Biology of Sport最新文献

Metabolic syndrome (MetS) is a cluster of key clinical risk factors for cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), making it essential to address its components through targeted lifestyle interventions, such as exercise. This study aimed to investigate the impact of a combined training (CT) programme on adult women diagnosed with MetS. We hypothesized that participating in the programme would improve glucose and lipid metabolism, cardiovascular health, functional fitness abilities (FFA), body composition and anthropometrics in women with MetS. 105 inactive women were randomly assigned to either a CT (n=84) or control group (n=21). The CT group performed supervised combined aerobic and resistance training 3 days/week for 6 months. Blood glucose, haemoglobin A1c (HbA1c), insulin levels, homeostatic model assessment for insulin resistance (HOMA-IR), lipid profile, mean arterial pressure (MAP), resting (r-HR) and maximal heart rate (max-HR), body composition, anthropometrics and FFA were assessed before and after 3 and 6 months of training. After 3 months, the CT group showed significant improvements compared to controls in blood glucose (-36.4%), HbA1c (-22.8%), HOMA-IR (-12.5%), MAP (-16.9%), max-HR (-5.3%), r-HR (-20.4%), skeletal muscle to fat ratio (MFR) (+37.5%), and FFA (+200%). At 6 months, benefits were sustained or enhanced, particularly in glycaemic regulation, cardiovascular parameters, MFR, and FFA levels (p < 0.05). MFR was positively and linearly associated with changes in FFA, cardiovascular function, and glycometabolic markers. A 24-week CT programme significantly improved key MetS parameters in women, suggesting that it may be an effective non-pharmacological strategy to reduce CVD and T2DM risk.

The Integral Reactive Strength Index (IRSI) has recently been described in the literature as a new indicator that normalizes the reactive strength index based on fall height. This study aimed to compare the effects of a plyometric training program based on IRSI versus a traditional jump training program on spatiotemporal variables associated with the performance of national-level jumpers and sprinters. A randomized, crossover trial with three parallel groups was conducted. Twenty-seven male track and field athletes were divided into three groups. The G-RT1 group consisting of 9 participants, began the experiment with IRSI-based training as the load prescription criterion. The G-PT2 group consisting of 10 participants, started the experiment with traditional plyometric training, and the control group, G-CT3, consisting of 8 participants, continued its usual training. After 19 weeks, a two-way mixed analysis of variance for the G-RT1 group found a significant interaction and large effect sizes (ES) in the group-time relationship in the 60 m dash (p ≤ 0. 001; f = 101.2; η² = 0.089), and the standing triple jump (STJ) (p ≤ 0.001; f = 119.8; η² = 0.031). The G-PT2 also showed better results, but the ES was lower for the standing long jump (p ≤ 0.001; f = 52.7; η² = 0.045), and the STJ (p ≤ 0.001; f = 22.7; ηp² = 0.011). Meanwhile, the G-CT3 did not show significant improvement at the end of the program. It is concluded that the IRSI-based plyometric training program produces better results than the traditional program. The use of IRSI-based improves individualization, emphasizes high-intensity maintenance, and induces better results with less training volume.

Caffeine is widely utilized as an ergogenic aid in sports, yet its interaction with gut microbiota - a key modulator of metabolic and physiological processes - remains underexplored in athletic populations. This study aimed to investigate whether caffeine supplementation enhances the athletic performance of football players through gut microbiota regulation, thereby bridging the gap between caffeine's ergogenic effects and microbial mediation mechanisms. A 7-day randomized, double-blind, placebo-controlled trial was conducted with 32 male national-level football players. Participants were allocated to either a caffeine group (3 mg/kg body mass) or a placebo group. Performance assessments included agility tests, 30-m repeated sprints, technical dribbling tasks, and aerobic endurance evaluations. Fecal samples were analyzed via 16S rRNA sequencing to assess microbial diversity and composition. Structural equation modeling (SEM) was employed to evaluate the mediating role of gut microbiota. Caffeine supplementation significantly improved agility (p < 0.001, Cohen's d = 1.1), sprint performance (p = 0.007, d = 0.7), and technical execution (p = 0.003, d = 0.7) compared to placebo. Gut microbiota alpha diversity (Chao1, Shannon) increased in the caffeine group (p < 0.05), with enrichment of Prevotella, Bacteroides, and Veillonella. SEM revealed that 33.3% of caffeine's performance-enhancing effect was mediated by microbial diversity (β = 0.2, p = 0.01), while no direct caffeine-performance pathway was observed (p = 0.2). These findings demonstrate that caffeine enhances football-specific performance partially through gut microbiota modulation, emphasizing the microbiome's role in translating nutritional interventions into athletic gains. Future research should explore long-term microbial adaptations and personalized strategies combining caffeine with microbiome-targeted therapies.

This study investigated the relationship between acute and chronic training load metrics and non-contact muscle injuries in elite soccer players employing a novel statistical approach. A retrospective analysis was conducted during the 2020/21 season on 30 senior outfield players from an English Premier League club. Global Positioning System (GPS) technology monitored total distance, high-speed running (HSR) distance (5.5-7 m/s), sprint distance (> 7 m/s), and peak speed during training sessions and matches. A total of 42 injuries were documented, with an incidence of 8.94 injuries per 1000 hours, although only 12 non-contact muscle injuries were included in the analysis that occurred at 2.5 per 1000 hours of exposure. Acute (7-day) and chronic (28-day) training loads were examined, and data preprocessing addressed missing values and multicollinearity. To address class imbalance, the dataset was balanced using the Synthetic Minority Over-Sampling Technique (SMOTE) prior to logistic regression. Four significant predictors were retained: acute HSR (β = -0.175, p < 0.001), acute sprint distance (β = -0.613, p < 0.001), acute peak speed (β = 1.101, p < 0.001), and chronic total distance (β = 2.234, p < 0.001). The model demonstrated excellent discriminative ability with an AUC-ROC of 0.80. The results showed that higher acute volumes of HSR and sprint distance serve as protective factors against non-contact muscle injuries, whereas an increase in acute peak speed and chronic total distance significantly elevates injury risk. These findings underscore the importance of regular exposure to HSR to enhance injury resilience, while excessive load and peak speed may contribute to neuromuscular fatigue and overload.

This study aimed to assess the interchangeability between tracking variables derived from Global Positioning System (GPS) and those of an Optical Tracking System (OTS) in elite soccer players. Twenty-six male professional outfield soccer players (age 27 ± 4 years, height 182 ± 6.67 cm, mass 80.73 ± 7.74 kg) from an English Premier League (EPL) team formed the sample. Positional information was recorded using a GPS (10 Hz Apex, STATSports, Belfast, UK) and concomitantly by an OTS using six semi-automated HD cameras sampling at a frequency of 25 Hz (Second Spectrum, Los Angeles, USA). While differences exist for both total distance and high-speed running (HSR) between the GPS and OTS, the GPS was highly correlated with the OTS (r² > 0.99). The OTS displayed the highest values across all three examined variables. Total distance was 4% higher on average when utilising the OTS, while HSR and sprint distance were 12% and 18% higher respectively. Given its importance and the differences observed, regression equations should be utilised to align GPS and OTS data to allow practitioners to evaluate running performance and optimally prepare players for the demands of the game more effectively.

Women's football has experienced significant growth in sporting, economic, and social interest. However, there remains a shortage of studies examining key technical-tactical performance indicators in elite competitions. This research aimed to identify and quantify the influence of technical-tactical indicators on the effectiveness of offensive dynamic transitions in elite women's football, using a machine learning approach. To this end, 3,610 dynamic offensive transitions recorded across 35 matches from the final stages of the FIFA Women's World Cup 2023, UEFA Women's Euro, and UEFA Women's Champions League 2023/24 were analysed using an observational methodology. An ad hoc observation instrument, Transfootb, was developed to record teams' offensive behaviours, opponents' defensive responses, and the match context at the time of the offensive dynamic transition. A chi-square test was applied to identify associations between variables, followed by the training of a Random Forest model to predict transition outcomes. Additionally, ShAP values were computed and visualised to interpret the influence of the predictors. The model achieved an area under the curve of 0.78, with a recall of 18% and a specificity of 96%. The results indicate that the execution mode of offensive transitions and the match context significantly influence offensive success. Specifically, penetrating passes (≥ 3), counterattacks, and an opponent's low defensive positioning were the key predictors of successful offensive transitions. This study provides valuable scientific evidence to optimise strategic decision-making in dynamic offensive transitions in elite women's football. Furthermore, it highlights the potential of machine learning in analysing and predicting performance in sport-specific actions.

Research specifically investigating the distinct pharmacological and expectancy effects of caffeine using the deceptive placebo-balanced design remains scarce and with contradictory results. The aim of this study was to investigate the potential synergy between the pharmacological and expectancy effects of caffeine on exercise performance by using a placebo-balanced design. Sixteen physically trained athletes (11 males and 5 females; 21.7 ± 5.0 yr) participated in a study with a deceptive protocol including four randomized conditions: placebo informed-placebo ingested (control); placebo informed-caffeine ingested (pharmacological effect); caffeine informed-placebo ingested (expectancy effect); and caffeine informed-caffeine ingested (combined effects). Sixty minutes after ingestion, participants performed a countermovement jump, a standing triple jump, a medicine ball throw and a 20-m running sprint test. Relative to control, the pharmacological effect trial increased standing triple jump distance (+2.1% p = 0.032; Cohen's d= 0.59) and reduced 20-m sprint time (-0.8% p = 0.030; Cohen's d= 0.60). The combined effect trial reduced 20-m sprint time (-0.8% p = 0.021; Cohen's d= 0.64) in comparison to control. The expectancy effect trial did not modify performance in any of the performance tests with respect to control. When averaging the performance across all four tests, improvements relative to the control trial were +0.9%, +0.6% and +1.3% for pharmacological, expectancy and combined effects, respectively. The ingestion of caffeine, whether or not participants expected to receive it, improved exercise performance. This suggests that the primary driver of caffeine's ergogenic effect is its pharmacological action, with only a minor contribution from expectancy.

This study investigated pupil dynamics to establish a physiological index of mental processes associated with executive functioning, enabling objective evaluation of cognitive load during training to improve understanding of cognitive control in sport-specific contexts. Using video-based eye-tracking, we examined pupil and saccade responses in athletes (N = 40) and non-athletes (N = 40) performing an interleaved prosaccade and anti-saccade task. In this task, participants were instructed prior to target appearance to either make a reflexive saccade toward the target (pro-saccade) or inhibit that response and generate a voluntary saccade in the opposite direction (anti-saccade). Larger pupil dilation prior to target onset was observed during anti-saccade compared to pro-saccade preparation (p < 0.001, ηp² = 0.153). Athletes showed reduced pupil dilation compared to non-athletes (p < 0.05, ηp² = 0.049). In addition, trials with larger pupil dilation and smaller tonic pupil sizes were associated with faster saccade reaction times. Pupil dilation also positively correlated with saccade peak velocities but showed no association with saccade endpoint accuracy. These findings suggest that athletes may engage in more efficient motor preparation, as reflected by reduced pupil dilation. Moreover, phasic pupil dilation, indexing cognitive load, and tonic pupil size, associated with arousal level, both contributed to the control of saccade dynamics during goal-directed movements. Together, these results highlight the utility of pupil size as an objective and informative index for assessing both cognitive and arousal functions in sports science research.

To analyse the effects of four full squat (SQ) training programmes with different velocity loss (VL) thresholds (0%, 10%, 20%, and 40%) with blood flow restriction (BFR) implementation on muscle size, lower limb strength, and neuromuscular adaptations. Forty-six strength-trained men carried out an 8-week (16 sessions) SQ training programme with BFR that differed in the VL attained within the set: BFR 0% VL (BFR0, n = 11), BFR 10% VL (BFR10, n = 11), BFR 20% VL (BFR20, n = 11), and BFR 40% VL (BFR40, n = 13). The same inter-set recovery (2 minutes), sets (3), intensity (from 55% to 70% 1RM), and level of BFR (50% of arterial occlusion pressure) were established for all groups. Before and after the training intervention, the following tests were carried out: 1) vastus lateralis muscle size; 2) countermovement jump; 3) maximal isometric SQ test; 4) progressive loading SQ test; and 5) fatigue SQ test. Muscle hypertrophy increased as the VL increased ("group × time" interaction: p = 0.013). Only BFR20 significantly improved force production at various time intervals ("group × time" interactions: p ≤ 0.05). Moreover, effect sizes suggest that low-to-moderate VL thresholds maximize the improvements in SQ strength against different loads (BFR0: 0.47-1.75; BFR10: 0.61-1.96; BFR20: 0.71-2.18; BFR40: 0.38-1.53). In BFR contexts, low-to-moderate VL thresholds should be prescribed to optimize leg strength performance. Extremely low VL (i.e., 0%) seemed insufficient to maximize strength gains, while higher VL thresholds are more effective for promoting muscle hypertrophy but may somewhat compromise strength improvements.

The present study aimed to analyse the match running performance differences across 5-minute time intervals considering the players' participation in matches. A total of 381,194 individual match observations from professional soccer players competing in the First (n = 171,957) and Second (n = 209,237) Spanish soccer leagues over the 2022/23 season were collected. Soccer players were classified according to their participation in matches. Total distance (TD), very high-speed running (VHSR, 21-24 km × h^-1), and sprinting speed running distance (Sprint, > 24 km × h^-1) were analysed using a computerized tracking system (TRACAB, Chyronhego, New York, NY). Match data were divided into pre-defined 5-minute intervals. Linear mixed models were performed to analyse match running performance over the 5-minute intervals while controlling the influence of match participation. The main results showed a decrease in match running performance as the match time progressed, from the 55^th-60^th minute onward (p < .001), although match participation also had a significant influence. Specifically, substitute players covered significantly greater VHSR (p < .001) and Sprint distances (p < .001) than the rest of the players during their time of participation. These findings provide knowledge about the evolution of match running performance over match time. Finally, analysis of 5-minute intervals may help coaches understand the periods of matches where player substitutions are most effective.