Effects of chronic static stretching interventions on jumping and sprinting performance-a systematic review with multilevel meta-analysis.

When improving athletic performance in sports with high-speed strength demands such as soccer, basketball, or track and field, the most common training method might be resistance training and plyometrics. Since a link between strength capacity and speed strength exists and recently published literature suggested chronic stretching routines may enhance maximum strength and hypertrophy, this review was performed to explore potential benefits on athletic performance. Based on current literature, a beneficial effect of static stretching on jumping and sprinting performance was hypothesized. A systematic literature search was conducted using PubMed, Web of Science and Google scholar. In general, 14 studies revealed 29 effect sizes (ES) (20 for jumping, nine for sprinting). Subgroup analyses for jump performance were conducted for short- long- and no stretch shortening cycle trials. Qualitative evaluation was supplemented by performing a multilevel meta-analysis via R (Package: metafor). Significant positive results were documented in six out of 20 jump tests and in six out of nine sprint tests, while two studies reported negative adaptations. Quantitative data analyses indicated a positive but trivial magnitude of change on jumping performance (ES:0.16, p = 0.04), while all subgroup analyses did not support a positive effect (p = 0.09-0.44). No significant influence of static stretching on sprint performance was obtained (p = 0.08). Stretching does not seem to induce a sufficient stimulus to meaningfully enhance jumping and sprinting performance, which could possibly attributed to small weekly training volumes or lack of intensity.

Effectiveness of motor imagery on sports performance in football players: A randomised control trial.

Background: Nowadays, the development of training programs for speed, agility and reaction time responses in football players is increasing widely. Motor imagery is a new method that uses collateral with physical training. However, there is still a scarcity of evidence concerning the addition of motor imagery protocol to routine training programs. Objective: The main objective was to compare speed, agility and reaction time after motor imagery training in university athletes and amateur athletes who received and did not receive motor imagery training for 2 weeks. Methods: Participants were divided into 4 subgroups as follows: university athlete group with motor imagery training and control group, amateur athlete group with motor imagery training and control group. This study collected the training effects of speed, agility and reaction time. The Wilcoxon signed-rank test and the Mann-Whitney U test were selected to analyse the differences within and between groups, respectively. Results: The result presented positive changes in all variables after training sessions for 2 weeks in all groups. Speed at 20 m, agility, and reaction time were found to be significantly different after motor imagery training in both university athletes and amateur athletes. Conclusion: This finding demonstrated that the addition of the motor imagery training along with routine physical training promotes physical performance in athletes at all experience levels. In further studies, the retention effect after practice should be considered.

Beyond the Jump: A Scoping Review of External Training Load Metrics in Volleyball.

CONTEXT: Volleyball is a complex sport involving multifaceted movements and high-velocity actions, leading to diverse external training loads (ETLs) that have profound implications for player performance and injury risk. OBJECTIVE: To provide a comprehensive overview of the measurement of ETL in volleyball, identify gaps in current understanding, and offer valuable insights for stakeholders in the field. DATA SOURCES: The literature search was conducted across the following electronic databases: PubMed/Medline, Scopus, Web of Science, and SPORTDiscus. STUDY SELECTION: Studies were selected based on their relevance to the measurement of ETL in volleyball. STUDY DESIGN: A scoping review methodology was chosen to map and summarize the broad body of literature related to ETL measurement in volleyball. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Data related to ETL measurements in volleyball were extracted and analyzed from the selected studies, focusing on metrics utilized, player positions examined, and technologies employed. RESULTS: A total of 18 studies related to ETL in volleyball were identified and examined for this review. Despite the importance of sagittal plane movements in volleyball, the review identified a substantial research gap regarding ETL measurements beyond this plane, as well as a lack of focus on the unique demands of different player positions like the liberos. The use of technologies such as inertial measurement units was prevalent, but more comprehensive measurement methods are needed. CONCLUSION: There is a critical need for diversified ETL metrics in volleyball, extending beyond the conventional sagittal plane measurements. The findings highlight a substantial research gap in addressing the unique demands of different player positions, notably the liberos. This study underscores the importance of incorporating multiplanar movement data, player-specific roles, and advanced measurement technologies to develop more tailored training programs and injury prevention strategies.

Optimal homeostatic stress to maximize the homogeneity of adaptations to interval interventions in soccer players.

This study examined the uniformity of adaptations in cardiorespiratory fitness and bio-motor abilities by analyzing individual responses to measures representing the mentioned qualities. Twenty-four male well-trained soccer players (Age = 26 ± 4 years; stature = 181 ± 3.8; Weight = 84 ± 6.1) were randomized to two groups performing short sprint interval training [sSIT (3 sets of 10 × 4 s all-out sprints with 20 s of recovery between efforts and 3 min of rest intervals between sets)] or a time-matched small-sided game [SSG (3 sets of 3 v 3 efforts in a 20 × 15 m area with 3 min of relief in-between)]. Before and after the 6-week training period, aerobic fitness indices, cardiac hemodynamics, and anaerobic power were assessed through a graded exercise test utilizing a gas collection system, noninvasive impedance cardiography, and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring linear speed, change of direction, and jumping ability. Comparing inter-individual variability in the adaptive changes by analyzing residuals in individual adaptations indicated that sSIT induces more uniform changes in the first and second ventilatory threshold (VT1 & VT2), stroke volume, and peak power output across team members than SSG. SSG also yielded lower proportions of responders in V˙O2⁡max, VT1, VT2, peak, and average power output compared to sSIT. Additionally, the coefficient of variation in mean group changes in measures of aerobic fitness and bio-motor abilities in response to sSIT were lower than in SSG. Short sprint interval training induces more homogenized adaptations in measures of cardiorespiratory fitness and anaerobic power than small-sided games across team members.

Polyphenol supplementation boosts aerobic endurance in athletes: systematic review.

In recent years, an increasing trend has been observed in the consumption of specific polyphenols, such as flavonoids and phenolic acids, derived from green tea, berries, and other similar sources. These compounds are believed to alleviate oxidative stress and inflammation resulting from exercise, potentially enhancing athletic performance. This systematic review critically examines the role of polyphenol supplementation in improving aerobic endurance among athletes and individuals with regular exercise habits. The review involved a thorough search of major literature databases, including PubMed, Web of Science, SCOPUS, SPORTDiscus, and Embase, covering re-search up to the year 2023. Out of 491 initially identified articles, 11 met the strict inclusion criteria for this review. These studies specifically focused on the incorporation of polyphenols or polyphenol-containing complexes in their experimental design, assessing their impact on aerobic endurance. The methodology adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the risk of bias was evaluated using the Cochrane bias risk assessment tool. While this review suggests that polyphenol supplementation might enhance certain aspects of aerobic endurance and promote fat oxidation, it is important to interpret these findings with caution, considering the limited number of studies available. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023453321.

Does the sequence of plyometric and dynamic stretching exercises influence subsequent sprint performance? A randomized crossover intervention study.

The objectives of this study were to evaluate the acute effects of the sequence order of drop jumps (DJ) and dynamic stretching (DS) on sprinting performances in competitive athletes and to investigate the relationships between post-activation performance enhancement (PAPE) in sprint performance and lower limb power. Thirteen male jumpers and sprinters participated in this study (19 ± 2 years; 177 ± 7 cm; 71.7 ± 5.6 kg). Through a randomized crossover design, the athletes were exposed to three different conditions after a standardized warm-up: DS+DJ, DJ+DS, and control. Sprinting performance over 40 m was analysed with consideration of initial (0 to 20 m) and final acceleration (20 to 40 m) phases. The effect of intervention was examined by two-way repeated-measures of ANOVA. Pearson's correlation test was used to determine the association between PAPE during sprinting and jump performance. There was no effect of any factor on 40-m sprint performance. Meanwhile, the performance at 20-40 m was higher after the DS+DJ condition when compared to baseline (8.79 ± 0.43 vs. 8.91 ± 0.35 m/s; p = 0.015). However, the initial acceleration was worsened in the DJ+DS condition when compared to baseline (6.26 ± 0.25 vs. 6.22 ± 0.26 m/s; p = 0.002). There was a negative correlation between CMJ height and the improvement in final acceleration (r = -0.741; p = 0.004). The use of DS prior to DJ is an effective strategy to improve performance in the final acceleration phase (20-40 m). The athletes with lower levels of lower limb power benefited the most from this PAPE strategy.

Testing variations between starters and substitute players in terms of total distance, high-speed running, and sprinting distance: a descriptive study on professional male soccer players.

The purpose of this study was three-fold: (i) to compare total distance, high-speed running (HSR) distance, and sprint distance covered per 5-minute epoch by players acting as both starters and substitutes; (ii) to compare the locomotor demands between the moments the players entered the match (45-60, 60-75 and 75-90 minutes); and (iii) to compare the locomotor demands of the players between the variations of the within- and between-playing positions. Twenty-one male professional soccer players competing in the Professional Premier League of one of the European countries were observed over sixteen official matches. The players were monitored during all matches using a Global Navigation Satellite System. The measures collected were total distance (TD; m), distance in HSR, sprint distance, HSR, and sprint counts. Considering the comparisons between the splits over the second half of match play, a significant difference between the starters and the substitutes was observed only for sprint distance in the 90-95 minute split (Z = -2.023; p = 0.043). Moreover, no substantial differences were found between the moment the substitute player entered the match regarding total distance (H = 2.650; p = 0.266), HSR distance (H = 1.738; p = 0.419), and sprint distance (H = 0.048; p = 0.976). However, the comparison of between-playing positions revealed considerable differences in total distance (H = 29.246; p < 0.001), and HSR distance (H = 12.153; p = 0.002) covered by the players acting as starters. In contrast, for substitute players, such differences were reported in HSR distance (H = 27.892; p < 0.001) and sprint distance (H = 15.879; p < 0.001). In conclusion, this study suggests that acting as a starter or a substitute does not significantly affect the intensity of effort except during the last periods of match play. However, the contextual factor of performing in a specific playing position plays a significant role both for starters and substitutes.

Fasting reduces satiety and increases hunger but does not affect the performance in resistance training.

Intermittent fasting (IF) has been suggested to reduce body fat percentage and improve non-communicable chronic diseases. However, little is known about resistance training (RT) and the subjective perception of hunger under fasted conditions. This study aimed to examine the effects of overnight fasting (12 h or 16 h fasting) on the maximum voluntary isometric contraction (MVIC) and countermovement jump (CMJ) performance in resistance-trained young male adults. In RT sessions, the maximum number of repetitions (MNR) and the total volume load (TVL) were evaluated in the back squat and leg press 45°. The volunteers performed all tests and the RT session in 3 different conditions: fed state, 12 and 16 hours of IF. The subjective perception of hunger was applied through an adapted visual analogue scale (adVAS). The results showed that strength and power variables did not change significantly: MVIC (p = 0.960), CMJ (p = 0.986), MNR back squat (p = 0.856), MNR leg press 45° (p = 0.998), TVL (p = 0.954). However, hunger was significantly greater after the 16-hour fasting (p = 0.001) compared to 12 hours of fasting and the fed state. Also, the desire to eat was greater after 16 hours (p = 0.001) compared to 12 hours of fasting and the fed state. This study indicates that IF for 12 or 16 hours does not significantly impair strength and power, but the longer the fasting duration, the greater are the hunger and desire to eat.

Effects of changing the head coach on soccer team's performance: A systematic review.

The aim of this review was to identify and synthesise the most significant literature addressing the effects of changing the HC on soccer team's performance, identifying the most frequently researched outcomes and characterizing their methodologies. A systematic review of PubMed, Scopus, Web of Science and SPORTDiscus databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA, 2020) guidelines. The following keywords and synonyms were entered in various combinations in the title, abstract or keywords: "football*" OR soccer AND "coach*" OR "manager*" AND "replacement" OR "turnover" OR "substitution*" OR "change". Solely original articles written in English that contained data about the effects of the change in the HC on performance in professional male soccer were included. A total of 94 titles were identified, of which 24 met the eligibility criteria. The quality of the studies was considered excellent. The most common topic of analysis was the effects of the HC on match outcomes (i.e., win, draw, loss, points won, goals average). Some studies suggest that the HCs dismissal has small but positive impacts on a team's short-term performance, while other findings suggest that little-to-no impact is observed following HC departure. The dismissal of the HC does not guarantee increase success of an underperforming team. Some studies suggest that hiring an appropriate coach could positively affect match performance in the short-term. Due to limited variations in study designs, further research is needed before robust conclusions can be drawn.

Household food insecurity among child and adolescent athletics practitioners: A cross-sectional, descriptive, and exploratory study.

OBJECTIVE: The aim of the study was to explore the prevalence of food insecurity among child and adolescent athletics practitioners and to investigate factors associated with exercise performance, dietary habits, body composition, sleep, and socioeconomic status based on food security status. METHODS: This was a cross-sectional, descriptive, and exploratory study conducted in Campinas, São Paulo, Brazil, between June and July 2023. The convenience sample included children and adolescents (7-17 y old) of both sexes. We evaluated exercise performance, household food insecurity (HFI), dietary-related parameters, and other body composition, lifestyle, and social-related variables. Exercise performance was assessed using the counter movement jump (CMJ), squat jump (SJ), horizontal long jump (HLJ), 50-m sprint test (50-m ST) and throwing strength test (TST). The assessment of HFI was conducted using the food insecurity experience scale (FIES). Comparisons and associations were investigated based on food security status. RESULTS: The total sample size was comprised of 138 children (n = 42; 30.4%) and adolescents (n = 96; 69.6%). We found an association between food security status and sex (X2(138,1) = 4.42; P = 0.036). SJ was higher in the food security group than in the HFI group (t(117) = 2.112; P = 0.037; ES = 0.39). Sleep- and dietary-related factors did not differ between the groups. CONCLUSIONS: In summary, the prevalence of HFI among child and adolescent athletics participants was approximately 40%. Regarding exercise performance, SJ was better in the food security group than in the HFI group. Concerning dietary-related data, the HFI group had a lower number of meals per day than the food security group, and other dietary data did not differ between the groups. Body composition and sleep-related parameters were similar between the groups.

Inconsistencies in the perceived impact of the menstrual cycle on sport performance and in the prevalence of menstrual cycle symptoms: A scoping review of the literature.

OBJECTIVES: This scoping review aimed to summarize the findings of studies regarding the perceived impact of the menstrual cycle on athletic performance, as well as the prevalence of negative menstrual cycle symptoms. DESIGN: Scoping review. METHODS: Three databases were searched and the Preferred Reporting Items for Systematic reviews and Meta Analyses extension for Scoping Reviews (PRISMA-ScR) was used as guidance. RESULTS: A total of 39 studies were included in the final analysis. Between 2.8 and 100 % of athletes reported their performance being negatively impacted by their menstrual cycle, and the main reason was the occurrence of menstrual cycle symptoms. Additionally, a large variability in the prevalence of menstrual cycle symptoms was reported in the different studies mainly due to methodological differences and recall biases. CONCLUSIONS: Similarly, as to what has been reported in reviews summarizing performance outcomes during different menstrual cycle phases, this review highlights the high degree of variability between how athletes perceive to be impacted by their menstrual/hormonal contraceptive cycle. REGISTRATION: The protocol of this scoping review was registered at the Open Science Framework on 14 September 2023 (osf.io/efu9x).

Effects of post-exercise cold-water immersion on performance and perceptive outcomes of competitive adolescent swimmers.

PURPOSE: To evaluate the effects of repeated use of cold-water immersion (CWI) during a training week on performance and perceptive outcomes in competitive adolescent swimmers. METHODS: This randomized-crossover study included 20 athletes, who received each intervention [CWI (14 ± 1 °C), thermoneutral water immersion (TWI) (27 ± 1 °C) as placebo, and passive recovery (PAS)] three times a week between the land-based resistance training and swim training. The interventions were performed in a randomized order with a 1-week wash-out period. We tested athletes before and after each intervention week regarding swim (100 m freestyle sprints) and functional performance (flexibility, upper and lower body power, and shoulder proprioception). We monitored athlete's perceptions (well-being, heaviness, tiredness, discomfort and pain) during testing sessions using a 5-item questionnaire. Athlete preferences regarding the interventions were assessed at the end of the study. We used generalized linear mixed models and generalized estimating equations for continuous and categorical variables, respectively (intervention x time). RESULTS: We found a time effect for swim performance (p = .01) in which, regardless the intervention, all athletes improved sprint time at post-intervention compared to baseline. There was an intervention effect for pain (p = .04) and tiredness (p = .04), but with no significant post-hoc comparisons. We found no significant effects for other outcomes. All athletes reported a preference for CWI or TWI in relation to PAS. CONCLUSION: The repeated use of CWI throughout a training week did not impact functional or swim performance outcomes of competitive adolescent swimmers. Perceptive outcomes were also similar across interventions; however, athletes indicated a preference for both CWI and TWI.

Application of mobility training methods in sporting populations: A systematic review of performance adaptations.

This systematic review investigates influences of mobility training in sporting populations on performance outcomes. The search strategy involved Embase, MEDLINE Complete, Sports Discus and manual search from inception to March 2022. Mobility training studies with a minimum three-week, or 10-session duration in healthy sporting populations of any age were included. Twenty-two studies comprising predominantly young adult or junior athletes were analysed from 319 retrieved articles. Performance outcomes were strength, speed, change of direction, jumping, balance, and sport-specific skills. Fifteen studies randomized participants with only four indicating systematic allocation concealment and blinding of outcomes assessors in only one study. In 20 of 22 studies mobility training was of some benefit or helped to maintain sports performance to a larger degree than control conditions. Control conditions, which were generally no activity conditions, were primarily non-significant. The majority of evidence suggests that a range of mobility training methods may improve key sports performance variables or are unlikely to impair performance over time. Therefore, coaches can consider the potential benefits of including comprehensive mobility programmes with minimal risk of impairing performance. Higher-quality studies in homogenous populations are necessary to confirm performance changes.

Optimizing Short-Term Maximal Exercise Performance: The Superior Efficacy of a 6 mg/kg Caffeine Dose over 3 or 9 mg/kg in Young Female Team-Sports Athletes.

Caffeine (CAF) is among the most extensively researched dietary supplements worldwide. However, little is known about the relationship between dosage and performance enhancement, particularly in female athletes. This study aimed to explore the effects of three different CAF dosages (3 mg·kg-1, 6 mg·kg-1, and 9 mg·kg-1) on high-intensity exercise and the prevalence of undesirable side effects related to these doses among female team-sports athletes. All participants (n = 16; age: 16.9 ± 0.6 y; height: 1.64 ± 0.1 m; BMI: 21.6 ± 1.5 kg·m-2) were mild CAF consumers. This study had a randomized, crossover, double-blind design in which each athlete performed four experimental sessions after ingesting either a placebo (PLAC), 3 mg·kg-1 CAF (CAF-3), 6 mg·kg-1 CAF (CAF-6), or 9 mg·kg-1 of CAF (CAF-9), with an in-between washout period of at least 72 h. In each experimental session, 60 min after ingesting the capsules, participants underwent a countermovement jumps test (CMJ), modified agility t-test (MATT), repeated sprint ability (RSA) test, and a rating of perceived exertion (RPE) and completed the CAF side effects questionnaire. Our findings revealed that in comparison to the PLAC condition, the MATT, RSAmean, and RSAbest performances were significantly greater only under the CAF-6 and CAF-9 conditions. Although the RPE scores remained unchanged, CMJ performance improved under all CAF conditions. All the performance outcomes were better for the CAF-6 and CAF-9 conditions than for the CAF-3 condition. Notably, no significant difference between the CAF-6 and CAF-9 conditions was observed for any of these parameters despite the highest incidence of side effects being noted for the CAF-9 condition. In summary, our findings highlight the recommendation for a moderate CAF dosage of 6 mg·kg-1 rather than 3 or 9 mg·kg-1 to enhance various aspects of short-term maximal performance in mild-CAF-consumer female team-sports athletes while mitigating the occurrence of adverse CAF side effects.

Gender-Specific Effects of Short Sprint Interval Training on Aerobic and Anaerobic Capacities in Basketball Players: A Randomized Controlled Trial.

This study compared the effects of a 6-week short sprint interval training (sSIT) on male and female basketball players' bio-motor abilities, aerobic fitness, and anaerobic power. Using a randomized controlled trial design, 40 basketball players of similar training backgrounds were randomly assigned to two training groups of females (n = 10) and males (n = 10) or two control groups of females and males (each of 10). The training groups performed 3 sets of 10 × 5-second all-out interval running, with a 1:3 work-to-recovery ratio, and a 3-minute rest between sets. The players were evaluated for bio-motor abilities, including muscular power assessed through the vertical jump, agility measured using a T-test and Illinois change of direction (COD) test, and maximal sprint speed measured by a 20-meter sprint test. Also, aerobic fitness was assessed by evaluating maximum oxygen consumption (V̇O2max) through the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR 1) test before and after the 6-week training period. After the intervention, both training groups (females and males) demonstrated significant improvements in vertical jump (effect size [ES] = 1.29, 1.06, respectively), peak power output (ES = 1.27, 1.39), T-test (ES = -0.56, -0.58), Illinois COD test (ES = -0.88, -1.1), 20-m sprint (ES = -1.09, -0.55), Yo-Yo IR1 performance (ES = 2.18, 2.20), and V̇O2max (ES = 2.28, 1.75). Gender did not exhibit any significant impact on the extent of changes observed over time. The results of this study suggest that adaptations in aerobic fitness and bio-motor abilities measured in this experiment in response to sSIT are similar across genders, and gender differences should not be a major concern when implementing sSIT in basketball players.

Effects of small-sided games training programs on physiological and physical adaptations of youth basketball players: A systematic review.

The primary objective of this study was to systematically investigate the physiological and physical fitness adaptations resulting from small-sided games (SSGs) training programs in basketball players competing at youth competitive levels, as compared to other training approaches and/or control groups. To achieve this, we conducted a literature search on PubMed, Scopus, SPORTDiscus, and Web of Science, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. From the initial 626 studies retrieved, five were considered eligible for the current study. Among the five included articles, four conducted comparisons between the effects of SSGs and running-based high-intensity interval training. Regarding this, the four studies revealed a significant improvement in the final velocity during the 30-15 Intermittent Fitness Test, ranging from 4.07% to 7.29% following SSG-based interventions. This improvement was not significantly different from the comparator group. Additionally, two studies indicated that the SSGs group showed a significant advantage in change-of-direction time, with improvements ranging from -2.11% to 6.69% after interventions, and these results were not significantly different from the comparator group. However, the effects on repeated sprint ability yielded contradictory findings; two studies reported significant improvements ranging from -5.00% to -2.16%, while two others did not show significant effects following SSGs-based interventions. Similarly, in the linear sprint, the results of SSGs-based interventions were inconsistent. In summary, based on the available research, it can be concluded that SSG-based training is effective in significantly enhancing aerobic performance and change of direction, comparable to alternative approaches. However, the effects on repeated sprint ability and sprint performance are not consistently demonstrated.

Warm-Up Strategies and Effects on Performance in Racing Horses and Sport Horses Competing in Olympic Disciplines.

Warm-up is a standard component of exercise preparation, intended to lower the risk of injury and improve performance. Comprehensive evidence-based guidelines per discipline are missing. This scoping review aimed to describe the physiological effects and strategies of active warm-up in horses according to different equestrian disciplines. The search strategies identified 479 papers for review. After application of selection criteria, 23 articles published from 1996 to January 2024 were included of which 12 discussed the effects of warm-up on physiological parameters and 11 discussed warm-up strategies in different disciplines. As shown in humans, warm-up enhanced aerobic capacity and increased blood and muscle temperatures, independently from its intensity. Riders emphasized the importance of warm-up to prepare horses for physical work and to increase their reactiveness to aids. A canter or trot was the preferred gait in elite or non-elite dressage horses, respectively, while the walk was in show jumping horses. Warm-up duration and intensity increased with increasing competitive level, but a longer and/or more intensive warm-up did not affect the final score. Dressage riders warmed up their horses for a longer time compared to show jumping riders. Future studies should objectively establish the most profitable warm-up strategies per equestrian discipline and level.

Effect of foam rolling recovery on pain and physical capacity after resistance exercises: A randomized crossover trial.

OBJECTIVES: To compare the effects of passive recovery (PR), active recovery (AR), and recovery through self-massage with the aid of foam rolling (FRR) on pain and physical capacity in healthy volunteers after a resistance exercise (RE) session. METHODS: The sample of this randomized crossover trial comprised 37 physically healthy men who underwent three sessions of RE (squat, leg press, and leg extension), involving four sets of 10 repetitions with 80% of 10MR, with an interval of seven days between sessions. PR consisted of sitting for 20min, AR included a cycle ergometer for 20min at 50% maximum heart rate, and FRR involved 10 repetitions per target body area, followed by 1min rest. Variables of physical capacity (strength, power, agility, joint range of motion, flexibility, speed, and fatigue resistance) were assessed 1h after RE, whereas pain was assessed 24h, 48h, and 72h after RE. RESULTS: In the dominant lower limb, the percentage of strength decreased (p < 0.001) by 16.3% after RE but improved (p < 0.001) by 5.2% after AR and FRR in relation to PR. Similar results were observed in the non-dominant lower limb. Agility was enhanced (p < 0.001) by 3.6% in AR and 4.3% in FRR compared with the baseline assessment. The recoveries for the other physical variables were similar. Only FRR reduced (p < 0.001) pain at 24h (22.8%), 48h (39.2%), and 72h (59.7%) compared to PR. CONCLUSIONS: Self-massage using a foam roll reduced pain and improved agility and muscle strength during recovery after exercise. TRIAL REGISTRATION NUMBER: NCT04201977.

Effect of ß-alanine on the athletic performance and blood amino acid metabolism of speed-racing Yili horses.

The objective of this study was to examine the effects of supplemental ß-alanine feeding on the athletic performance of Yili horses involved in speed racing, focusing on alterations in plasma free amino acid patterns pre and post exercise. Additionally, the research aimed to evaluate the effects of carnosine on the plasma acid-base buffering capacity and antioxidant levels in these horses. Twelve Yili horse stallions, averaging 3 years in age and 346.50 ± 21.39 kg in weight, were chosen and randomly divided into two groups: a control group and a test group, each comprising six horses. The control group received a supplementation of 300 mg/kg BW/day of α-alanine, while the test group received 300 mg/kg BW/day of ß-alanine. This supplementation regimen was maintained for a 30-day supplementation trial period, under identical feeding and management conditions. Throughout the trial, the horses participated in the 1,000 Speed Race, and three distinct blood samples were gathered for assessing plasma free amino acids, blood gases, biochemical parameters, and antioxidant parameters. The outcomes indicated a considerable enhancement in the 1,000 m exercise performance of the speed racing Yili horses in the test group compared to the control group, showcasing a noteworthy improvement of 12.01%, with the test group completing the race 13.29 s faster. Notably, the α-alanine content in the plasma of the control group Yili horses remained higher than that of the test group, demonstrating a consistent increasing trend. By contrast, the plasma ß-alanine content was notably higher in the test group than in the control group. Over the course of the supplementation period, plasma ß-alanine exhibited an escalating and then stabilizing trend in the test group, whereas in the control group, although ß-alanine content also increased, the trend was less pronounced. The plasma levels of histidine and carnosine showed minimal variance between the two groups. Overall, the test group of Yili horses exhibited slightly higher plasma levels of histidine and carnosine compared to the control group. The addition of ß-alanine to their diet for a duration of 30 days notably affected the plasma levels of amino acids both pre- and post-exercise in speed-racing Yili horses. Furthermore, ß-alanine demonstrated an inhibitory effect on the catabolism of these horses' bodies during high-intensity exercise. Ten marker amino acids, including valine, leucine, ß-alanine, isoleucine, carnosine, 3-methyl-histidine, lysine, ethanolamine, argnine, and taurine, displayed statistically significant changes. ß-alanine notably increased the blood glucose levels of Yili horses and played a role in expediting the restoration of blood gas levels post-exercise. Moreover, in the test group of Yili horses, the levels of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity significantly increased both before and after the race, while the content of malondialdehyde, an oxidation product, exhibited an extremely significant decrease immediately after the race. These outcomes suggest that the addition of ß-alanine significantly augmented antioxidant levels during high-intensity exercise in Yili horses. Consequently, it reduced post-exercise injuries and accelerated the recovery process after exercise.