Locomotor and Physiological Demands of Small-Sided Soccer Games in Wildcard and Regular Players: Effects of Goalkeepers and Type of Wildcard.

BACKGROUND: Small-sided games (SSGs) are frequent training drills in soccer. This study investigated whether type of game (ie, with/without goalkeepers) and wildcard ( without vs internal vs external wildcard) impact the physiological (heartrate [HR]) and locomotor (total distance [TD] covered) demands in regular and wildcard players and to evaluate between-player and within-player variability. HYPOTHESIS: Demands are influenced by wildcard and game type, with higher demand (distance covered at high intensities and sprint speed) in regular players and with higher variability in SSG with wildcard players. STUDY DESIGN: Descriptive/comparative study. LEVEL OF EVIDENCE: Level 4. METHODS: Twenty-four soccer players completed 6 SSG as 3 versus 3 without (NG) or with (GK) goalkeepers, and with internal (NG+IW and GK+IW) and external (NG+EW and GK+EW) wildcard. Average HR (HRavg), rate of perceived exertion, and locomotor demands (TD, medium [MID = 7.0-13.9 km h-1], high [HID = 14.0-20.9 km h-1] and sprint [SPD >21.0 km h-1] distance and peak speed [PS]) were registered. RESULTS: The inclusion of GK and internal wildcard led to decreased HRavg and TD in regular players. Wildcard players positioned internally exhibited higher TD, PS, and lower HRavg than externally positioned wildcards. Regular players demonstrated higher TD, PS, MID, HID, HRavg and time spent in Z3 (>90% HRmax) compared with wildcard players in SSG played with external wildcard. Regular and wildcard players displayed great between- and within-player variability in high-intensity metrics. CONCLUSION: Specific game type and wildcard inclusion impact the physiological and locomotor demands in SSG, with variations observed between regular and wildcard players. CLINICAL RELEVANCE: This study provides comprehensive information on the physiological and locomotor demands of SSG depending on the inclusion and position of goalkeepers and wildcards, which can be useful for strength and conditioning coaches when designing specific training tasks, individualizing training load and applying return-to-play programs.

Effects of Different Conditioning Activities on the Sprint Performance of Elite Sprinters: A Systematic Review With Meta-Analysis.

PURPOSE: Postactivation performance enhancement (PAPE), which refers to the phenomena associated with the attainment of enhanced performance in sport-specific tasks after a conditioning activity, is an important objective of warming-up practices in many sports. This is even more relevant for sprinters, as potential increases in sprinting speed will directly influence their competitive results. This systematic review with meta-analysis evaluated the effects of different PAPE protocols (ie, using plyometrics, strength-power exercises, and resisted/assisted sprints) on the sprinting performance (ie, sprint time or sprint speed) of competitive sprinters. METHODS: Initially, 1205 records published until last December 18 were identified, using the following databases: PubMed/MEDLINE, Scopus, and Clarivate Web of Science. After removing duplicates and screening titles and abstracts, 14 high-quality studies met the inclusion criteria for the meta-analysis. RESULTS: Overall, there were no significant changes in sprint performance after implementing various types of conditioning activities (standardized mean difference [SMD] = 0.16 [95% CI, -0.02 to 0.33]; Z = 1.78; P = .08; I2 = 0%). In addition, when comparing prechanges and postchanges between experimental, control, and other conditions, no significant differences were found in sprint speed or time across all studies (SMD = 0.09 [95% CI, -0.10 to 0.28]; Z = 0.92; P = .36; I = 0%). CONCLUSIONS: Results revealed that different types of conditioning activities may not be capable of acutely enhancing the sprint speed of competitive sprinters. This aligns with previous observations indicating that sprinting is a highly stable physical capacity, a phenomenon that is even more consistent among elite sprinters. Coaches and sport scientists should collaborate to develop more efficient PAPE protocols for these highly specialized athletes, with special attention to study design and individualization, while considering their effects on acceleration versus top speed.

Ultramarathon runners and support crew: The influence of pre-race sleep and training profiles on performance in a 217-km mountain race.

The present study evaluates the effects of pre-race sleep and training characteristics among ultra-athletes and support crew, and the influence of these factors on the athlete's performance in a 217-km ultramarathon. A total of 38 ultramarathon runners and 59 support crew members were assessed. The participants answered questionnaires about chronotype, sleep quality, sleepiness, basic demographics, and pre-race training. The clinical trial registration number is RBR-7j6d23v. The results showed that athletes and support crew had a morning-type chronotype and good sleep efficiency; most had poor-quality sleep. The athletes who finished the race had a higher sleep latency than non-finishers (p < 0.001). The quality of sleep may have impacted performance because the athletes with good sleep quality trained one day more per week than those without (p < 0.001), and training frequency was highly correlated with the race time (r = -0.59). These findings are novel, expand the data about sleep, training, and performance in an ultramarathon, and innovate by addressing the support crew.

Optimal Prescription for Superior Outcomes: A Comparative Analysis of Inter-Individual Variability in Adaptations to Small-Sided Games and Short Sprint Interval Training in Young Basketball Players.

This study compared the inter-individual variability in adaptive responses to six weeks of small-sided games (SSG) and short sprint interval training (sSIT) in young basketball players. Thirty well-trained young athletes (age: 16.4 ± 0.6 years; stature: 190 ± 8.4 cm; weight: 84.1 ± 8.2 kg) voluntarily participated and were randomly assigned to SSG (3 sets of 5 min 3v3 on full length (28 m) and half-width (7.5 m) court, with 2 minutes of passive recovery in-between), sSIT (3 sets of 12 × 5 s sprinting with 20 s recovery between efforts and 2 min of rest between sets), or CON (routine basketball-specific technical and tactical drills) groups, each of ten. Before and after the training period, participants underwent a series of laboratory- and field-based measurements to evaluate their maximum oxygen uptake (V̇O2max), first and second ventilatory threshold (VT1 and VT2), oxygen pulse, peak and average power output (PPO and APO), linear speed, change of direction (COD), countermovement jump (CMJ), and vertical jump (VJ). Both SSG and sSIT sufficiently stimulated adaptive mechanisms involved in enhancement of the mentioned variables (p < 0.05). However, sSIT resulted in lower residuals in percent changes in V̇O2max (p = 0.02), O2pulse (p = 0.005), VT1 (p = 0.001), PPO (p = 0.03), and linear speed (p = 0.01) across athletes compared to the SSG. Moreover, sSIT resulted in more responders than SSG in V̇O2max (p = 0.02, φ = 0.500), O2pulse (p = 0.003, φ = 0.655), VT1 (p = 0.003, φ = 0.655), VT2 (p = 0.05, φ = 0.436), and linear speed (p = 0.05, φ = 0.420). Our results indicate that sSIT creates a more consistent level of mechanical and physiological stimulus than SSG, potentially leading to more similar adaptations across team members.

Microdosing Plyometric Training Enhances Jumping Performance, Reactive Strength Index, and Acceleration among Youth Soccer Players: A Randomized Controlled Study Design.

Microdosing can facilitate better accommodation to the training stimulus while aligning with the scheduling needs of teams. In this study, the effectiveness of microdosing exposure was investigated by comparing the effects of microdosing plyometric jump training (microPJT) with those of regular plyometric jump training (regPJT) and a control group not exposed to plyometric training. The comparison focused on the effects on jumping performance, reactive strength index (RSI), and acceleration over a 10-meter distance. Fifty-two male youth soccer players (16.3 ± 0.6 years old) from under-17 teams participated in a randomized controlled study, with interventions lasting 8 weeks. Assessments were conducted twice, before and after the intervention, measuring squat jump (SJ), countermovement jump (CMJ), RSI during drop jumps, and acceleration in a 10-meter sprint test. The regPJT group completed 34 bilateral jumps and 48 unilateral jumps per week over two weekly sessions, totaling 82 jumps. Conversely, the microPJT group performed 17 bilateral jumps and 24 unilateral jumps weekly over 4 sessions week, totaling 41 jumps. Significant interactions between groups and time were observed concerning SJ (p < 0.001; η2= 0.282), CMJ (p < 0.001; η2= 0.368), RSI (p < 0.001; η2= 0.400) and 10-m sprint time (p < 0.001; η2 = 0.317). Between-group analysis indicated that both the microPJT (p < 0.001) and regPJT (p < 0.001) groups exhibited significant better results compared to the control group in post-intervention evaluation of SJ, CMJ, RSI and 10-m sprint time, while no significant differences were found between experimental groups (p > 0.050). In conclusion, this study has revealed that both microPJT and regPJT are equally effective in enhancing jumping performance and acceleration time in soccer players. This suggests that a smaller training volume, distributed more frequently across the week, can effectively induce improvements in soccer players.

Effects of Sprint Interval Training Surface on Physical Fitness Attributes of Collegiate Female Soccer Players: Identifying Individual Responses to Training on Grass, Sand, and Land Surfaces.

This study aimed to identify the optimal surface for sprint interval training to maximize transfer effects on physical performance measures on the grass pitch. Using a randomized controlled trial design, 40 collegiate female soccer players were equally assigned to three experimental groups performing short sprint interval training (SSIT: 4 sets of 10 repetitions with 5 seconds all-out running, with a 50-second recovery period between each effort and a 3-minute rest interval between sets) on SAND, GRASS, LAND, and a control group. Before and after a 7-week training period, participants underwent a series of field-based tests to evaluate countermovement jump (CMJ), 20-m linear sprint, Illinois change of direction (CoD) speed, Yo-Yo IR1, 2.4 km time trial, and maximal kicking distance (MKD) performance. A two-way analysis of variance with repeated measures was conducted on the data, along with Bonferroni post hoc testing. After the intervention, the control group did not show any changes, while the SAND, GRASS and LAND training groups demonstrated improvements (p = 0.001) in their performance as follows: CMJ (effect size [ES] = 1.21, 0.97, 0.64), 20-m linear sprint (ES = -0.81, -0.55, -0.41), Illinois CoD (ES = -0.72, -0.79, -0.41), Yo-Yo IR1 (ES = 1.86, 1.19, 1.12), 2.4 km time trail (ES = -0.82, -0.62, -0.49), and MKD (ES = 0.60, 0.90, 0.72), respectively. Comparative analysis of SAND, GRASS, and LAND revealed that performing SSIT on SAND results in a significantly greater gain in CMJ than LAND (p = 0.041). Analyzing individual responses to training interventions indicated that the training surface had a favorable influence on CMJ (SAND vs. LAND, p = 0.009), but on other variables no statistically significant (p > 0.05) differences were observed. Considering these findings, it is advised that strength and conditioning coaches use the SAND surface as the initial choice for SSIT sessions regarding greater gains (i.e., ES) in performance. This recommendation aims to facilitate more favorable transfer in physical fitness adaptation on a soccer grass pitch. In case of unavailability of SAND surface, GRASS surface would be a suitable alternative to enhance the physical fitness of collegiate female soccer players.

Can The Pitch Dimension Influence the Physical Fitness Adaptations Induced by Small-Sided Training Programs Added to Regular In-Field Training? A Randomized Controlled Study in Youth Soccer Players.

Small-sided games (SSGs) are frequently utilized in training settings to elicit specific stimuli that can promote physical fitness adaptations over time. However, various task constraints, such as pitch dimensions, can significantly influence both the acute external and internal load responses. Thus, understanding the impact of different pitch dimensions on physical fitness adaptations is crucial. This study sought to compare the physical adaptations induced by an SSG-based program utilizing more elongated pitches (SSGlw2; length-to-width ratio: 2.0) versus less elongated pitches (SSGwl1; length-to-width ratio: 1.0) on the Yo-Yo intermittent recovery test level 1 (YYIRT), and 30-meter sprint. This study employed a randomized controlled design. Forty-eight male soccer players (16.4 ± 0.6 years) participated. These players were randomly allocated to two experimental groups (N = 16, SSGlw1; N = 16, SSGlw2) and underwent two weekly additional training sessions over an 8-week period, while a group of 16 players continued with their regular in-field sessions as a control group. Evaluations were conducted before and after the intervention period. Significant interactions time u group were observed in regards YYIRT (F = 15.857; p < 0.001; = 0.413) and 30-m sprint test (p < 0.001). Between-group differences on YYIRT were found in post-intervention (p < 0.001), on which SSGlw2 (p < 0.001) and SSGlw1 (p < 0.001) were significantly greater in comparison to control group. Additionally, between-group differences on 30-m sprint were found in post-intervention (p < 0.001), on which SSGlw2 was significantly better than SSGlw1 (p < 0.001) and control group (p < 0.001). Coaches are advised to prioritize the use of more elongated pitch sizes to promote adaptations in sprint performance, while still acknowledging that aerobic capacity improvements remain significant compared to other pitch shapes.

Nutritional Ergogenic Aids in Cycling: A Systematic Review.

This systematic review aimed to evaluate the effectiveness of the independent or combined use of nutritional ergogenic aids belonging to Group A of the ABCD classification by the Australian Institute of Sport (AIS) in the context of cycling (caffeine, creatine, sodium bicarbonate, beta-alanine, nitrates, and glycerol). A comprehensive search was carried out using three databases: PubMed, Scopus, and Web of Science. All the databases were searched for Randomized Controlled Trials or crossover design studies assessing the effects of supplementation on cycling performance in comparison with placebos in healthy adults. The methodological quality of each study was evaluated using the Physiotherapy Evidence Database scale. Thirty-six articles involving 701 participants were included in this review, examining supplementation with caffeine (n = 5), creatine (n = 2), sodium bicarbonate (n = 6), beta-alanine (n = 3), and nitrates (n = 8). Additionally, supplemental combinations of caffeine and creatine (n = 3), caffeine and sodium bicarbonate (n = 3), caffeine and nitrates (n = 1), creatine and sodium bicarbonate (n = 1), and sodium bicarbonate and beta-alanine (n = 4) were analyzed. A benefit for cyclists' athletic performnce was found when consuming a caffeine supplement, and a potential positive effect was noted after the consumption of sodium bicarbonate, as well as after the combination of caffeine and creatine. However, no statistically significant effects were identified for the remaining supplements, whether administered individually or in combination.

Reliability of Dynamic Shoulder Strength Test Battery Using Multi-Joint Isokinetic Device.

This study aimed to determine the absolute and relative reliability of concentric and eccentric flexion, extension, horizontal abduction, and adduction movements of the shoulder using a functional electromechanical dynamometer (FEMD). Forty-three active male university students (23.51 ± 4.72 years) were examined for concentric and eccentric strength of shoulder flexion, extension, horizontal abduction, and horizontal adduction with an isokinetic test at 0.80 m·s-1. Relative reliability was determined by intraclass correlation coefficients (ICCs) with 95% confidence intervals. Absolute reliability was quantified by the standard error of measurement (SEM) and coefficient of variation (CV). Reliability was very high to extremely high for all movements on concentric and eccentric strength measurements (ICC: 0.76-0.94, SEM: 0.63-6.57%, CV: 9.40-19.63%). The results of this study provide compelling evidence for the absolute and relative reliability of concentric and eccentric flexion, extension, horizontal abduction, and horizontal adduction shoulder isokinetic strength tests in asymptomatic adults. The mean concentric force was the most reliable strength value for all tests.

Mitigating against relative age effects in youth Track & Field: Validating corrective adjustment procedures across multiple events.

OBJECTIVES: With the aim to better identify talented Track & Field performance development, this study estimated the relationships between chronological (decimal) age with 60-m sprint, high jump, triple jump, and pole vault performance. Then, to mitigate against expected Relative Age Effects (RAEs), Corrective Adjustment Procedures (CAPs) were applied to an independent sample. DESIGN: Mixed-longitudinal design examining public data between 2005 and 2019. METHODS: The performances of 5339 Italian sprinters and jumpers (53.1 %) spanning 11.01-17.99 years of age were examined, with trendlines between chronological age and performance established. Related to an independent sample (N = 40,306; female 45.5 %), trendlines were then utilised to apply CAPs and adjust individual performance. Considering raw and adjusted performance data, RAE distributions were examined for the top 25 % and 10 % performers. RESULTS: For all male and female events, quadratic models best summarised the relationships between chronological age and performance (R2 = 0.74-0.89). When examining independent athletes in similar event, RAEs were more pronounced in males (Cramer's V = 0.35-0.14) than females (Cramer's V = 0.29-0.07). For both sexes, RAE magnitude decreased with age and increased according to performance level (i.e., Top25%-Top10%). However, following CAP applications, RAEs were reduced or removed within annual age groups and performance levels. CONCLUSIONS: With RAEs prevalent across Italian youth Track & Field events, findings validate CAPs as a strategy to account for the influence of relative age differences on athletic performance. CAPs help establish a more equitable strategy for performance evaluation and could help improve the efficacy of long-term athlete development programming.

Higher final speed in 30-15 intermittent fitness tests correlates with soccer's locomotor demands, not heart rate responses in small-sided soccer games.

This study aimed to achieve two objectives: firstly, to analyze the relationships between aerobic fitness, as represented by the VIFT, and the heart rate and locomotor responses of youth male soccer players across various teams; and secondly, to compare players with lower and higher VIFT in terms of performance outcomes extracted during small-sided games (SSGs). A total of twenty-six youth male soccer players, aged 16.5 ± 0.32 years, with 3.4 ± 1.1 years of experience, voluntarily participated in the study. These players belonged to two regional-level tier 2 teams (trained/developmental). In the initial week of observation, the 30-15 Intermittent Fitness Test was implemented to measure the final velocity (VIFT) achieved by the players. Subsequently, the 5v5 format of play was conducted twice a week over two consecutive weeks, during which heart rate responses and locomotor demands were measured. The Pearson product-moment correlation test revealed a significant correlation between VIFT and the total distance covered during the 5v5 format (r = 0.471 [95% CI: 0.093; 0.721], p = 0.015). Conversely, small and non-significant correlations were identified between VIFT and mean heart rate (r = 0.280 [95% CI: - 0.126; 0.598]; p = 0.166), VIFT and peak heart rate (r = 0.237 [95% CI: - 0.170; 0.569]; p = 0.243), as well as VIFT and high-speed running (r = 0.254 [95% CI: - 0.153; 0.580]; p = 0.211). Players with higher VIFT demonstrated a significantly greater total distance, with a large effect size (+ 6.64%; p = 0.015; d = 1.033), compared to those with lower VIFT. Our findings suggest that improved performance in VIFT may lead to covering more distance in 5v5 matches. However, the lack of significant associations between VIFT and heart rate levels during SSGs suggests that they are not strongly correlated, possibly because VIFT is more closely linked to locomotor profile. As a practical implication, coaches may consider organizing players during SSGs based on their VIFT if the goal is to standardize locomotor demands.

Effect of Heat Acclimatization, Heat Acclimation, and Intermittent Heat Training on Maximal Oxygen Uptake.

BACKGROUND: Maximal oxygen uptake (VO2max) is an important determinant of endurance performance. Heat acclimation/acclimatization (HA/HAz) elicits improvements in endurance performance. Upon heat exposure reduction, intermittent heat training (IHT) may alleviate HA/HAz adaptation decay; however, corresponding VO2max responses are unknown. HYPOTHESIS: VO2max is maintained after HAz/HA; IHT mitigates decrements in aerobic power after HAz/HA. STUDY DESIGN: Interventional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 27 male endurance runners (mean ± SD; age, 36 ± 12 years; body mass, 73.03 ± 8.97 kg; height, 178.81 ± 6.39 cm) completed VO2max testing at 5 timepoints; baseline, post-HAz, post-HA, and weeks 4 and 8 of IHT (IHT4, IHT8). After baseline testing, participants completed HAz, preceded by 5 days of HA involving exercise to induce hyperthermia for 60 minutes in the heat (ambient temperature, 39.13 ± 1.37°C; relative humidity, 51.08 ± 8.42%). Participants were assigned randomly to 1 of 3 IHT groups: once-weekly, twice-weekly, or no IHT. Differences in VO2max, velocity at VO2max (vVO2), and maximal heart rate (HRmax) at all 5 timepoints were analyzed using repeated-measure analyses of variance with Bonferroni corrections post hoc. RESULTS: No significant VO2max or vVO2 differences were observed between baseline, post-HAz, or post-HA (P = 0.36 and P = 0.09, respectively). No significant group or time effects were identified for VO2max or vVO2 at post-HA, IHT4, and IHT8 (P = 0.67 and P = 0.21, respectively). Significant HRmax differences were observed between baseline and post-HA tests (P < 0.01). No significant group or time HRmax differences shown for post-HA, IHT4, and IHT8 (P = 0.59). CONCLUSION: VO2max was not reduced among endurance runners after HA/HAz and IHT potentially due to participants' similar aerobic training status and high aerobic fitness levels. CLINICAL RELEVANCE: HAz/HA and IHT maintain aerobic power in endurance runners, with HAz/HA procuring reductions in HRmax.

Quantifying the Performance of Professional Athletes Following Traumatic Tibial Fractures.

INTRODUCTION: A tibial fracture is an uncommon, yet severe injury that occurs in professional athletes within all major sports leagues. These injuries are often debilitating for professional athletes and can require extensive rehabilitation prior to returning to play. The purpose of this study is to investigate the impact of a tibial fracture on athletic performance in all four major United States sports leagues. METHODS: A publicly available professional sports database, Pro Sports Transactions, was queried for tibial injuries from January 01, 2015, to May 31, 2023. The search included all four major U.S. sports leagues. To quantify and compare athletic ability before and after injury, performance-based statistics were collected from standardized player ratings in periods surrounding the date of injury. The percent change in player performance was measured and stratified. The Pearson correlation test was used to analyze player demographics. RESULTS: There were a total of 24 professional athletes who suffered 28 confirmed tibial fractures across all leagues. Upon return, there was a 14.7% decrease in overall player performance across all leagues. National Basketball Association, National Football League, and National Hockey League athletes had a decrease of 34.5%, 29.1%, and 14.2%, respectively, following their return to play. Major League Baseball players demonstrated an 8.1% increase in player performance following their recovery from tibial fracture. CONCLUSION: Players who suffer tibial fractures often undergo immediate surgery and, in unfortunate cases, may require multiple subsequent procedures. Additionally, athletes spend several months recovering prior to their return. Upon return, athletes' performance may be decreased; however, further study is required to strengthen the association between player performance and tibial fracture recovery.

Jump Squats Performed with Both Light and Heavy Loads Have Similar Effects on the Physical Performance of Elite Rugby Players during the Initial Phase of the Competitive Period.

We examined the effectiveness of two different jump-squat (JS) loading ranges on the physical performance of rugby players. Twenty-eight elite male rugby players were divided into two JS training groups: a light-load JS group ("LJS"; JS at 40% of the one-repetition maximum [1RM] in the half-squat (HS) exercise) and a heavy-load JS group ("HJS"; JS at 80% HS-1RM). Players completed the distinct training programs over four weeks, three times per week, during the initial phase of the competitive period. Pre- and post-training tests were conducted in the following sequence: vertical jumps, a 30-m speed test, peak power in the JS and the HS, and maximum isometric force in the HS. Additionally, the rating of perceived exertion (RPE) was assessed at the end of all training sessions throughout the intervention. A two-way ANOVA with repeated measures, followed by the Tukey's post-hoc test, was employed to analyze differences between groups. The level of significance was set at p < 0.05. Effect sizes were used to assess the magnitude of differences between pre- and post-training data. Except for the RPE values (which were lower in the LJS group), no significant changes were detected for any other variable. In summary, using either a light- (40% HS-1RM) or a heavy-load (80% HS-1RM) JS during the initial phase of the competitive period is equally effective in maintaining physical performance levels attained during the preceding training period (pre-season), with the significant advantage of the light-load protocol resulting in lower levels of the RPE. This finding may have important implications for resistance training programming, especially in disciplines where acute and chronic fatigue is always a problematic issue.

Do Activities Performed within the Intra-Contrast Rest Interval Affect Neuromuscular Performance during Complex-Contrast Training Protocols?

The aim of this study was to analyze the acute effects of including different exercises within the intra-contrast rest interval (ICRI) of a complex-contrast training (CCT) session. Seventeen recreationally active males completed three different CCT protocols. Programs consisted of a contrast pair combining a moderate-intensity conditioning activity (i.e., a back squat) with a lower-body high-velocity exercise (i.e., a vertical jump) and only differed in the activities performed during the ICRI: 1) passive recovery (CCTPASS); 2) a mobility exercise (CCTMOB); and 3) an upper-body high-intensity strength exercise (i.e., a bench press) (CCTSTR). Countermovement jump and bench press throw metrics were evaluated at baseline and after each set during the workout. The rate of perceived exertion was recorded post-session. Non-significant differences in performance were found between CCTPASS, CCTMOB and CCTSTR throughout the session. Significant declines (p < 0.05) were observed for CMJ peak power in the last 2-3 repetitions of each set, irrespective of the protocol. CCTSTR was perceived as more intense than CCTPASS and CCTMOB (p < 0.05). From a neuromuscular performance perspective, including activities during the ICRI (mobility drills or high-intensity strength exercises) may be a suitable strategy to optimize CCT prescription since the acute responses were similar to those found with passive rest periods. Finally, prescribing a lower number of repetitions per set is recommended to attenuate mechanical performance impairment during CCT protocols, irrespective of the activities completed within the ICRI.

Electromechanical efficiency index of skeletal muscle and its applicability: a systematic review.

Introduction: The electromechanical efficiency of skeletal muscle represents the dissociation between electrical and mechanical events within a muscle. It has been widely studied, with varying methods for its measurement and calculation. For this reason, the purpose of this literature review was to integrate the available research to date and provide more insights about this measure. Methods: A systematic search of the literature was performed across three online databases: PubMed, ScienceDirect, and SPORTDiscus. This yielded 1284 reports, of which 10 met the inclusion criteria. Included studies have used different methods to measure the electromechanical efficiency (EME) index, including electromyography (EMG), mechanomyography and tensiomyography (TMG). Results: The EME index was used to assess muscle conditions such as muscle atrophy, pain syndromes, or to monitor rehabilitation in patients with knee problems, fatigue and the effects of exercise and rehabilitation. TMG has been shown to be one of the most reliable methods to obtain the EME index, but its use precludes obtaining the index during voluntary muscle contractions. Conclusion: Standardizing the EME index is crucial for its diverse applications in clinical, sport, and rehabilitation contexts. Future research should prioritize standardization of measurement protocols for establishing the most repeatable, and reliable approach that can be used for inter-individual comparisons or for assessing an individual for multiple times over a longer period. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023440333 Identifier: CRD42023440333.

Effects of Myofascial Release Techniques on Joint Range of Motion of Athletes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Although myofascial release techniques (MRTs) are commonly used to improve athletes' range of motion (ROM), the effectiveness of MRTs may vary depending on the specific method performed. This systematic review and meta-analysis aimed to evaluate the effects of MRTs on the ROM performance of athletes. (2) Methods: The electronic databases of Cochrane Library, PubMed, Scopus, and Web of Science were searched to identify relevant articles published up to June 2023. This study utilized the PRISMA guidelines, and four databases were searched. The methodological quality of the studies was assessed using the PEDro scale, and the certainty of evidence was reported using the GRADE scale. The overall effect size was calculated using the robust variance estimator, and subgroup analyses were conducted using the Hotelling Zhang test. (3) Ten studies met the inclusion criteria. The overall effect size results indicated that the myofascial release intervention had a moderate effect on ROM performance in athletes when compared to the active or passive control groups. (4) Conclusions: Alternative MRTs, such as myofascial trigger point therapy, can further improve the ROM performance of athletes. Gender, duration of intervention, and joint type may have a moderating effect on the effectiveness of MRTs.

Effects of a Low Dose of Orally Administered Creatine Monohydrate on Post-Fatigue Muscle Power in Young Soccer Players.

The use of creatine monohydrate (Cr) in professional soccer is widely documented. However, the effect of low doses of Cr on the physical performance of young soccer players is unknown. This study determined the effect of a low dose of orally administered Cr on muscle power after acute intra-session fatigue in young soccer players. Twenty-eight young soccer players (mean age = 17.1 ± 0.9 years) were randomly assigned to either a Cr (n = 14, 0.3 g·kg-1·day-1 for 14 days) or placebo group (n = 14), using a two-group matched, double-blind, placebo-controlled design. Before and after supplementation, participants performed 21 repetitions of 30 m (fatigue induction), and then, to measure muscle power, they performed four repetitions in half back squat (HBS) at 65% of 1RM. Statistical analysis included a two-factor ANOVA (p ˂ 0.05). Bar velocity at HBS, time: p = 0.0006, ŋp2 = 0.22; group: p = 0.0431, ŋp2 = 0.12, time × group p = 0.0744, ŋp2 = 0.02. Power at HBS, time: p = 0.0006, ŋp2 = 0.12; group: p = 0.16, ŋp2 = 0.06, time × group: p = 0.17, ŋp2 = 0.009. At the end of the study, it was found that, after the induction of acute intra-session fatigue, a low dose of Cr administered orally increases muscle power in young soccer players.

Plyometric Jump Training Effects on Maximal Strength in Soccer Players: A Systematic Review with Meta-analysis of Randomized-Controlled Studies.

BACKGROUND: Maximal strength may contribute to soccer players' performance. Several resistance training modalities offer the potential to improve maximal strength. During recent years, a large number of plyometric jump training (PJT) studies showed evidence for maximal strength improvements in soccer players. However, a comprehensive summary of the available data is lacking. OBJECTIVE: To examine the effects of PJT compared with active, passive or intervention controls on the maximal strength of soccer players, irrespective of age, sex or competitive level. METHODS: To perform a systematic review with meta-analysis following PRISMA 2020. Three electronic databases (PubMed, Web of Science, and SCOPUS) were systematically searched. Studies published from inception until March 2023 were included. A PICOS approach was used to rate studies for eligibility. The PEDro scale was used to assess risk of bias. Meta-analyses were performed using the DerSimonian and Laird random-effects model if ≥ 3 studies were available. Moderator and sensitivity analyses were performed, and meta-regression was conducted when ≥ 10 studies were available for a given comparison. We rated the certainty of evidence using GRADE. RESULTS: The search identified 13,029 documents, and from these 30 studies were eligible for the systematic review, and 27 for the meta-analyses. Overall, 1,274 soccer players aged 10.7-25.0 years participated in the included studies. Only one study recruited females. The PJT interventions lasted between 5 and 40 weeks (median = 8 weeks), with 1-3 weekly sessions. Compared to controls, PJT improved maximal dynamic strength (18 studies, 632 participants [7 females], aged 12.7-24.5 y; effect size [ES] = 0.43, 95% confidence interval [CI] = 0.08-0.78, p = 0.017, impact of statistical heterogeneity [I2] = 77.9%), isometric strength (7 studies; 245 participants, males, aged 11.1-22.5 y; ES = 0.58, 95% CI = 0.28-0.87, p < 0.001, I2 = 17.7%), and isokinetic peak torque (5 studies; 183 participants, males, aged 12.6-25.0 y; ES = 0.51, 95% CI = 0.22-0.80, p = 0.001, I2 = 0.0%). The PJT-induced maximal dynamic strength changes were independent of participants' age (median = 18.0 y), weeks of intervention (median = 8 weeks), and total number of training sessions (median = 16 sessions). The certainty of evidence was considered low to very low for the main analyses. CONCLUSIONS: Interventions involving PJT are more effective to improve maximal strength in soccer players compared to control conditions involving traditional sport-specific training. Trial Registration The trial registration protocol was published on the Open Science Framework (OSF) platform in December 2022, with the following links to the project ( https://osf.io/rpxjk ) and to the registration ( https://osf.io/3ruyj ).