball receptions, (6) sprinting per minute by the opponent, (7) offers received by the opponent, (8) in-front opponent, (9) interceptions, and (10) total distance per minute. The top ten features for predicting losses were: (1) attempts at the goal by the opponent, (2) interceptions, (3) out to in actions, (4) possessions interrupted, (5) loose ball receptions by the opponent, (6) in front movements, (7) distance covered by the opponent, (8) in-behind actions by the opponent, (9) total distance, and (10) sprinting per minute. In conclusion, using an XGBoost model, this is the first study to successfully predict the match outcome for wins and losses from the FIFA Women's World Cup, but also explain which features significantly influence the prediction. This study may serve as a guide for practitioners regarding the use and application of XGBoost models in high performance.

This study aimed to investigate the effects of lower limb muscular asymmetry on the bilateral variations observed in high platform drop jumps, with a particular emphasis on the side-to-side differences in both the initial and secondary ground contacts during these jumps. Seventy-one students from the Physical Education department were selected to perform countermovement jumps. Participants were further classified into two groups, strength symmetry and strength asymmetry groups, based on the asymmetry strength index calculated from data collected via the force plates. Drop jumps were performed from three designated heights, i.e., 30 cm, 40 cm and 50 cm (DJ30, DJ40 and DJ50, respectively). The mixed design two-way ANOVA revealed notable differences between the stronger and weaker legs. Significant differences were observed in the timing of the peak vertical ground reaction force at the first ground contact of the DJ30 (p < 0.05) and in the shape factor of the push-off phase of the DJ40 (p < 0.05). The unilateral preference might lead to an increased risk of lower limb injuries. Prolonged training may exacerbate the degree of lower limb asymmetry. Potentially these findings can provide valuable suggestions for athletes and coaches in their training.