Optimizing Performance: Training Strategies to Improve Strength, Speed, and Power

Objectives: This study aimed to compare the acute responses of the muscular activity of primary movers during bench press execution under asymmetric loads (25%, 50%, and 75%). Methods: The study included 30 resistance-trained males (n = 25, age = 22.73 ± 3.44 years, height= 1.77 ± 0.06 m, body mass= 76.77 ± 9.28 kg) and females (n = 5, age = 22.5 ± 1.19 years, height = 1.63 ± 0.04 m, body mass = 56.78 ± 2.90 kg). We assessed the two portions of the dominant pectoralis major, triceps brachii, anterior deltoid, and both external oblique peak activities (sEMG) during concentric and eccentric phases. We performed a repeated-measures design to establish the differences between muscle activity, barbell center of mass acceleration, and OMNI-Perceived Exertion Scale for Resistance Exercise (OMNI-RES) in a bench press under seven different conditions. Results: The linear mixed model showed a significant fixed effect for exercise condition for muscles (p < 0.001) in the concentric and eccentric phases. We found significantly higher clavicularis (d = 0.54; d = 1.15) and sternalis (d = 0.38; d = 0.86) pectoralis major activation of the dominant side under high (50% and 75%), non-dominant-side, de-loaded conditions in the eccentric phase (p < 0.001), with large effects. Contralateral core muscles (external oblique) of the dominant and non-dominant sides were significantly (p < 0.001) highly activated under all asymmetric conditions in the concentric phase (from d = 0.89 to d = 2.30). Conclusions: The asymmetric load bench press provoked a higher pectoralis major activation on the loaded side when de-loading the other side. The contralateral external oblique doubles the muscle activity in the most asymmetric conditions. Full article

Background: We examined the effects of linear position transducer placement during Smith machine (SM) and free weight (FW) full squats on the mean velocity and the load–velocity relationship in trained women. In addition, we examined the relationship between the load–velocity characteristics and jump performance, to determine which testing approach is more appropriate for both the testing and transfer of training effects. Methods: Eleven trained women were assessed for 1-RM in FW and SM full back squats. Linear position transducers (LPTs) were attached to the barbell (BAR) and to the belt (BELT) during FW and SM full back squats. The mean velocity was measured across progressively increasing loads (30–100%). The load–velocity relationships were modeled using linear regression, and the velocity values, as well as the load–velocity parameters, were compared across all conditions (SM BAR, SM BELT, FW BAR, and FW BELT). Squat jump, countermovement jump, and drop jump performance were also assessed using an optical measurement system. Results: In SM compared to FW, 1-RM was higher (92.9 ± 16.2 kg vs. 85.1 ± 14.5 kg, p < 0.05, d = 0.53). A strong agreement was observed between the FW BAR and FW BELT (Lin’s concordance correlation coefficient CCC = 0.96–0.99), as well as between the SM BAR and FW BAR (CCC = 0.95–0.97) at low-to-moderate intensities (30–70% 1-RM), suggesting that these conditions can be used interchangeably. However, the SM BELT systematically showed lower mean velocity values at 30–80% 1-RM and exhibited low agreement across all other conditions. In contrast, the FW BELT mean velocity was lower than that of the FW BAR and SM BAR only at higher intensities (>80% 1-RM). V0 and mean velocities at low-to-moderate loads (30–70% 1-RM) showed strong correlations with all jump types, with relationships gradually weakening as the load increased (r = 0.63–0.93, p < 0.05). The highest correlations were observed in the SM BAR and FW BELT conditions. Lastly, the relative strength demonstrated a consistent relationship with squat jump and drop jump performance exclusively in the FW condition (r = 0.71 and 0.72, p < 0.05). Conclusions: The FW BAR and FW BELT showed strong agreement at submaximal loads and may be used interchangeably, while the SM BELT showed a lower mean velocity and low agreement with other conditions. The load–velocity relationship parameters and mean velocity at low-to-moderate loads correlated strongly with the jump performance. Coaches and practitioners can use bar-mounted and belt-mounted LPTs interchangeably during FW squats for velocity-based training at submaximal intensities when working with trained women. Additionally, tracking the mean velocity at low-to-moderate loads provides valuable insights into lower-body explosive performance, supporting more precise and individualized training prescriptions and performance monitoring. Full article

Objectives: This study aimed to compare the worst-case scenario (WCS; i.e., 1-min) demands, in terms of distance covered and the number of times exceeding 85% of WCS demands, across soccer playing positions and match periods. Methods: A total of 67,518 records from 380 soccer matches during the 2023/24 season of the First Spanish Division were collected. Match events were tracked using the optical tracking system ChyronHego^® (TRACAB Gen5, NY, USA) and synchronized with Mediacoach software (LaLiga, Madrid, Spain). Total distance (TD), very high-speed running (VHSR), and sprint distance were considered, and all analyses were performed using linear mixed models (LMM). Results: Center-backs (CBs) exhibited significant differences (p < 0.001) in TD compared to all other positions. Regarding actions exceeding 85% of the 1-min WCS for TD, full-backs (FBs) showed significant differences compared to CBs (p < 0.001), midfielders (MDs; p < 0.001), and attacking midfielders (AMs; p < 0.001). In terms of VHSR, significant differences were observed between MDs and wingers (Ws; p < 0.05). In relation to match periods, during 15–30, CBs demonstrated significant differences compared to all other positions for actions exceeding 85% of the 1-min WCS in TD. Conclusions: These findings suggest that training protocols could be adjusted to account for specific positional demands, particularly focusing on high-speed running and sprint actions. Full article

Background: Basketball necessitates high-intensity, intermittent efforts with multidirectional and unpredictable movements, requiring training strategies that enhance players’ physical capacity to meet these demands efficiently. This study aimed to examine the effects of a velocity-based curve differential sprinting training on the overall performance of young male basketball players. Methods: A total of 24 participants were tested for single- and double-legged counter-movement jump (CMJ) height, 10 m linear sprint time, and agility performance in a pre–post–retention test design. The 12-week intervention consisted of two weekly sessions with differential sprint training in addition to normal basketball training. Sessions consisted of two sets of ten 20 m sprints whereby participants were instructed to perform additional fluctuations in joints velocity for each repetition. Results: Results show strong evidence for H₁ (significant effect) for the experimental group in CMJ height (right leg) (BF₁₀ = 19.24) between pre-, post-, and retention test values (BF₁₀ = 10.24–17.85). For the remaining variables, no significant differences were observed. In contrast, the control group showed no significant effects including sprinting variables, indicating limited training effects. Conclusions: In conclusion, this research found that the 12-week differential curve sprinting training improved physical performance in the CMJ for the experimental group. Therefore, adding velocity-based random fluctuations during curve sprint training could be an effective training strategy for enhancing jumping performance in youth basketball players, which should encourage practitioners to implement different variations of the differential training approach. Full article

Background/Objectives: Futsal players need peak strength, functional capacity, speed, and explosive lower-limb power for optimal performance. The aim of this study was to (i) characterize and compare anthropometric characteristics, lower limb strength/power, dynamic balance, linear sprint speed, COD performance, and COD deficit across young futsal age groups and (ii) identify key predictors of COD deficit. Methods: Thirty-three male futsal players from three age groups (U13, U15, and U17) were tested. Results: All anthropometric variables showed significant group effects with moderate to strong effect sizes, where U17 presented the largest values, followed by U15 and U13. Strength and power variables presented the same trend. The dynamic balance differed significantly across groups. Significant differences between groups with moderate effect sizes were noted in linear sprints (F = 19.54, p < 0.001, η² = 0.57), zigzag (F = 19.54, p = 0.002, η² = 0.35), and COD deficit (F = 19.54, p < 0.001, η² = 0.46). Post hoc tests revealed that U13 and U15 outperformed U17 in the COD deficit (p < 0.002). The COD deficit showed a quadratic relationship with age, initially improving but later declining in older players (p < 0.001). The body mass and the posteromedial relative difference predicted the COD deficit, with the coefficient of determination (R²) explaining 39% of the COD variance. Conclusions: Coaches and practitioners should utilize COD drills to target various movement patterns and account for pubertal timing, as growth can impact performance. Full article

Background/objectives: This study aimed to compare the effects of bilateral and unilateral flywheel training programs on leg strength, sprint performance, jumping, and change of direction ability in young basketball players. Methods: Twenty-two youth male basketball players were randomly assigned to two groups: the unilateral group (UG; n = 11; age = 15.5 ± 0.5 years) and the bilateral group (BG; n = 11; age = 15.2 ± 0.4 years). Both groups participated in a six-week flywheel training intervention (UG: split squat; BG: half squat) alongside their regular basketball activities. Performance measures included change of direction ability (5-0-5 test), knee extension 60 degrees/s leg strength (EX60), bilateral and unilateral countermovement jump heights (CMJ, CMJL, and CMJD), reactive strength index (RSI), and 5 m and 20 m sprint times (SPR5m and SPR20m). A 2 × 2 ANOVA was used to evaluate pre- to post-intervention changes. Results: Significant interaction effects were observed for the 5-0-5 test (F = 13.27; p = 0.02), with pre–post improvements of 8.4% and 13.3% for the BG and UG, respectively. Both groups showed significant CMJ improvements (11.4%, ES = 0.69 for the BG; 14.6%, ES = 1.4 for the UG). The UG demonstrated greater unilateral jump improvements compared to the BG. Significant RSI improvements were found for both groups (BG: 19.6%, ES = 0.95; UG: 19.6%, ES = 0.77). Both groups improved on sprint performance, with the UG showing slightly larger effect sizes. Conclusions: Unilateral flywheel strength training appeared to be a more effective strategy than bilateral training for enhancing strength, sprinting, jumping, and change of direction ability in youth basketball players. Full article

Background: Squat exercises are widely recognized for their ability to improve sports performance. Recent advancements in force/velocity profiling have highlighted the importance of power and velocity in explosive movements. While various training methods have been applied to enhance these parameters, their effectiveness remains inconsistent. Focal vibration has emerged as a potential intervention, yet its impact on squat performance has not been extensively explored. The aim was to evaluate the effectiveness of focal vibration with voluntary contractions on power/velocity during a squat exercise in amateur athletes in comparison with voluntary contraction in isolation. Methods: A double-blind, randomized clinical trial with 72 amateur athletes. Velocity, power, muscle activity, perceived effort, and clinical change were measured. The experimental group received focal muscle vibration therapy (100–180 Hz) combined with voluntary contraction, while the sham group underwent identical procedures and focal muscle vibration without the vibrating head, close to the muscle belly but without touching the skin. Results: Statistically significant improvements in the experimental group were found for mean power (p < 0.001; ES = 0.08), peak velocity (p < 0.010; ES = 0.42), and mean velocity (p < 0.001; ES = 0.66) during the squat. Between-group analysis favored the experimental group in peak power (p < 0.049; ES = 0.65), mean power (p < 0.034; ES = 1.42), peak velocity (p < 0.024; ES = 0.095), and mean velocity (p < 0.002; ES = 1.67). Conclusions: Focal muscle vibration (100–180 Hz) combined with active muscle contraction significantly enhances power and velocity during squat exercises in amateur athletes. Full article

Objectives: The relationship between the isokinetic maximal strength of internal or external shoulder rotation and serve speed in tennis is well established, yet the influence of segmental mass, height, and high-speed shoulder rotation strength on serve performance in junior players remains unclear. This study aimed to investigate the relationship between concentric or eccentric isokinetic shoulder strength, segmental mass, height, and first-serve speed aimed at the T-target zone. Methods: Fifteen male junior competitive tennis players (mean ± SD: age 15.9 ± 0.9 years; height: 180.1 ± 7.2 cm; body mass: 66.1 ± 5.7 kg) were assessed for maximal isokinetic strength during concentric and eccentric internal and external shoulder rotations. Segmental mass (arm, leg, and trunk) was measured using dual-energy X-ray absorptiometry, and serve speed was recorded using a radar gun. Results: Concentric shoulder rotations at 210°/s demonstrated significant positive correlations with serve speed for both external (ρ = 0.71, p ≤ 0.01) and internal rotation (ρ = 0.61, p ≤ 0.05). Although lean arm mass partially mediated the relationship between shoulder strength and serve speed (indirect effect = 0.502, 95% CI: −0.156 to 1.145), this mediation effect was not statistically significant. Height was moderately correlated with serve speed (ρ = 0.68, p ≤ 0.01) but did not moderate the relationship between shoulder strength and serve speed. Conclusions: Concentric shoulder strength at higher angular velocities and segmental mass contribute to serve speed in junior tennis players. While height provides structural advantages, strength and lean mass play important roles, emphasizing the need for targeted training programs. Full article

Background/Objectives: The aim of the present study was to investigate the effect of two long-term reduced concurrent training frequencies (incorporating power training for the upper and high-intensity interval aerobic training for the lower extremities), in which participants performed one training session every either 7 or 14 days, after 12 weeks of systematic concurrent training on upper extremities’ muscle strength, power, and morphology in young females. Methods: After a 12-week concurrent resistance and aerobic training period, participants were assigned into three groups and performed either one training session every 7 days (G7), or once every 14 days (G14), or detraining (GD) for 12 weeks, followed by 12 additional weeks of detraining. Results: Performance and muscle mass increased after the initial 12-week training period. After the reduced training frequency period, bench press 1-RM and aerobic power remained unchanged in G7 and decreased significantly in G14 (−5.9 ± 4.9%; −1.4 ± 4.5%). Muscle power and muscle thickness of the triceps branchii long head decreased significantly in G7 (−9.8 ± 7.7%; −0.9 ± 0.6%; respectively, p < 0.05) and G14 (−10.9 ± 7.6%; −2.8 ± 2.7%, respectively, p < 0.05), without significant differences between groups (p > 0.05). Conclusions: In conclusion, 12 weeks of systematic concurrent resistance (upper extremities) and aerobic training (lower extremities) induced significant improvements in upper extremities muscle power/strength and muscle architecture characteristics. Both reduced training frequencies led to significant reductions in power performance. Thus, performing one training session every 2 weeks for 3 months may preserve 90 to 95% of the muscle power/strength, aerobic power and 72% of muscle mass adaptations achieved with systematic concurrent training. However, greater preservations in the above parameters could be observed if the training frequency is one training session per week. Full article

Background: The tempo of resistance exercises is known to influence performance outcomes, yet its specific effects on post-activation performance enhancement (PAPE) remain unclear. This study aimed to investigate the effects of fast versus slow repetitions at a load of 70% of one-repetition maximum (1-RM) in the bench press exercise, focusing on velocity, surface electromyographic (sEMG) activity, and applied force while equating time under tension on bench press throw performance. Methods: Eleven men (age: 23.5 ± 5.4 years, height: 1.79 ± 0.04 m, body mass: 79.1 ± 6.4 kg, maximum strength 1-RM: 91.0 ± 12.0 kg) participated. Two experimental conditions (FAST and SLOW) and one control (CTRL) were randomly assigned. Participants performed two sets of six repetitions as fast as possible (FAST condition) and two sets of three repetitions at a controlled tempo (SLOW condition) at half the concentric velocity of FAST, as determined in a preliminary session. Before and after the bench press participants performed bench press throws tests (Pre, 45 s, 4, 8, and 12 min after). Results: sEMG activity and peak force during the bench press were higher in FAST vs. SLOW conditioning activity (p < 0.001), with time under tension showing no significant differences between conditions (p > 0.05). Mean propulsive velocity (MPV) during the bench press throw improved equally in both FAST and SLOW conditions compared with baseline from the 4th to the 12th min of recovery (FAST: +6.8 ± 2.9% to +7.2 ± 3.3%, p < 0.01, SLOW: +4.0 ± 3.0% to +3.6 ± 4.5%, p < 0.01, respectively). Compared to the CTRL, both conditions exhibited improved MPV values from the 4th to 12th min (p < 0.01). Peak velocity improvements were observed only after the FAST condition compared to the baseline (p < 0.01) with no differences from SLOW. For all muscles involved and time points, sEMG activity during bench press throws was higher than CTRL in both experimental conditions (p < 0.01), with no differences between FAST and SLOW. Peak force increased in both FAST and SLOW conditions at all time points (p < 0.05), compared to CTRL. Conclusions: These findings suggest that post-activation performance enhancement is independent of movement tempo, provided that the resistive load and total time under tension of the conditioning activity are similar. This study provides valuable insights into the complex training method for athletes by demonstrating that varying tempo does not significantly affect post-activation performance enhancement when load and TUT are equated. Full article

Background/Objectives: Team handball involves a high number of rapid and forceful muscle actions. Progressive heavy-load resistance training is known to enhance mechanical muscle function; however, its transfer into functional performance in team handball athletes remains largely unknown. The current study aimed to analyze the effects of eight weeks undulating heavy-load resistance training on lower limb mechanical muscle function and sports-specific performance in elite female team handball players. Methods: Players from the Danish Women’s Handball League were block randomized to perform an off-season resistance training program (RT, n = 12, 23.0 ± 2.7 yr) or follow a training-as-usual control program (CON, n = 15, 24.1 ± 3.8 yr). All study participants were tested before and after an eight-week period during the off-season phase, including assessments of maximal isometric knee extensor and flexor peak torque, rate of torque development, countermovement jump (CMJ) power/work, and sports-specific performance (maximal vertical countermovement jump height, sprint capacity, team handball-specific on-court agility). Results: Agility performance improved for RT (−3.5%, p = 0.008), different from CON (p < 0.001) following eight weeks of designated resistance training. Additionally, CON demonstrated impaired agility (+4.0–7.3%, p < 0.05) and 20-m sprint (+1.9%, p = 0.002) performance. Maximal knee extensor peak torque increased in RT (4.5%, p = 0.044). Vertical CMJ flight height (JH) increased in both groups (RT +4.8%, p = 0.012, CON +8.4% p = 0.044); however, jump height relative to ground level (JHGL) increased in RT only (+8.0%, p = 0.013). Conclusions: In conclusion, designated resistance training during the off-season period is effective in maintaining and improving essential components of sports-specific performance and maximal knee extensor strength in elite female team handball players. Comparable protocols of twice-a-week heavy-load resistance training may also be beneficial in other types of intermittent elite team sports (i.e., football, basketball) that include maximal jumping actions, short-distance sprints, and rapid change of direction movements. Full article

Background: Evaluations of the usability of hydraulic resistance for resisted sprint-training purposes remains rare. Thus, this study compared step-by-step changes in spatiotemporal characteristics during the first 10 m of sprints with varying hydraulic resistance loads. Methods: Fourteen male athletes performed 20 m sprints under minimal (10 N, considered as normal sprint), moderate (100 N), and heavy (150 N) hydraulic resistance loads. Split times at 10 m, contact time (CT), step length (SL), flight time, and step speed (SS) from the first to the sixth step were measured. A two-way repeated measures ANOVA (load × step) and a one-way ANOVA (load) with post hoc comparisons were used to assess the effects on spatiotemporal characteristics and split times, respectively. Results: Under higher loads, the 10 m times were significantly longer (η² = 0.79). The CT, SL, and SS varied significantly from step to step within all loads (η² = 0.45, 0.41, and 0.54, respectively). The CT, SL, and SS of the first, fourth, fifth, and sixth steps of normal sprint differed significantly from most steps under moderate and heavy load (Cohen’s d = −3.09 to 5.39). In contrast, the smallest differences were observed between the second and third step of normal sprint and second to sixth steps under heavy load (Cohen’s d = −0.67 to 1.32, and −0.71 to 1.38, respectively). Conclusions: At the same load settings, a hydraulic resistance device induces changes in step characteristics comparable with those of other motorized devices and is therefore a viable option for resisted sprint training. If the goal of the training is to replicate the steps of the initial sprint acceleration phase, ~150 N of hydraulic resistance would be optimal. Full article

Background and Objectives: This study investigates the effects of a five-week training program on the medial gastrocnemius muscle, comparing two approaches: blood flow restriction (BFR) training and normobaric hyperoxia (oxygen supplementation). It evaluates three strengthening modalities (dynamic, isometric, and the 3/7 method) analyzing their impact on maximal voluntary contraction (MVC), muscle architecture, and perceived exertion. Methods: A total of 36 young healthy participants (21 females, 15 males) were randomized into six subgroups (n = 6 each) based on the type of contraction and oxygen condition. Training sessions (three per week) were conducted for five weeks at 30% of MVC. Measurements of MVC, muscle circumference, pennation angle, fascicle length, and perceived exertion were taken at baseline (T0), mid-protocol (T1), and post-protocol (T2). Results: All groups demonstrated significant increases in MVC after five weeks, with no notable differences between BFR and oxygen conditions. Structural changes were observed in specific subgroups: the BFR-isometric group showed increased calf circumference (p < 0.05), and the 3/7 groups exhibited significant fascicle length gains (p < 0.05). Perceived exertion was consistently higher in BFR groups compared to oxygen supplementation, particularly in dynamic exercises. Conclusions: Both BFR and oxygen supplementation are effective in enhancing strength with light loads, though they elicit different structural and perceptual responses. Oxygen supplementation may be more comfortable and less strenuous, offering a viable alternative for populations unable to tolerate BFR. Future research should focus on optimizing training parameters and exploring applications tailored to specific athletic or clinical contexts. Full article

Background: This study compared the effects of low- and moderate-volume supplementary plyometric training in preadolescent female handball players. Methods: Thirty-nine preadolescent handball players (age: 12.9 ± 0.5 years, maturity offset: −1.50 ± 0.56 years) were randomly assigned into three groups: low-volume plyometric training group (LPT, n = 12); moderate-volume plyometric training group (MPT, n = 15); and control group (CG, n = 12). The supplementary plyometric training program was performed twice per week for 10 weeks, along with normal training (3 times/week). Each supplementary session included two upper- and three lower-body exercises performed for two sets (LPT, 36–54 foot contacts, duration 12 min) or four sets (MPT, 72–108 foot contacts, duration 24 min). The CG performed technical handball drills for 20 min. Results: Compared with the control group, both LPT and MPT resulted in similar improvements in modified T-test performance (15.1% and 18.6%, p < 0.01, respectively); linear sprint performance over 5, 10, and 20 m (between 5.1% and 8.8%, p = 0.02 to 0.001); countermovement jump (28.0% and 22.1%, p < 0.05, respectively); and standing long jump (12.6% and 12.5%, p = 0.024, respectively). Handgrip strength and overarm shot ball velocity improved similarly in all groups (CG, MPT, and LPT), by 8–11% (p < 0.01). Conclusions: Very-low-volume supplementary plyometric training performed for 12 min per session for two sessions per week results in considerable improvements in running speed, change of direction ability, and leg power and is as effective as a moderate-volume program. These findings are important for pre-adolescent female team sports players, who may benefit from a minimal but effective supplementary training, resulting in large benefits in leg speed and power. Full article

To investigate how contextual or environmental factors may influence the athletic performance of female soccer players during competitions, this study aimed to assess the impact of match-related variables (playing surface; opponent levels; opponent result trends; match status, and match outcomes) on the athletic performance of professional female soccer athletes. Seventeen athletes (25.5 ± 4.3 years of age) from the same team competing in the Italian second division were divided into two groups according to their roles and athletic characteristics: Group A (central defenders and forwards) and Group B (right/left full-backs and midfielders). Total distance (TD) and sprint distance (SD); high-speed running (HSR), acceleration (ACC), and deceleration numbers (DEC); average and maximal heart rate (HR_avg; HR_max); and match-related factors were collected during the 22 regular season matches. A T-test and ANOVA were used to calculate the differences between groups in GPS and HR variables and the effects of match-related factors, respectively. Results showed higher running performance in the B group compared to the A group during matches. Increased ACC number was seen in matches played on artificial turf; winning was associated with decreased HR_max and increased DEC number. Athletes covered higher TD reaching lower HR_max when playing against lower-ranking opponents while matches lost/drawn resulted in higher HSR. High HRs (max and avg) were found when playing against a team with a positive performance trend. In summary, match-related factors and opponents’ characteristics can affect athletic performance in female soccer athletes. These factors should be considered during in-seasonal training to personalize match preparation and optimize athlete performance. Full article

Background: Maturation is a complex biological process affecting all tissues, organs, and systems, particularly during adolescence. The Peak Height Velocity (PHV) period, a hallmark of adolescent growth spurts, is associated with individual differentiations in the development of performance attributes amongst youth. Understanding the influence of sports participation on strength and power during the PHV period is essential for optimizing training outcomes and reducing injury risk. This scoping review synthesizes the literature on the strength and power development in athletes during the PHV period across various sports, highlighting the interaction between maturation, training, and performance outcomes. Methods: A systematic search of PubMed and Scopus, supplemented by manual searches, identified peer-reviewed studies from 2004 to 2025. The included longitudinal studies involved structured training and assessed strength-related performance during and around the PHV period. PRISMA-ScR guidelines were followed. Results: Twelve studies met the inclusion criteria. It is found that strength and power are significantly affected during the PHV period and participation in sports mitigates these effects. Training characteristics such as training frequency/volume and sport specificity were key factors. Early maturers often outperformed late maturers, though adolescent awkwardness temporarily reduced performance around PHV. Conclusions: Systematic participation in sports training can limit the phenomenon of adolescent awkwardness in the performance of strength and power. Hence, training programs should be tailored to maturity status, emphasizing skill development, strength training, and injury prevention. Future research should explore individualized training and the mechanisms underlying performance variability during the PHV period. Full article

Objective: Strength training has gained recognition as an effective method to enhance physical fitness in children and adolescents. Its benefits include improvements in muscular strength, aerobic capacity (VO₂max), and motor performance. However, the diversity in training protocols and participant characteristics across studies necessitates a comprehensive synthesis of the evidence. The aim of this paper was to analyse the influence of a strength training programme in young people aged 6 to 16 years on different aspects of physical fitness. Methods: A search was carried out in the EBSCO, Web of Sciences, and Scopus databases. A total of 634 articles were reviewed, and 22 were finally included in the meta-analysis of articles published between 2013 and 2023 in English or Spanish. Twenty-two studies met the inclusion criteria and were assessed using the AXIS and PEDro tools. Standardised mean differences (SMD) and 95% confidence intervals (CI) were calculated. The variables that were most frequently repeated as criteria for evaluating the effectiveness of strength training were the following: (1) strength of the lower/upper body muscles; (2) VO₂max; (3) sprint performance. Results: Strength training interventions produced statistically significant improvements in all analysed variables. Most effective programmes lasted between 6 and 12 weeks, with 2–3 sessions per week. VO₂max showed the greatest improvement, followed by upper and lower limb strength, and sprint performance. Heterogeneity ranged from low to moderate. Conclusions: Supervised strength training programmes can significantly enhance physical fitness in school-aged children and adolescents. While the included studies varied in design and duration, measurable improvements were commonly observed in interventions lasting at least 6–8 weeks. Future research should explore age- and maturity-related responses through subgroup analyses. Limitations include the exclusion of studies published after 2023 and the wide age range of participants without biological stratification. Full article

The present review summarizes the effects of manipulating different resistance exercise variables on jumps, sprints, and changes of direction (CODs) in soccer. Regarding jumps, moderate-to-high loads, full range of movement (ROM), non-failure sets, and a moderate training volume are recommended. Different external resistances like constant-load, flywheel, or elastic bands, as well as various movement velocities and select exercises, are equally effective. As for sprints, moderate-to-high loads, constant load or flywheel but not elastic resistances, movements performed at full ROM, non-failure sets, and moderate-to-high training volume might be more effective, while numerous movement velocities and exercises could be chosen. As for CODs, moderate-to-high loads, flywheel more than constant-load resistance, and a moderate-to-high total number of repetitions are recommended, while several movement velocities and exercises could be selected, though ROM needs investigation. The effectiveness of concentric-only vs. eccentric-only training on jumps, sprints, and CODs has not been investigated, while an external focus and inter-set rest > 2 min are theoretically preferable, albeit not proven. Importantly, high movement velocity is not a prerogative of effectiveness, and limited ROM is not associated with sport-specific patterns such as jumps. Practitioners in soccer may manipulate resistance exercise variables depending on the purpose. Full article

Background: Sprint performance is crucial in rugby, impacting offensive and defensive actions. Despite increasing research on team sports, specific sprint training guidelines for rugby remain limited. This review evaluates the effectiveness of various training methods to improve sprint performance in semi-professional and professional players. Objectives: To identify and assess the most effective training methodologies for improving rugby sprint performance and provide evidence-based recommendations for coaches. Methods: A systematic review adhering to PRISMA guidelines was conducted across PubMed, Web of Science, and SPORTDiscus, including studies published before November 2024. Eligible studies focused on Rugby Union, Rugby League, or Rugby Sevens players undergoing resistance-based or sprint-specific training for at least four weeks. Exclusion criteria included amateur players, athletes under 16, or interventions using advanced technologies. Methodological quality was assessed using the PEDro scale. Results: Twenty-six studies involving 644 rugby players were analysed. Training programmes ranged from 4 to 18 weeks (average: 8 weeks) and were categorised into resistance training, small-sided games, and sprint-specific methods. Resistance training combined with plyometrics and agility drills achieved the most significant sprint improvements. Small-sided games enhanced sprint performance by simulating game-like scenarios, while resisted sprint training showed notable results for short-distance acceleration but limited maximum speed gains. Conclusions: Rugby sprint performance improves through periodised training protocols incorporating resistance exercises, plyometrics, and sport-specific drills. Coaches should use small-sided games and resisted sprint training to target short-distance acceleration and agility. Further research should examine the long-term effects of these methods and their influence on match performance. Full article