Biology of Sport最新文献

This study investigated the etiology and recovery of knee extensor muscle fatigue following simulated basketball match-play. Thirteen adult male competitive basketball players (age: 25 ± 4 years, stature: 185 ± 9 cm, body mass: 86 ± 14 kg, body fat: 13 ± 4%) completed a simulated match-play (i.e., the Basketball Activity Simulation Protocol) consisting of standardized specific match-based basketball activities. Before (PRE) and immediately after (POST) the match-play, the neuromuscular function of the knee extensors was evaluated to determine the amount of muscle fatigue and its origin. Assessments were also repeated 24 h (POST24) and 48 h (POST48) after the match-play to evaluate muscle fatigue recovery. The main outcomes were maximal voluntary contraction (MVC) torque, voluntary activation estimated through superimposed stimuli, electrically-evoked twitch and doublet peak torque (PT), and the 10:100 Hz doublet ratio. The Total Quality Recovery (TQR) scale was used to assess the perceived recovery status at PRE, POST24 and POST48. Time-related changes (oneway repeated-measures ANOVA) were observed for MVC torque (main effect: P = 0.002, moderate; post hoc: POST < PRE, small), twitch and doublet PT (P < 0.001, strong; POST < PRE, POST24 and POST48, moderate-to-large) and 10:100 Hz doublet ratio (P < 0.001, strong; POST < PRE, POST24 and POST48, large; POST48 > PRE, moderate). Voluntary activation and TQR were not affected at the different time-points (P = 0.060 and P = 0.455, minimum, respectively). In conclusion, basketball match-play significantly reduced knee extensor MVC strength, with baseline levels being restored within 24 h. Muscle fatigue was accompanied by a significant pre-to-post match reduction of electrically-evoked torque responses, indicative of peripheral fatigue (and evidence of low-frequency fatigue), while no signs of central fatigue were noted.

The primary aim of this study was to determine whether the significant improvements in 100 m-meter sprint times over the past 40 years are the result of an overall enhancement in performance among all elite sprinters, or are mainly driven by the sporadic emergence of exceptionally talented individuals. Additionally, we compared the average age of the semifinalists with that of the champion. To explore this broader research question, we compared the average performance times and ages of World Championship semifinalists with those of the champions over successive 2-year intervals. This approach allowed us to ascertain whether there has been a consistent improvement in average performances among elite sprinters or whether progress is mainly due to extraordinary athletes who occasionally set new records. By analyzing these patterns, we aimed to understand the underlying factors contributing to advancements in sprint performance and to assess whether these improvements are widespread or concentrated among a few exceptional individuals. Finally, we analyzed the relationship between age and 100 m-meter performance and predicted the results of semifinalists and winners at the Athletics World Championships in 2025 and 2027, for both men and women. The results obtained suggest that progress in sprinting, in both sexes, depends on the emergence of exceptionally talented individuals who set new world records or achieve world-leading times during the main competitions of the season. These exceptionally talented athletes have improved the winning times in the main 100 m-meter competitions, while the average times of semifinalists at the Athletics World Championships have remained relatively constant, ranging between 10.40 and 10.50 seconds over the analyzed 40-year period.

The Australian Football League Women's (AFLW) is the premier national women's competition in Australian Rules football. The aim of this exploratory study was to investigate the neuromuscular fatigue response to match-play and the external load correlates of this response in AFLW. Players (n = 22) wore a 10 Hz GNSS device and completed immediately pre- and post-match countermovement jumps (CMJ) on dual force plates for each match in the 2022 AFLW competitive season. Concentric, eccentric, and composite CMJ variables were selected a priori based on previously established validity, reliability, and sensitivity to detect neuromuscular fatigue. The change in each variable from pre- to post-match was analysed using linear mixed effect models and rank bi-serial correlation (r _bs) effect size statistic. Linear mixed models were also constructed to examine the relationship between external load variables and the change in CMJ metrics. Each player was included as a random effect in these models. Match-play resulted in large negative effects to eccentric mean force, eccentric peak force, and force at zero velocity (all r _bs = 0.808 - 0.813), concentric impulse (r _bs = 0.646), flight time:contraction time (r _bs = 0.528), and jump height (r _bs = 0.491). Modelling identified high-speed running distance, repeated highintensity effort bouts, and acceleration load as significant (p < 0.05) correlates of the change in CMJ variables from pre- to post-match. The variance explained in these models was low (Conditional R² = 0.128-0.186). Identified CMJ variables may be important to monitor fluctuations in neuromuscular fatigue, whilst external load variables may be useful in examining neuromuscular fatigue correlates in AFLW. Given the exploratory nature of this study, further research is necessary to explore these findings in a hypothesis driven framework.

Despite the growing interest in research on women's football, few approaches have analysed the primary performance indicator in football, which is the goal. This study describes the goal scoring patterns and explores technical-tactical behaviours associated with the scorer location in the 2022 UEFA Women's European Championship. The sample was made up of all the 95 goals scored by the 16 teams in the 31 games played. Three UEFA Pro coaches designed an ad hoc observational instrument, and one observer coded the data after a training process, ensuring intraobserver reliability. Descriptive and inferential analyses were conducted. Assistant location was significantly associated with scorer location (p < 0.005, ES = 0.930). The highest percentage of assists came from the lateral corridors outside the penalty area (23.2%). The most frequent shot zones being the projection from the goal line to the penalty spot (48.2%). It is also remarkable that half of the goals came from an aerial ball (51.2%), the leg (66.3%) and a first contact shot (69.8%) being the most common finishing situations. A similar distribution was noted concerning the areas where shots crossed the goal line (40.0% near post vs 41.3% far post). Our findings reveal goal-scoring patterns in elite women's football to consider in the coaching process, for instance, to design drills to promote the replication of the most common finishing situations (aerial, leg and first contact) and contexts where most recurrent assisting and shooting zones could be considered. Raising awareness among coaches and players about these practical aspects can improve goal-scoring situations.

We compared the physical and physiological responses of young soccer players of different ages U13 (Under 13 years), U15, and U17 and competitive levels (elite and sub-elite) during fixed-pitch size smallsided games (SSGs) performed under different formats. In a cross-sectional design, seventy-two male players (12 players in each group) performed 3-a-side and 4-a-side SSGs with a fixed-pitch size (40 × 20 m). The total distance covered (TD), peak velocity (Vpeak), the distances covered at different running speed zones (0 to < 7.0, 7.0 to < 14.0, 14.0 to < 18.0, and ≥ 18.0 km.h^-1), peak heart rate (HRpeak), HRmean, expressed as percentage of the theoretical HR_maxTheo, and blood lactate concentration post-SSGs (BLa) were recorded. Players in the 3-a-side SSGs covered more TD, distances covered at different speeds and Vpeak than those of the 4-a-side SSGs across all age categories of both competitive levels (p < 0.05). The 3-a-side SSGs induced higher BLa in all elite groups (p < 0.05), and U13-sub-elite players (p=0.004). HR_peak(%HR_maxTheo) and HR_mean(%HR_maxTheo) were greater in the 4-a-side SSGs than the 3-a-side SSGs in most age categories of both competitive levels (p < 0.05). In the zone-3, the U13- and U15-elite covered more distance than U17 in both formats. In both formats, elite players covered larger TD and distances at zone-1 and zone-4 sub-elite players (p < 0.05). BLa was higher in U17-sub-elite compared to their elite counterparts in the 4-a-side SSGs. Our study shows that 3-a-side SSGs are physically more demanding than 4-a-side, especially for elite players. Tailoring training to age and competitive level is crucial for optimising player development.

Large Language Models (LLMs) are increasingly utilized in various domains, including the generation of training plans. However, the reproducibility and quality of training plans produced by different LLMs have not been studied extensively. This study aims to: i) investigate and compare the quality of muscle hypertrophy-related resistance training (RT) plans generated by Google Gemini (GG) and GPT-4, and ii) the reproducibility of the RT plans when the same prompts are provided multiple times concomitantly. Two distinct prompts were used, one providing little information about the training plan requirements and the other providing detailed information. These prompts were input into GG and GPT-4 by two different individuals, resulting in the generation of eight RT plans. These plans were evaluated by 12 coaching experts using a 5-point Likert scale, based on quality criteria derived from the literature. The results indicated a high degree of reproducibility, as indicated by coaching expert evaluation, when the same distinct prompts were provided multiple times to the LLMs of interest, with 27 out of 28 items showing no differences (p > 0.05). Overall, GPT-4 was rated higher on several aspects of RT quality criteria (p = 0.000-0.043). Additionally, compared to little information, higher information density within the prompts resulted in higher rated RT quality (p = 0.000-0.037). Our findings show that RT plans can be generated reproducibly with the same quality when using the same prompts. Furthermore, quality improves with more detailed input, and GPT-4 outperformed GG in generating higherquality plans. These results suggest that detailed information input is crucial for LLM performance.

Reconstruction of the anterior cruciate ligament (ACL) is associated with degenerative changes during the return-to-play (RTP) process. Infrared thermography, due to its usefulness in monitoring the state of tissues, could help establish physiological criteria for monitoring the knee joint. The aim of the study was to describe normative skin temperature (Tsk) asymmetry of the knee region of interest (knee ROI) from football players during the ACL RTP process. Thirty professional and semi-professional football players, both male and female, from three different European leagues (age: 26.84 ± 3.46 years; height: 1.83 ± 0.22 m; weight: 75.38 ± 5.92 kg) were evaluated using thermography during their RTP process. A linear mixed model was then developed in which Tsk asymmetry was the dependent variable. Sex and Day were included as predictor variables with fixed effects. Athlete was included as a random effect with (Model 1 and Model 2) and without (Model 3) interaction with Day. Model 2 was fitted with a random intercept and random independent slopes, and Model 3 was fitted with a random intercept and random dependent slopes. The results showed the estimates of the model in which both predictor variables were significant. The asymmetry decreased during the days after surgery (-0.01 per day after surgery). The results might help to establish an objective criterion based on infrared thermography for monitoring the rehabilitation stages in the RTP of football players during one year of evolution. The assessment of the thermal asymmetries of the knee ROI during the RTP established a Tsk progression criterion. Medical and technical staff could implement an infrared thermography tool for knee monitoring between RTP stages.

Late-stage rehabilitation interventions after an anterior cruciate ligament (ACL) reconstruction are under-researched, inter alia regarding potential differences in rehabilitation effects between autograft types. This study determined the effectiveness of a specific, late-stage rehabilitation to usual care after ACL reconstructions in patients with a quadriceps versus such with a hamstring tendon autograft. In this multicentre case-control intervention study, participants aged 18-35 years were included at the end of their formal rehabilitation (mean 8.1 months) after ACL reconstruction. Twenty-four cases with an arthroscopically assisted, anatomic ipsilateral quadriceps femoris tendon autograft and two numerically equal hamstring tendon reconstructed propensity score-matched groups were compared. Matching variables were gender, age, Tegner activity scale, plus, once, the time since reconstruction and once the functional capacity at intervention onset. All participants performed a 5-month performance enhancing intervention. All outcomes were measured once a month. Self-reported outcomes such as knee function (The Knee injury and Osteoarthritis Outcome Score (KOOS) Sport as the main self-reported outcome) were followed by a series of hop and jump tests. The front hops for distance (outcome: hopping distance) was the primary outcomes of the study. Linear mixed models were calculated using change scores. All participants were analysed. No group*time interaction effect could be identified in the two main outcomes KOOS SPORT and front hop for distance. Furthermore, with the exception of the self-reported all-day function, no outcome displayed any between-group differences in the trainability, either. The return-to-sport success took a mean time of 3.8 months after study commencement; the success rates ranged between 80% and 83% and were not different between groups. Being reconstructed with a hamstrings or with a quadriceps tendon autograft had no impact on the late-stage rehabilitation effects after an ACL rupture. Both graft choices enable comparably favourable functional outcomes and return-to-sport success rates. Conversely, no recommendation can be derived with regard to the selection of either a hamstring or a quadriceps autograft type. The decision must be undertaken individually and based on other factors.

Maximal strength is considered a fundamental aspect of athletic performance across a wide range of sports and is also needed for a range of activities of daily life. Yet, compared to males there are fewer publications examining females, with most showing similar coefficients of correlation between dynamic strength and different athletic performances. In both, males and females, results are biased by mostly small sample sizes (sample bias) leading to a fluctuation around the true correlation coefficient of the entire population. This crosssectional analysis involving 1544 participants employed multivariate and correlative analyses to clarify the importance of maximum strength in the parallel back squats on the jump performance controlling for variables such as type of sport, sex, age, and performance level. The analysis revealed two principal components that reflect distinct types of variability within the dataset: the first, primarily associated with performance capabilities, accounts for 58.45% of the variance, while the second, emphasizing demographic differences, accounts for a considerably lower variance of 25.08%. The correlation analyses in this study identified maximal strength as a significant factor influencing jumping performance, accounting for 48-53% of the variance in jump height. The analysis presents a saturation curve, with potential diminishing returns at higher strength levels. Age and sex had little to no effect on overall correlation coefficients. The overall correlation coefficients and the analyses for the subgroups (by sport and performance level) can differ considerably, which can be explained (mathematically) by the artificial formation of clusters, homogeneous subject groups, or small sample sizes.

This study aimed to examine the influence of different scores in the first and second half on running and explosive-based performance of elite male soccer players. Thirty-three professional players from one English Premier League team participated in the study across two consecutive seasons, 2021/22 and 2022/23. Matches were divided into half (first versus second) and nine phases; WIN-WIN; WIN-DRAW; WIN-LOSS; DRAW-WIN; DRAW-DRAW; DRAW-LOSS; LOSS-WIN; LOSS-DRAW; and LOSS-LOSS. Match physical data were monitored using an 18 Hz Global Positioning System. There was a main effect for half for all variables (p < 0.001-0.008; η² = 0.004-0.028), with distances covered per minute and number of explosive actions per minute greater in the first-half than second-half (d = 0.144-0.374). There was an interaction effect between half and phase for m/min, high-speed running per min, high metabolic load distance (HMLD) per min, HML efforts/min, and accelerations/min (p < 0.001-0.012; η² = 0.010-0.015). There was a reduction between first-half and second-half performance during WIN-WIN, WIN-DRAW, DRAW-WIN, DRAW-DRAW, LOSE-WIN, and LOSE-LOSE for m/min (p < 0.001; d = 0.435-0.714), HMLD/min (p < 0.001-0.004; d = 0.334-0.605), and HML efforts/min (p < 0.001; d = 0.408-0.611). In conclusion, our findings emphasise the importance of considering both match half and phase when analysing players' physical performance to support the prescription of tailored training programs and tactical strategies to optimise performance across different match situations.