High-frequency plyometric jump training (PT) may benefit tennis players, but little is known about how its weekly distribution affects performance and acute perceived soreness. The aim was to investigate the effects of PT, conducted at different weekly frequencies, on physical performance and muscle soreness in competitive tennis players. Eighteen competitive tennis players were randomly assigned to PT-1 (1 session/week) (n=9; age 17.0±2.0 yrs) or PT-3 (3 sessions/week) (n=9; age 19.0±3.9 yrs), both performing 180 jumps over 8 weeks. Countermovement vertical (CMVJ) and squat jumps (SJ), single-leg horizontal hop (SLHH), 10- and 20-m sprints, and a repeated change-of-direction (COD) test were measured pre- and post-intervention. Muscle soreness was recorded before and immediately after each PT session using a 7-point Likert scale. Both groups improved jump height, hop distance, sprint time, and repeated COD performance (p<0.05). No between-groups differences were noted for CMVJ (p=0.419), SJ (p=0.692), SLHH (p=0.512), 10- and 20-m sprints (p=0.658 and p=0.741), nor repeated COD performance (p=0.191). Distributing the same PT volume over three weekly sessions produces performance gains comparable to a single weekly session. However, the increase in muscle soreness was significantly lower in PT-3 than in PT-1 group. Higher-frequency, lower-dose PT may reduce acute muscle soreness perception while maintaining performance improvements.

Biomechanical analysis of femoral stress response during squatting: A combined multibody dynamics and finite element approach.

Introduction Football referees perform repeated sprints, rapid changes of direction, and frequent deceleration–acceleration actions that place high demands on balance, mobility, and neuromuscular control. Limitations in functional movement patterns may negatively influence movement efficiency and increase mechanical stress during match officiating. This study aimed to examine the effects of a 12-week unstable/compliant surface–based mobility exercise program on functional movement quality, as assessed by the Functional Movement Screen (FMS), in young male amateur football referees. Methods A total of 60 male amateur referees (experimental = 30; control = 30; age = 22.6 ± 1.3 years) participated in the study. Both groups continued their routine training, while the experimental group additionally performed mobility exercises on unstable and compliant surfaces (primarily BOSU-based drills) twice weekly for 12 weeks (45 ± 5 min/session). FMS tests were administered before and after the intervention. Data were analyzed using a 2 (group: experimental vs. control) × 2 (time: pre-test vs. post-test) mixed-effects ANOVA, with verification of normality through Shapiro–Wilk testing and visual inspection of residual distributions, and the group × time interaction was considered the primary indicator of intervention effectiveness. Results The mixed ANOVA revealed significant group × time interaction effects for Total FMS score (p < 0.001) as well as for Deep Squat (p = 0.004), Hurdle Step (p < 0.001, partial η 2 = 0.33), Active Straight Leg Raise (p = 0.043), Trunk Stability Push-up (p = 0.001), and Rotary Stability (p < 0.001). The control group showed minimal changes across all outcomes. Discussion These findings indicate that unstable/compliant surface–based mobility training can improve movement quality indicators measured by the FMS. Incorporating such exercises into referee conditioning programs may contribute to more efficient movement patterns and enhanced dynamic stability, with potential implications for physical preparedness during match officiating.

Muscle fiber type composition is a sports performance determinant, but its use in sports practice is hampered by the invasive muscle biopsy. We aimed to determine the best non-invasive method or combination of such methods to estimate muscle fiber type composition. We hypothesized that methods measuring different fiber type-specific characteristics, i.e., metabolism, power, contractility and endurance, would complement each other. Forty young, healthy and recreationally-to-competitively trained participants (20 men) underwent non-invasive tests and four muscle biopsies: two in the vastus lateralis and two in the gastrocnemius medialis. The average relative area occupied by type II fibers across the biopsies served as the criterion measure (multi-muscle FTarea%). On average, this was calculated based on the fiber type of ~5200 fibers and the cross-sectional area of ~1200 fibers per participant. Participants performed 30-m sprints, squat jumps, a Wingate with blood lactate measurements, isometric and isokinetic knee extensions, a maximal ramp incremental cycling exercise and underwent peripheral electrical stimulation of the quadriceps and a proton magnetic resonance spectroscopy scan to measure muscle carnosine. Multi-muscle FTarea% ranged from 21.2 to 60.1%. Many parameters were significantly associated with multi-muscle FTarea%, but post-Wingate blood lactate concentration showed the strongest correlation (r=0.67; p<0.001). A multiple linear regression model with sex, post-Wingate blood lactate, peak knee extension torque at 300°.s -1 scaled to upper leg lean mass, average vastus lateralis and soleus carnosine and singlet contraction time as predictors could explain 68% of the multi-muscle FTarea% variance, confirming our hypothesis. The proposed model which combines non-invasively measured parameters of metabolism, power and contractility can provide a reasonably accurate estimate of vastus lateralis and gastrocnemius medialis fiber type composition.

Background: Nutrition affects the athlete’s health and performance. Modern sport relies on data‑driven analytics that combine nutrition and performance, yet fencing lacks sport‑specific reference values, limiting data-driven approaches in fencing. Aim: This study seeks to (i) characterize the nutritional status of highly trained and elite Swiss fencers, and (ii) establish normative references for performance metrics in fencing. Methods: Sixteen Swiss fencers (mean age: 22.6 ± 4.0 years, female n = 8, highly trained n = 6, elite n = 10) will be assessed in three seasonal waves (fall 2025, spring 2026, summer 2026). Each timepoint involves assessment of body composition (bioelectrical impedance), dietary intake, selective biomarkers, and performance measures. Dietary intake is assessed using a prospective 4-day food log along with a newly developed retrospective digital food frequency questionnaire (G-ADI). Blood and urine biomarkers are collected with a commercial device assessing vitamins, minerals, fatty‑acid profiles, and oxidative‑stress markers. Performance is assessed by a test battery comprising countermovement jump (CMJ) and squat jump (SJ) measured on a force plate as well as a maximal incremental cycling test to determine aerobic endurance. In addition, a fencing‑specific change‑of‑direction and reaction time test is performed, consisting of 12 sprints interspersed with target hits on an electronic fencing target. Results: Preliminary descriptive statistics show that males weighed 76.2 ± 5.7 kg with 14.9 ± 1.4 % body fat, while females weighed 59.6 ± 3.4 kg with 18.3 ± 3.1 % body fat. Arm muscle mass was 7.3 ± 1.8% greater on the dominant side, confirming fencing‑related asymmetry. The G‑ADI indicated an average intake of 5.6 portions/day of protein‑rich foods, exceeding the 4 portions recommended in the Food Pyramid for Swiss Athletes (FPSA). Furthermore, 3.4 portions/day of fruits and vegetables fall short of the recommended 5 daily portions for this food group. Intake of carbohydrate-rich foods averaged 4.4 portions/day. Based on the FPSA, most fencers’ intake of carbohydrate-rich foods did not match training requirements. On average, serum 25‑OH‑D was 65.7 ± 13.4 nmol/L, falling below the athlete‑specific reference of 95 nmol/L in 79 % of fencers. Calcium averaged 96.9 ± 3.0 mg/L, exceeding the population-based upper limit (PBUL) of 96 mg/L in 64 % of fencers. The omega‑3 index was 3.3 ± 0.9 % and below the recommended 4–8 % in 85 % of fencers. Oxidized LDL-cholesterol measured 55.9 ± 18.1 U/L, surpassing the PBUL of 55 U/L in 33 % of fencers. The 8‑iso‑prostaglandin F2α biomarker was 97.9 ± 37.0 ng/mmol creatinine, exceeding the PBUL of 80 ng/mmol creatinine in 60 % of fencers. CMJ height averaged 0.402 ± 0.064 m (males) and 0.264 ± 0.026 m (females). A bilateral deficit of -20.2 ± 11.7 % was observed. Maximal oxygen uptake was 45.8 ± 7.0 ml·kg⁻¹·min⁻¹ (females 41.0 ± 5.5; males 50.5 ± 4.7). The fencing‑specific test produced mean decrement scores of 4.9 ± 1.8% for repeated sprint ability and 23.5 ± 7.3% for reaction time. Conclusion: This study provides preliminary normative values for body composition, nutritional status, and performance in fencing, offering a baseline for future interventions.

Introduction: Soccer is the most popular sport globally for both men and women. The functional movement screen (FMS) is a 7-part standardized tool created by experts to evaluate movement quality. This research compares FMS scores and performance between male and female soccer players. Materials and Methods: A total of 60 semi-professional soccer players (30 males and 30 females) participated in this study. All participants completed the FMS test, Y-balance test, Davies test, single hop for distance, and cross-over hop test. Between-group comparisons were performed using an independent t test for normally distributed variables and the Mann- Whitney U test for non-normally distributed variables. Results: There were no significant differences between male and female players in deep squat, hurdle step, in-line lunge, or overall FMS score (P&gt;0.05). However, significant differences were found in shoulder mobility, active straight leg raise, trunk stability push-up, and rotary stability (P&lt;0.05). Men performed better in trunk stability, while women excelled in shoulder mobility and active straight leg raise. Men outperformed women in the single-hop distance and the cross-over hop. In upper extremity performance, males performed better in the Davies test and dynamic balance in the superolateral direction, with no significant differences in other upper extremity dynamic balance directions. Conclusion: The study’s findings demonstrate the necessity of gender-specific training programs to enhance performance and reduce injury risk. According to the findings, it is recommended that flexibility and mobility exercises be implemented for male soccer players and that core stability and strength training be implemented for female soccer players

This study investigates the effects of 8 weeks of liquid protein supplementation on resistance-training adaptations in healthy, untrained college students. Thirty untrained male participants were randomized into two groups: a protein supplement (resistance training exercise (RTE) + protein) and a control (RTE). Both groups underwent resistance training exercises (RTE) three times per week for 8 weeks. The RTE + protein consumed a protein liquid supplement post-exercise, while the RTE consumed water. The results showed a higher degree of change in chest circumference (mean difference = 6.10 cm vs 3.36 cm), maximal bench press strength (mean difference = 16.00 kg vs 8.93 kg, P = 0.007) and maximal squat strength (mean difference = 42.33 kg and 27.32 kg, P = 0.018) in the RTE + protein group compared to the RTE group. Both groups demonstrated increases in thigh circumference, muscle mass, and maximal bench press and deep squat repetitions, but no significant differences were observed between the two groups. These findings suggest that post-exercise protein liquid supplementation can enhance the benefits of RTE on muscle strength and body circumference in young untrained adults. The study highlights the importance of post-exercise protein supplementation for beginners seeking to improve muscle performance, and future research should explore the long-term effects and optimal dosages of protein supplementation in different forms. This trial was registered with ChiCTR under the registration number ChiCTR2300076750.

Somatotype has been linked to physical performance in youth athletes, but its independent contribution to power development, particularly in relation to biological maturity, remains underexplored. This study examined whether somatotype and age independently influence neuromuscular performance in elite youth football players and whether these effects persist after normalization for body mass. A total of 106 elite male academy players aged 15 to 18 years were classified as mesomorphic or ectomorphic using the Heath-Carter method. Performance tests included vertical jumps from a squat position and with countermovement, lower-limb peak power (estimated via a validated field equation), and an index estimating stretch-shortening cycle efficiency. Relative power (W·kg-1) was also calculated to account for body-mass dependence. Analyses included multivariate and variance testing, to explore independent effects of somatotype and age. Mesomorphic players produced significantly higher power output than ectomorphic players; older athletes also exhibited greater power. No interaction was observed between somatotype and age group. However, when normalized to body mass, between-group differences were no longer significant, indicating that the apparent mesomorphic advantage reflected greater mass rather than superior neuromuscular efficiency. No significant somatotype effect was observed for the Elasticity Index (P=0.098). Logistic regression correctly classified 72.6% of somatotypes, but specificity for ectomorphs was very low (11.5%), indicating that power-based profiling is ineffective for identifying ectomorphic players. Somatotype and age independently influence power performance in elite youth football players. Nevertheless, relative power analysis demonstrated that morphological differences primarily underlie these effects. Power metrics alone lack diagnostic validity for morphological classification and should complement, rather than replace, anthropometric assessment.

Explosive power training is increasingly relevant for general fitness participants. While complex training effectively enhances strength and power in athletes, its practicality and efficacy for trained non-athletes using moderate loads and minimal equipment remain unclear. This study aimed to evaluate the effects of a practical complex training (CT) protocol-featuring moderate-load resistance and accessible plyometric exercises-on jump performance, sprint acceleration, and reactive strength in physically active young men. Thirty trained young males (≥ 1year of resistance and aerobic training) were randomly assigned to a complex training group (CTG, n = 15) or traditional resistance group (TRG, n = 15). Both trained 3 times/week for 6weeks. CTG combined moderate-load resistance and basic plyometrics (e.g., squat + box jump), while TRG followed load-matched resistance-only routines. Tests included squat jump (SJ), countermovement jump (CMJ), drop jump (DJ), reactive strength index (RSI), eccentric utilization ratio (EUR), five-repetition vertical jump (5RVJ), 100-m sprint with segmental splits, standing long jump (SLJ), and 25-m sled drag. Training load was monitored using heart rate-based Training Impulse (TRIMP) and Rating of Perceived Exertion (RPE). CTG showed no significant gains in CMJ or SJ performance (p > 0.05), but exhibited a significant improvement in EUR (p = 0.016, d = 0.76), with a notable between-group difference at post-test (p = 0.005, d = 0.92). In contrast, significant improvements were observed in DJ height (p = 0.023, r = 0.49), DJ power (interaction p = 0.0002, d = 0.51), and RSI (p = 0.031, d = 0.83). Sprint performance improved significantly in the 0-10m (p = 0.012, r = -0.54) and 20-30m (p = 0.016, d = 0.45) phases, with significant interaction effects observed for 100m total time (p = 0.0035, d = 0.41). No significant changes were noted in SLJ, 25m sled drag sprint, or 5RVJ metrics. A CT protocol using moderate loads and basic equipment can enhance reactive strength and sprint acceleration in physically active young men, offering a practical and accessible approach for performance gains in general fitness settings. Chinese Clinical Trial Registry (ChiCTR2500112099). Registration Date 10/11/2025 (Retrospectively registered).

BackgroundTranscranial direct current stimulation (tDCS) has been reported to enhance explosive strength in lower limb skeletal muscles. Nevertheless, findings regarding the impact of tDCS on jump performance remain inconclusive, potentially due to variations in stimulation montage and current intensity. Therefore, we aimed to elucidate the effects of multifocal tDCS on lower limb jump kinetics and neuromuscular adaptation.MethodsFourteen female collegiate basketball players were enrolled in a randomized, crossover, controlled trial. Each participant underwent three intervention sessions in a randomized sequence: 2 mA tDCS, 4 mA tDCS, and sham tDCS, all targeting the primary motor cortex (M1). After each stimulation session, countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), and surface electromyography (EMG) data were collected. Statistical analysis was performed using one-way repeated measures ANOVA.ResultsThe 4 mA multifocal tDCS condition produced a significant increase in jump height compared to baseline, sham, and the 2 mA condition. Similarly, the concentric impulse was markedly higher in the 4 mA group relative to all other conditions. Relative peak force was significantly improved in the 4 mA group versus baseline, and relative peak power was significantly greater under 4 mA tDCS compared to sham stimulation. The modified reactive strength index (RSImod) was also enhanced considerably following 4 mA tDCS, relative to both baseline and sham conditions. However, EMG analysis indicated that none of the tDCS interventions significantly affected the root mean square (RMS) values of lower limb muscle activation, including the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), semitendinosus/semimembranosus (SEM), medial gastrocnemius (MG), lateral gastrocnemius (GL), and tibialis anterior (TA).ConclusionMultifocal anodal tDCS at an intensity of 4 mA significantly improves lower limb jump performance in female collegiate basketball athletes. Integrating multifocal anodal tDCS into routine training regimens may serve as a practical and effective adjunct for enhancing performance in this population.

Reliability and profiling of physical performance tests in Australian Football League Women's (AFLW) athletes.

Effect of multicomponent and stability exercises on body composition, physical fitness, and functional movement capability in active older women: a non-randomized study.

ObjectiveKnee orthoses assist patients with joint instability, yet many passive designs provide limited energy dissipation and flexion-load regulation during high-demand activities. This study designed and validated a compact three-spring shock-absorption mechanism to provide quasi-passive flexion resistance, improve energy absorption, and redistribute loads in knee orthoses.MethodsA mechanical design and validation study was conducted combining analytical modeling, finite-element simulation, and pilot functional testing. The mechanism integrates two compression springs and one tension spring housed in an aluminum frame. Finite-element simulations (ANSYS Explicit Dynamics®) evaluated deformation, absorbed energy, and von Mises stress under dynamic loading over a 0-70° motion range, and were calibrated using experimental compression/tension tests of single and paired springs. Three functional prototypes were fabricated and evaluated by three adult volunteers using one-leg rise and deep-squat tasks, with perceived assistance recorded on a 100-mm Visual Analogue Scale (VAS) under institutional ethics approval.ResultsSimulated and experimental endpoint force and total deformation (L0 - Lf) showed close agreement, with relative deviations below 3%. For the evaluated configuration, the orthosis generated an estimated total passive flexion resistance of 70.54 Nm for two modules, corresponding to a case-specific 48.22% reduction in required flexion torque when referenced to a representative post-ACLR peak torque (146.30 Nm). Peak stresses remained below the yield strength of 6061-T6 aluminum, while the beam-base interface was identified as the durability-critical region. Functional testing yielded mean VAS scores of 36.67 ± 2.89 (one-leg rise) and 41.67 ± 5.77 (deep squat), indicating moderate perceived assistance.ConclusionsThe proposed multi-spring mechanism provides measurable quasi-passive resistance and withstands conservative high-flexion loading, supporting its feasibility as a compact assistive concept. These proof-of-concept results motivate further work on fatigue/wear assessment, multi-objective optimization, and larger clinical studies with objective functional outcomes.

Objectives. The aim of this study was to assess whether a warm-up routine incorporating plyometric exercises promotes greater improvements in jumping performance, power output, and neuromuscular responsiveness compared with warm-up strategies commonly used in volleyball practice. Materials and Methods. Twenty-four sub-elite female volleyball players (age: 16.3 ± 0.6 years; body mass: 58.7 ± 3.8 kg; height: 165.6 ± 6.8 cm) from a regional club performed three different warm-up protocols, each lasting 20 minutes: traditional warm-up (TWU), neuromuscular warm-up (NWU), and isometric warm-up (IWU). To minimize fatigue effects, three experimental sessions were conducted with 48-hour intervals. Following each warm-up protocol, participants were randomly assessed using the Squat Jump (SJ), Countermovement Jump (CMJ), Standing Long Jump (SLJ), Squat Jump–Block Jump (SJ–BJ), Repeated Countermovement Jump (RCMJ), and Drop Jump (DJ) tests. Results. Jump performance outcomes demonstrated significantly higher values (p &lt; 0.001) following the NWU protocol. Compared with IWU, TWU resulted in higher performance values in SLJ, SJ–BJ, RCMJ, and shorter ground contact time during the DJ test. Conclusions. Neuromuscular warm-up appears to be particularly effective in sports requiring explosive, high-speed actions, as it may directly enhance training quality and jumping performance during competition. The findings indicate that post-activation performance enhancement (PAPE) can be observed in Under-17 female volleyball players when appropriate warm-up exercises are applied. This study provides practical insights into warm-up strategies for youth volleyball clubs with limited access to resistance training equipment.

This study examined whether consuming a (poly)phenol-rich food before strenuous muscle-damaging exercise can modify post-exercise markers of inflammation and oxidative stress. Using a double-blinded, randomised, placebo-controlled, between-subjects design, 26 recreationally active males (n=15) and females (n=11) consumed higher-(poly)phenol (H-POL) foods (dates, dark chocolate, pomegranate; 285.1mg/day) or lower-(poly)phenol foods (L-POL) (cereal bar, milk chocolate, sports drink; 88.3mg/day) for 3days before, and then 30min before, strenuous exercise (100 drop jumps, 50 squat jumps). A range of blood markers associated with inflammation (total and differential leukocytes, interleukin (IL)-6, IL-10, IL-1β, IL-2, IL-4, IL-12, tumour necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), granulocyte colony-stimulating factor), and oxidative stress (glutathione peroxidase (GPX), 4-hydroxynonenal (4-HNE), and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG)) were quantified pre, immediately post, 1 and 2h post-exercise. One hundred and nineteen plasma (poly)phenol metabolites were measured pre, immediately post and 1h post-exercise. Total plasma (poly)phenol concentrations were greater in the H-POL vs. L-POL intervention, peaking 1h post-exercise (H-POL: 239.5±87.8µM vs. L-POL 58.9±33.8µM; P<0.001). There were interaction effects for IL-10 and TNF-α but no differences with post hoc tests. Urinary 8-OHdG excretion was higher in H-POL vs L-POL (condition effect; P<0.001), whereas erythrocytes GPX activity was higher in the L-POL vs. H-POL (condition effect; P<0.001). A (poly)phenol food intervention before exercise increased total plasma (poly)phenol concentrations but had limited and inconsistent effects on markers of inflammation and oxidative stress in the 2h after strenuous exercise.

Understanding the long-term effectiveness of warm-up strategies is essential for enhancing neuromuscular performance in youth soccer players. This study examined the long-term effects of integrating squat exercises into the final phase of the warm-up over nine weeks on sprint, jump, change-of-direction (COD), and aerobic performance in youth soccer players. Twenty-four male U17 players were randomly assigned to either a squat-based warm-up (experimental group [EG]) or a rondo-based warm-up (control group [CG]). The EG trained twice weekly using 3–4 sets of 4–12 repetitions at progressively increasing intensities (50–85% of 1-RM). Performance was assessed pre- and post-intervention using 10 and 30 m sprint, squat jump (SJ), countermovement (CMJ), standing long jump (SLJ), 5-jump (5JT), T-half (COD), and VAMEVAL tests. The EG showed small to large significant gains in sprint (10 m: −2.21%, Cohen’s d [d] = 1; 30 m: −1.6%, d = 0.58), jumping (SJ: +9.29%, d = 1.23; CMJ: +12.08%, d = 1.83; SLJ: +7.14%, d = 0.8; 5JT: +2.33%, d = 0.32), and COD (−1.41%, d = 0.32), while aerobic endurance showed no significant change (p > 0.05). The CG showed no significant improvements (p > 0.05). Overall, integrating brief, progressive squat exercises at the end of warm-ups twice weekly led to chronic improvements in explosive neuromuscular performance, with minimal impact on aerobic endurance.

ABSTRACTBackgroundPhenylcapsaicin (PC) may enhance high-intensity exercise performance by reducing perceived exertion, increasing mechanical output, and limiting muscle damage, making it potentially beneficial for CrossFit® (CF) athletes.ObjectiveTo examine the acute effects of PC supplementation on performance, recovery, and metabolic responses during a CF session.MethodsThis study had a randomized, triple-blind, placebo-controlled crossover design. Fifty CF-trained athletes (50% women) ingested either 2.5 mg of PC or a placebo (PLA) 45 minutes before a standardized CF session, including a warm-up, weightlifting block, and WOD. Delayed-onset muscle soreness (DOMS) was assessed 24- and 48-hours post-session. Countermovement jump (CMJ) was evaluated pre- and post-session, while a deep squat at 70% 1RM was performed post-session. Throughout the session, heart rate, capillary lactate, rating of perceived exertion (RPE), and perceived recovery status (PRS) were monitored.ResultsCompared to PLA, PC improved squat performance at 70% 1RM in both load and repetitions (P ≤ 0.035), attenuated the decline in CMJ (P < 0.001), and maintained weightlifting performance over time (P interaction = 0.011), with significantly higher load in round 9 (P = 0.030). No differences were observed during the WOD (P interaction ≥ 0.826). DOMS was significantly lower in the PC group at both 24 h and 48 h (P = 0.030), while no group differences were found for lactate, RPE, PRS, or heart rate (P interaction ≥ 0.340). Analysis stratified by sex showed that PC reduced CMJ loss in men (P = 0.043) and increased squat load in women (P = 0.021).ConclusionIn conclusion, acute PC supplementation enhances performance and recovery in CF athletes.

Muscular strength plays a crucial role in sports performance and is often evaluated using vertical jump tests such as the Squat Jump (SJ) and Countermovement Jump (CMJ). Measurements based on flight time (FT) assume that takeoff and landing postures are identical, yet differences in ankle position can introduce systematic errors. This study examined whether dorsiflexion (DF) or plantarflexion (PF) of the ankle during the flight phase affects jump height. Forty-three active university students completed four repetitions each of SJ and CMJ under DF and PF across two sessions. Jump heights were recorded using a Chronojump-Boscosystem platform. No significant difference was observed in SJ between DF and PF, while CMJ heights were consistently higher under DF (DF: 28.29 cm ± 7.7 cm vs. PF: 27.08 cm ± 7.03 cm, p = 0.001; d = 0.16). Notably, the effect of DF appeared more pronounced in CMJ, suggesting that higher jumps are more sensitive to postural variations. These findings could suggest that DF can artificially increase jump heights as measured on a jump platform, without reflecting true improvements in force production. Coaches and practitioners should interpret FT-derived data with caution, particularly for higher jumps. Future research combining precise motion capture with force platforms could directly track center-of-mass changes and validate this mechanism.

Youth soccer requires an integrated approach combining technical–tactical, physical, and psychological components to enhance performance and long-term engagement. Although Repeated Linear Sprint Training (LRST) and Repeated Change of Direction Speed (RCOD) training are widely used to improve fitness, direct comparisons of their effects on physical performance and perceptual responses in adolescent players remain limited. This study compared the effects of an 8-week LRST versus RCOD training program on physical performance, perceived exertion, and enjoyment in youth soccer players. Twenty-six male players were randomly assigned to an LRST group (n = 13) or an RCOD group (n = 13). Both groups completed two weekly sessions of their assigned training in addition to regular soccer practice. Pre- and post-intervention assessments included acceleration and sprint speed, change-of-direction (COD) performance (T-Half Test [THT], Illinois Agility Test [IAT]), lower-limb power (Five-Jump Test [5JT], Squat Jump [SJ], Countermovement Jump [CMJ]), and endurance-intensive fitness. Enjoyment and session-RPE were recorded after each training session. Both groups improved across all physical measures (main effect of time, p < 0.0001). Significant time × group interactions favored RCOD for THT (~1.6%), IAT (~1.1%), 5JT (~2.3%), CMJ (~5.2%), and SJ (~6.3%), with no overall main effect of group. Enjoyment was consistently higher in the RCOD group (p < 0.0001), while session-RPE did not differ between groups. In youth soccer, both LRST and RCOD effectively enhance physical performance. However, RCOD appears more effective for improving pre-planned COD and explosive performance while eliciting greater enjoyment without increasing perceived exertion. Incorporating structured RCOD training alongside linear sprint work may represent a practical strategy to optimize physical development and sustain player engagement.

Conflicting findings have been reported about effects of transcutaneous spinal direct current stimulation (tsDCS) on jumping performance, as transabdominal tsDCS was shown to enhance maximum jumping height while spine-shoulder did not. The aim of the study was to evaluate effects of anodal transabdominal tsDCS in prone lying on jumping height in less experienced (LEJ) and experienced (EJ) jumpers. Participants from LEJ (physical education students, 13 men and 10 women) and EJ (volleyball players, 13 men and 10 women) were subjected to a single 15-min session of anodal transabdominal tsDCS. Maximum vertical jumping height was measured during two sets of maximum squat jumps (SJs) and counter movement jumps (CMJs) performed in randomized order immediately, 30- and 60-min post stimulation. One set was composed of 3 jumps. There was 3-min break between the sets and 1 min rest between the jumps. Two-way analysis of variance did not show the effect of interaction between the stimulation and time on jumping height during SJ (F2,44 = 1.629; p = 0.208) and CMJ (F2,44 = 1.304; p = 0.282) in EJ, as well as during SJ (F2,44 = 1.346; p = 0.271) and CMJ (F2,44 = 0.228; p = 0.747) in LEJ. TsDCS does not improve jump height in either squat or countermovement jumps in recreationally active and professional volleyball players. The results question the use of single session of transabdominal tsDCS in recreational or sports training to improve jumping performance.