The objective of the study was to compare conventional biomechanical outcomes, movement regularity, and local dynamic stability among habitual rearfoot strikers during acute non-rearfoot-strike adoption (HRFS-AN) and after 12 weeks of gait retraining (HRFS-GR), and habitual non-rearfoot strikers (HNRFS). Thirty-three male recreational runners enrolled. Analyses included 13 habitual rearfoot strikers assessed during acute NRFS adoption and after 12 weeks of gait retraining, together with 14 HNRFS. Participants ran on a treadmill at 9 km·h⁻1 while ground reaction forces and lower-limb kinematics were recorded. Coefficient of variation (CV), sample entropy (SampEn), and largest Lyapunov exponent (LyE) were used to characterize discrete kinematic variability, temporal regularity, and local dynamic stability, respectively. Runners in all three states adopted an NRFS pattern. HRFS-AN showed a more anterior foot strike than HRFS-GR and HNRFS. Peak vertical ground reaction force and most spatiotemporal and discrete kinematic outcomes did not differ among states; selected joint angle and CV outcomes differed, while VILR and VALR were lower in HRFS-AN than in HRFS-GR. Compared with HRFS-AN, HRFS-GR and HNRFS exhibited lower SampEn for sagittal-plane knee and ankle motion and vertical COM motion, and lower LyE for sagittal-plane knee and vertical COM motion. Compared with HNRFS, HRFS-GR exhibited higher SampEn for sagittal-plane knee and transverse-plane hip motion and higher LyE for sagittal-plane knee and coronal-plane hip motion. Most conventional biomechanical outcomes were similar among states; however, HRFS-AN exhibited a more anterior foot strike than HRFS-GR and HNRFS, as well as lower VILR and VALR than HRFS-GR. Compared with acute adoption, the retrained state showed greater regularity and local dynamic stability in selected knee, ankle, and COM trajectories, although selected differences from HNRFS remained. These findings suggest that a gradual 12-week gait-retraining programme may be an appropriate approach for transitioning habitual rearfoot strikers to NRFS.
The instep kick is a frequently performed, high-load soccer skill that requires precise intermuscular coordination around ball contact. This study compared time-frequency activation patterns between elite and amateur male soccer players across two kicking phases and identified the key time windows and dominant muscle contributions. Surface electromyography was recorded from seven muscles of the kicking leg in 15 elite and 15 amateur players: rectus femoris, vastus medialis, vastus lateralis, biceps femoris, tibialis anterior, medial gastrocnemius, and lateral gastrocnemius. The instep kick was divided into Phase 1, from maximum hip extension to ball contact, and Phase 2, from post-contact follow-through to maximum hip flexion. Morlet wavelet analysis was used to generate time-frequency intensity maps. Global principal component analysis was then performed to extract PC1 to PC6, and between-group differences in PC score trajectories were assessed using SPM1D independent-samples t tests, with significance evaluated under a Bonferroni adjusted threshold for the 12 PC phase comparisons. In Phase 1, PC3 showed a significant between-group difference at 54-75% of the normalized time (peak t = 7.62, p < 0.001, Hedges’ g = 2.96), with higher scores in the elite group. In Phase 2, PC1 differed significantly between groups at 60-70% of the normalized time (peak t = -9.88, p < 0.001, Hedges’ g = -2.03), with higher scores in the amateur group. Elite players showed a more temporally focused pre-contact activation pattern centered on mid-frequency components of the biceps femoris, whereas amateur players showed greater reliance on higher-frequency components of the medial gastrocnemius during the post-contact follow-through. These findings suggest that skill-level differences are expressed as phase-specific redistribution of muscle and frequency-band activity within critical time windows, rather than as a simple global difference in activation magnitude.
Hydrogen-rich water (HRW) supplementation has been proposed to exert anti-fatigue effects during exercise; however, its impact on exercise performance and autonomic nervous system (ANS) function during repeated sprinting remains unclear. The aim of this study was to examine the effects of acute pre-exercise HRW ingestion on repeated sprint performance, ANS regulation, and blood lactate concentration. This randomized, single-blind, placebo-controlled crossover study included 13 male university athletes (23.9 ± 2.0 years). Each participant completed two sessions of 7×6-second all-out cycling sprints interspersed with 30-second recovery intervals, with a one-week washout period between sessions. Critical flicker fusion frequency, heart rate, heart rate variability (HRV), and blood lactate were assessed at baseline, during exercise, and at 0-5 min and 10 min post-exercise. Compared to the placebo trial, the HRW trial demonstrated significantly higher average power output (d = 0.61) and significantly lower total work decrement and fatigue index (d = 0.62; d = 0.64). Post-exercise HRV recovery was significantly accelerated in the HRW trial, including RMSSD (d = 0.62), LF/HF ratio (d = 0.82), SampEn (d = 0.79), and DFAα1 (d = 0.79). Blood lactate at 3 min post-exercise was approximately 1 mmol/L lower in the HRW trial (d = 0.64). These findings suggest that acute HRW ingestion attenuates the decline in power output, accelerates ANS recovery, and enhances lactate clearance following repeated sprint exercise.
The aim of this study was to provide a comprehensive comparison of training modalities for countermovement jump (CMJ) performance in soccer players using a network meta-analysis (NMA). PubMed, Web of Science, Embase, EBSCO, and the Cochrane Library were searched up to November 2025. Randomized controlled trials (RCTs) involving healthy soccer players, evaluating structured training interventions against comparator training or control conditions, and reporting CMJ height outcomes were included. A random-effects NMA was performed to estimate mean differences (MDs) with 95% confidence intervals (CIs), and interventions were ranked using P-scores, integrating both direct and indirect evidence. Subgroup analyses were conducted according to age, sex, and competitive level. Twenty-nine RCTs (n = 450) were included. The network showed moderate heterogeneity and no evidence of significant inconsistency. Combined training (CBT) was ranked highest in effect estimates in CMJ performance compared with traditional soccer training (TST) (MD = 4.92, 95% CI: 3.02-6.83, P-score = 0.98), followed by flywheel resistance training (FT) and plyometric training (PT), whereas other interventions did not demonstrate significant improvements. Subgroup analyses indicated that CBT ranked highest in males, youth, and Tier 2 players; PT ranked highest in females and adults; and FT ranked highest in highly trained players. Given the limited sample sizes, limited statistical power, and the fragmented nature of some subgroup comparisons, these findings should be interpreted cautiously. The network showed moderate heterogeneity (I2 = 32.4%) and no evidence of significant inconsistency. The certainty of evidence was generally low to moderate according to the CINeMA assessment. Directness of evidence was generally high across comparisons, although several key contrasts (e.g., CBT vs FT and FT vs PT) relied partly on indirect evidence within the network. Although the highest-ranked interventions (CBT, FT, and PT) were supported primarily by direct comparisons with TST, several active-active contrasts relied partly on indirect estimates. The reliability of the intervention rankings depends on similarity in participant characteristics, intervention dose, outcome measurement, and control conditions.
Contrast heat-cold showering is popular for recovery, but multisystem evidence and persistence after cessation remain unclear. To evaluate whether a 4-week post-training contrast heat-cold shower intervention produces an integrated recovery profile across four domains (autonomic, endocrine, perceptual, and microvascular) rather than testing a single isolated physiological pathway, across baseline (T0), post-intervention (T1), and 2-week wash-out (T2). Sixty combat-sport athletes were randomized to contrast showers (10 min alternating warm 38-40°C and cold 13-15°C) or an active thermoneutral-shower comparator (10 min, 32-34°C) after training for 4 weeks. Primary analyses were per-protocol (≥ 75% compliance; n = 57), with intention-to-treat sensitivity analyses. Outcomes were Total Quality Recovery (TQR), morning salivary cortisol (two mornings averaged), resting HRV, and post-occlusive reactive hyperemia (PORH). From T0 to T1, favorable between-group changes were observed for resting HR (ΔΔ -2.10 bpm, 95% CI -2.24 to -1.96; g -0.65; p < 0.001), lnRMSSD (ΔΔ 0.123 log units, 95% CI 0.108 to 0.137; g 0.74; p < 0.001), with similar T1 effects for RMSSD and SDNN, and TQR (ΔΔ 0.61 points, 95% CI 0.27 to 0.95; g 0.80; p < 0.001). These T1 autonomic and perceptual changes were not maintained at T2 (all T2-T0 ΔΔ p > 0.05). Cortisol and PORH-derived outcomes showed no statistically clear between-group differences at T1 or T2 (all p > 0.05). Compared with thermoneutral showering, 4 weeks of post-training contrast heat-cold showering produced short-term favorable between-group changes in autonomic regulation and perceived recovery, but not in morning cortisol or PORH-derived microvascular reactivity. These effects were not maintained after wash-out; therefore, causal attribution to the shower intervention alone and claims of persistent physiological adaptation should be made cautiously. Trial registration: ISRCTN15418049.
The aim of this study was to examine the reliability of peak force (PF) and rate of force development (RFD) from the Isometric Mid-Thigh Pull (IMTP) in 59 male basketball players from a Japanese professional club's youth academy classified into three age categories (U12: n = 18, U15: n = 27, and U18: n = 14). Each athlete completed three IMTP sessions, from which PF and mean RFD were calculated over time intervals of 0-50, 0-100, 0-150, 0-200, and 0-250 ms. Within-session and between-day reliabilities were evaluated using the intraclass correlation coefficient (ICC), coefficient of variation (CV), and standard error of measurement (SEM). PF demonstrated consistently high reliability across all age categories for both within-session and between-day analyses (ICC 0.77-0.98, CV 3.4-8.2%), with small SEM values (7.65-91.86 N, 0.60-4.13%) indicating limited measurement error. In contrast, RFD displayed poor reliability in shorter time windows (0-50 and 0-100 ms; ICC < 0.50), particularly in categories U12 and U15. Although longer time windows (0-150 and 0-250 ms) achieved higher reliability (ICC > 0.75) and lower SEM values than those previously reported, the CV values remained high (10.7-34.8%). Such a large variability may obscure true performance changes. Consequently, the PF is recommended as a robust metric for young athletes across all age groups. In contrast, the current protocol limits the ability of RFD to accurately detect individual changes. Therefore, RFD requires careful interpretation and protocol modifications, such as extended familiarization, to improve stability and precision.
The objective of this study was to examine the effects of repeated-sprint training (RST) with varying bout durations on the physical fitness adaptations of young male volleyball players. Forty athletes were randomly allocated to one of three intervention groups performing RST with varying bout durations and similar repetition volumes, all executed at maximal effort. The 3-sec group (n = 10) completed two sets of 30 bouts, the 6-sec group (n = 10) performed two sets of 15 bouts, and the 9-sec group (n = 10) carried out two sets of 10 bouts, each adhering to a 1:3 work to rest ratio. An active control group (n = 10) engaged solely in regular volleyball training without the RST intervention. Physical fitness measures-including countermovement vertical jump (CMVJ), 10-m and 20-m linear sprints, T-test change-of-direction speed (T-CODS), reactive strength index (RSI), and the Wingate anaerobic power test-were assessed pre- and post-a 6-week training intervention (i.e., 18 sessions). All RST groups showed significant post-intervention improvements in physical fitness (main effect of time, p = 0.001), with greater adaptations compared with the control group and effect sizes ranging from small to very large. The 3-sec bout group demonstrated greater gains in CMVJ, 10-m and 20-m sprint performance, RSI, and peak power output compared with the 9-sec group (all, p < 0.05). Conversely, the 9-sec group exhibited superior adaptations in T-CODS and mean power output relative to the 3-sec group (all, p < 0.05). In conclusion, the 3-sec group experienced greater enhancements in explosive and sprint performances, while the 9-sec group showed superior gains in change of direction and mean power output. These findings indicate that manipulation of sprint-bout duration in RST can be used to optimize distinct performance adaptations in young volleyball players.
The purpose of this study was to investigate the effects of low-load blood flow restriction (BFR) training on lower limb kinematics during the fencing lunge, quadriceps strength, and balance in collegiate fencers. Sixteen collegiate sabre and epee fencers were randomly assigned to either a BFR group (n = 8) or a general leg extension (GLE) group (n = 8). Both groups performed 6 weeks of leg extension training. The BFR group trained at 30% of 1 repetition maximum (1RM) and the GLE group at 70% of 1RM. Due to dropouts, data from 14 participants were included in the final analysis. Primary outcomes were lower limb kinematics during three defined phases of the fencing lunge, quadriceps isometric strength, and static balance, assessed before and after the intervention. Between-group comparisons of change scores (Δ) were evaluated using effect sizes (Rank-biserial r) with 95% confidence intervals (CIs). Between-group Δ comparisons revealed small-to-large effect sizes favoring BFR across rear leg kinematic variables in all fencing lunge phases (r = 0.24-0.52). The largest effect was observed in rear leg hip flexion angle during Phase 3 (r = 0.52, 95% CI: -0.01 to 0.83). Significant between-group differences were found in front leg knee flexion angle during Phase 2 (p = .043) and rear leg hip extension angular velocity during Phase 3 (p = .029). Both groups showed significant increases in rear leg quadriceps strength (p < .05), with no meaningful changes in static balance. These kinematic improvements are functionally relevant, as greater rear leg hip flexion and faster angular velocity during the fencing lunge are associated with increased propulsive force and more effective lunge execution in competitive fencing. Preliminary evidence suggests that low-load BFR training may produce small-to-large effects on rear leg kinematics during the fencing lunge and may enhance quadriceps strength, providing a safe and practical alternative to high-load training for improving fencing performance.
Objective:This randomized controlled trial compared the effects of 1v1 and 3v3 basketball small-sided games (SSGs) on body anthropometric-related outcomes and physical fitness in sedentary female college students. Methods:Sixty-three sedentary female university students aged 18-21 years were randomized to 1v1 SSGs (n = 21), 3v3 SSGs (n = 21), or a non-training control group (n = 21) for 8 weeks. Training was performed three times per week, with each 60-min session including 40 min of SSG play. Outcomes were assessed at baseline, week 4, and week 8. All randomized participants completed the scheduled assessments, with no missing outcome cases. Adherence was 94.5% in the 1v1 group and 92.8% in the 3v3 group. The primary outcome was 20-m multistage fitness test distance. Secondary outcomes included body mass, body mass index, waist circumference, hip circumference, waist-to-hip ratio, the sum of skinfold thicknesses, handgrip strength, vertical jump height, and standing long jump distance. Linear mixed-effects models including group, time, and group × time were used to estimate longitudinal intervention effects. Results:The primary outcome improved more in both intervention groups than in the control group. The 20-m multistage fitness test distance increased by 29.1% in the 1v1 group and 35.3% in the 3v3 group, compared with 1.1% in the control group; the model-estimated differences in baseline-to-week 8 change versus control were 120.95 m for 1v1 and 151.43 m for 3v3, with both Holm-adjusted p values < 0.001. Body mass decreased by 6.8% in the 1v1 group and 8.2% in the 3v3 group, compared with 0.8% in the control group. The corresponding differences in baseline-to-week 8 change versus control were -3.45 kg for 1v1 and -4.18 kg for 3v3, both with Holm-adjusted p values < 0.001. The sum of skinfold thicknesses decreased by 10.6% in the 1v1 group and 12.2% in the 3v3 group, compared with 0.4% in the control group (p values < 0.001). Secondary fitness outcomes also improved more in the intervention groups than in the control group, including handgrip strength, vertical jump height, and standing long jump distance. The 3v3 format showed larger exploratory gains than 1v1 in vertical jump height and standing long jump distance, whereas direct between-format differences for multistage fitness test distance and handgrip strength were not statistically significant. Conclusions:Eight weeks of recreational basketball SSGs improved cardiorespiratory fitness, several adiposity-related indicators, and neuromuscular fitness in sedentary female college students. These findings support basketball SSGs as a reasonable university-based exercise strategy, although between-format comparisons should be interpreted cautiously because they were exploratory. Future studies should test these formats in larger multicenter samples, include longer-term follow-up, and incorporate dietary/free-living activity monitoring and direct training-load measures to clarify sustainability, mechanisms, and format-specific effects.
Performance fatigability during the 30-s sit-to-stand (STS) test is not well characterized despite its potential to detect early functional decline. Therefore, this study aimed to quantify temporal changes in power, trunk flexion and movement subphase durations during the 30sSTS, and to examine differences by age and sex. 93 middle-aged adults (50 males and 43 females; mean age 60.5 ± 3.0 years) and 102 older adults (48 males and 54 females; mean age 71.5 ± 5.0 years) performed a 30sSTS. Inertial measurement units (IMUs) mounted over the L4/L5 vertebral level were used to capture sit-to-stand power, trunk flexion and subphase durations in the first and last 10 s. Linear mixed-effects models evaluated temporal changes and group effects. Mean power declined (-11.9 W, d = -0.66), trunk flexion increased (+1.35°, d = 0.42), sit-to-stand duration lengthened and stand-to-sit duration decreased throughout the test (all p < 0.001). The within-test decrease in stand-to-sit duration was less pronounced in older compared to middle-aged adults (d = 0.42, p = .039). Older adults generated less power and spent more time in all subphases (p < 0.05). Females produced less power and greater trunk flexion (p < 0.001). The 30sSTS captures modest performance fatigability; but longer protocols may better reveal clinically meaningful decline. Future research should investigate mobility-limited individuals or examine associations with functional outcomes (frailty, mobility, balance) to provide additional insight.
The objective was to determine the test-retest reliability and concurrent validity of a drone system in comparison to a radar device. Seventeen male collegiate soccer players participated in two maximal 30-meter sprint runs. The test-retest reliability of the drone system was evaluated using intraclass correlation coefficients (ICC3,1), coefficient of variation (CV%), and standard error of measurement (SEM). Subsequently, the systematic bias and consistency of the two devices on various force-velocity (F-V) variables (e.g., maximal velocity [Vmax], theoretical maximal velocity [V0], theoretical maximal horizontal force [F0], the slope of the F-V relationship [SFV]) were evaluated using linear mixed model (LMM) and Bland-Altman analysis. The drone system demonstrated moderate to excellent test-retest reliability across all variables (0.59 ≤ ICC ≤ 0.95; CV% < 10%). While LMM analysis detected significant systematic differences for Vmax (p = 0.013) and V0 (p = 0.012), Bland-Altman analysis confirmed high practical agreement with minimal bias (≤ 1.12%) and narrow limits of agreement (LoA < 10%). Pmax, split times (T5m-T20m) and average accelerations (A10m-A20m) demonstrated greater consistency (%Bias ≤ 0.76%) with no significant systematic bias (p > 0.05). Conversely, early-acceleration and model-derived metrics (Tau, Amax, F0, SFV) exhibited significant bias (p ≤ 0.028) and wide LoA exceeding 10% (e.g., F0: -13.37% to 8.56%; SFV: -11.54% to 18.18%). In conclusion, although the drone system exhibits high monitoring value in the maximum speed phase, early-acceleration metrics (Amax, F0, and T5m) should be interpreted with caution for individual-level monitoring. The tracking instability during the early acceleration phase necessitates further algorithm optimization.
This study aims to develop a predictive model for alertness levels in elite shooting athletes by analyzing heart rate variability (HRV) dynamics under simulated competitive stress. 83 national-level shooting athletes completed a 60-minute Psychomotor Vigilance Task (PVT) protocol designed to mimic the sustained attentional demands of a competition, while HRV data were continuously recorded. Pearson correlation analysis identified HRV features associated with behavioral performance. Key predictors were selected via recursive feature elimination with Random Forest. Four machine learning algorithms-Support Vector Machine (SVM), Random Forest (RF), XGBoost, and AdaBoost-were employed to construct classification models for alertness. Model performance was evaluated using accuracy, precision, recall, F1-score, and the area under the ROC curve (AUC). SHAP analysis was applied to interpret feature contributions. The binary classification framework (optimal vs. sub-optimal alertness) demonstrated superior reliability over multi-class approaches. The AdaBoost model achieved the best performance, with an accuracy of 0.75, an F1-score of 0.73, and an AUC of 0.77. SHAP analysis revealed that the very low frequency percentage (VLF%) was the most critical predictor, followed by the SD2/SD1 ratio. Notably, elevated VLF% values were associated with lower alertness levels. The binary classification model, integrating key HRV indices (notably VLF%) with the AdaBoost algorithm, can effectively distinguish alertness levels in shooting athletes during simulated competitive stress. This approach provides a validated, non-invasive tool for objective psychophysiological monitoring in training, offering actionable insights for pre-competition readiness assessment.
To evaluate and compare the effects of six exercise interventions on sprint performance and vertical jump height in soccer players using a systematic review and network meta-analysis (NMA). A comprehensive literature search was conducted across PubMed, Embase, the Cochrane Library, Web of Science, and SPORTDiscus for randomized controlled trials (RCTs) published from January 2000 to 30 September 2025. Thirty-one eligible studies were included, covering Traditional Strength Training, Plyometric Jump Training, Speed Training, Endurance Training, Flexibility Training, and Regular Training. A frequentist random-effects network meta-analysis was conducted. Outcomes were pre-specified hierarchically, with sprint performance and vertical jump height as co-primary outcomes and COD and 1RM as secondary outcomes; secondary outcomes were interpreted as supportive rather than primary evidence. Traditional Strength Training was most effective for 5-m sprint performance (SUCRA = 99.8%; MD =- 0.09 s, 95% CI:-0.11 to-0.07), 20-m sprint performance (SUCRA = 89.9%; MD =-0.13 s, 95% CI:-0.20 to-0.06), and squat jump height (SUCRA = 86.2%; MD = 4.40 cm, 95% CI: 2.07 to 6.74). For the 30-m sprint, Speed Training ranked highest by SUCRA (74.2%), but the comparison with Regular Training was not statistically significant (MD =-0.16 s, 95% CI:-0.34 to 0.01). For the 40-m sprint, no intervention showed a statistically significant advantage over Regular Training. Among the prespecified co-primary outcomes, Traditional Strength Training appears to provide the most consistent benefits for short-sprint acceleration (5-20 m) and vertical jump performance in soccer players. Evidence for 30-40 m sprint performance was uncertain, and secondary outcomes (COD and 1RM) should be interpreted as supportive rather than as the primary basis for overall effectiveness claims. These findings support prioritizing strength-oriented training when short-sprint acceleration and vertical jump performance are key goals; however, the implications should be interpreted cautiously because certainty varied across comparisons and residual uncertainty remains. The protocol for this systematic review was prospectively registered in PROSPERO (CRD42024608868).
This study aimed to investigate the effects of 10-week interventions of polarized training (POL), high-intensity interval training (HIIT), and threshold training (THR) on cardiorespiratory fitness (CRF) and cardiometabolic risk factors in untrained, healthy, young obese females. A total of 40 obese, untrained females volunteered to participate in the study and were randomly allocated to four equal groups: POL, HIIT, THR, and a control (CON) group. Training intensity was prescribed relative to ventilatory thresholds (VTs) and categorized into three zones: Zone 1 (Z1; 95% VT1), Zone 2 (Z2; 50% to 95% VT2), and Zone 3 (Z3; 90% VO2max). All the training groups performed similar training loads (66% to 93% heart rate max) and the weekly intensity distribution was 75% Z1 and 25% Z3 for POL, 100% Z3 for HIIT, and 50% Z1 and 50% Z2 for THR. CRF, glycemic and lipid profiles, body composition, and cardiovascular variables were assessed before and after the 10-week intervention. After the intervention, total body mass, fat mass, heart rate, fasting glucose, cholesterol, LDL and triglyceride decreased in all exercised-groups (time effect: p < 0.001). In addition, the VO2max, VT1, VT2, Qmax and SVmax increased in all exercised-groups (time effect: p < 0.001) following the 10-week intervention period. Moreover, the POL group showed more adaptive responses than the HIIT and THR training modalities for the changes in the CRF, glycemic and lipid profiles, body composition, and HR (interaction effect: p ≤ 0.002) after the 10-week training. In summary, aerobic training models characterized by different intensity distributions are effective in improving CRF, cardiometabolic risk factors, and body composition. However, compared with HIIT and THR, POL elicited superior adaptations across a broader range of CRF and cardiometabolic variables. Collectively, these findings indicate that polarized volume training represents an effective non-pharmacological strategy for simultaneously enhancing CRF and reducing cardiometabolic risk in young, untrained women with obesity.
Exercise-induced hypertension (EIH) is associated with elevated risks of arrhythmia, coronary artery disease, arterial stiffness, and sudden cardiac death. Blood flow restriction (BFR) training has been proposed as a non-pharmacological intervention. This study aimed to evaluate whether changes in cardiovascular biomarkers accompanied hemodynamic improvements following BFR training in middle-aged runners with EIH. This secondary analysis included 28 male runners with EIH (mean age: 57.4 ± 6.5 years) from a prior cohort applying the same BFR training protocol. Participants exhibited a maximal systolic blood pressure ≥210 mmHg during graded exercise testing (GXT) and were assigned to a BFR training group (BFRTg, n = 16) or a control group (non-BFRTg, n = 12). BFR training was performed twice weekly for 20 minutes over 8 weeks. Cardiorespiratory fitness and hemodynamic response during GXT were also assessed. Cardiovascular biomarkers (endothelin-1 [ET-1], high-sensitivity C-reactive protein [hs-CRP], NT-proBNP, and nitric oxide [NO]) were measured pre- and post-intervention. In the BFRTg, ET-1, hs-CRP, and NT-proBNP levels decreased after BFR training, while maximal systolic blood pressure decreased and VO2max increased (all p < .05). Hemodynamic load also improved, as indicated by reductions in resting and maximal rate-pressure product (RPP) and pulse pressure during maximal exercise (all p < .05). BFR training improved the exercise blood pressure response and cardiorespiratory fitness in runners with EIH. The reduction in hemodynamic load, reflected by decreases in RPP and PP, was accompanied by significant reductions in ET-1, hs-CRP, and NT-proBNP.
To test whether a pneumatic cold-compression system (CC) improves recovery of maximal voluntary contraction (MVC) at 48 h (T4) versus Sham after a standardized hamstring fatigue protocol. Secondary aims were to compare muscle stiffness, microvascular perfusion, pressure pain threshold (PPT), blood lactate, perceived recovery (TQR), and harms across subgroups. This multicenter, randomized, participant- and assessor-blinded, sham-controlled, two-period crossover trial enrolled 80 participants. After fatigue testing, participants received CC (3 °C, 75 mmHg, 10 min twice daily for 3 days) or Sham (15 °C, 15 mmHg). Outcomes were assessed at baseline (T0), post-fatigue (T1), immediately post-first intervention (T2), 24 h (T3), and 48 h (T4). Continuous outcomes were analyzed using mixed-way ANOVA with Population as the between-subject factor and Condition and Time as within-subject factors, followed by Bonferroni-adjusted pairwise comparisons. Paired Cohen’s dz was reported for key within-participant contrasts. TQR was analyzed using rank-based factorial ANOVA, and Borg CR10 scores using ordinal logistic regression. Across populations, MVC was higher under CC than Sham from T2 to T4, with the largest between-condition difference at T4 (all p < .001). Muscle stiffness was lower under CC from T2 to T4 (all p < .001). Microvascular perfusion and pressure pain threshold were higher under CC at T2 - T4 overall (all p < .001), with earlier between-condition differences in MMA athletes and young adults and delayed differences in older adults. Blood lactate was lower under CC only immediately after the first intervention session (T2; p < .001). TQR was higher under CC at T2 - T4 in MMA athletes, at T2 - T3 in older adults, and at T3 only in young adults. No adverse events were reported. CC accelerated recovery after hamstring fatigue, improving strength, stiffness, perfusion, pain thresholds, lactate, and perceived recovery across populations, with earlier benefits in athletes and young adults and delayed but comparable improvements in older adults. Registration: ISRCTN49499065.
Strength training plays an essential role in improving performance and lowering injury incidence among adolescent athletes. However, current training practices often involve premature specialization, insufficient load management, and adult-oriented programming. The periodized National Academy of Sports Medicine's Optimum Performance Training (NASM-OPT) model develops stability, strength, and lower-limb power in a progressive manner, but its long-term effects in adolescents remain unclear. This randomized controlled trial compared NASM-OPT with traditional periodized training to examine the effects on maximal lower-limb strength and explosive power among 42 adolescent athletes randomly allocated to the OPT and CON groups (n = 21 per group). A 26-week intervention was completed in both groups. Squat one-repetition maximum (1RM), countermovement jump (CMJ), squat jump (SJ), pre-stretch augmentation percentage (PSAP), and eccentric utilization ratio (EUR) were assessed at baseline and post-intervention. Repeated-measures ANOVA was used to analyze group×time interactions (α = 0.05). Compared with the CON group, the OPT group demonstrated greater post-intervention values in 1RM (133.1 ± 21.4 vs 119.2 ± 18.0 kg), CMJ (47.4 ± 5.8 vs 39.8 ± 4.0 cm), PSAP (10.63% vs 6.07%), and EUR (1.11 vs 1.06) post-intervention (p < 0.05). The OPT group maintained these improvements throughout the intervention, whereas the CON group showed plateaued values, potentially suggesting enhanced stretch-shortening cycle(SSC) function. Periodized NASM-OPT training efficiently promotes lower-limb strength, explosive power, and SSC function in adolescent athletes. These findings indicate that systematic and progressive programming can optimize performance while minimizing injury risk.
This randomized controlled trial examined whether repeated-sprint training (RST) performed on sand or grass induces different adaptations in collegiate soccer players. Forty-two male players were randomly assigned to a sand-RST group (SAND, n = 14), a grass-RST group (GRASS, n = 14), or a control group (CON, n = 14). SAND and GRASS performed repeated-sprint training during two scheduled training sessions per week for six weeks, whereas CON completed standard technical soccer training of equivalent duration during the same two weekly sessions. All groups continued the same regular team training program, with the intervention delivered within two scheduled weekly sessions. Before and after the intervention, participants completed vertical jump tests including squat jump and countermovement jump, a running based anaerobic sprint test with peak, mean, and minimum power and fatigue index, and a graded treadmill test providing VO2max, anaerobic threshold, and running economy. Baseline-adjusted analyses were conducted to examine between-group differences (ANCOVA for outcomes meeting model assumptions; mixed-design ANOVA when assumptions were violated). These analyses showed significant Group by Time interactions for all jump and running based sprint variables and for VO2max and anaerobic threshold (p < 0.01), whereas the interaction for running economy was not significant (p = 0.15). Compared with GRASS, SAND showed greater improvements in squat jump (p < 0.01), mean power (p = 0.03), minimum power (p < 0.01), and fatigue index (p < 0.01). Aerobic adaptations were comparable between sand and grass, and no clear surface specific advantage was observed for running economy. In conclusion, implementing RST within scheduled team sessions improved jump performance, repeated-sprint performance indices, and aerobic fitness in collegiate soccer players, while sand-based training may provide greater benefits for squat jump and selected outcomes related to repeated-sprint fatigue resistance.
Complex training combines high-load resistance exercises with plyometric actions and can be implemented using different exercise sequences. Given that neuromuscular adaptations are specific to the force-velocity characteristics and fatigue conditions under which training stimuli are applied, exercise order may influence the expression of training adaptations. This study compared the effects of ascending (ACT; plyometrics before resistance exercises) and descending (DCT; resistance before plyometrics) complex training methods on athletic performance in national-level male basketball players. Twenty athletes (ACT: n=8; DCT: n=12) completed an 8-week training program performed twice weekly during the off-season. Both protocols included matched training volumes (sets × repetitions × load) and intensities but differed in exercise sequencing: DCT prioritized resistance exercises before plyometrics, while ACT followed the opposite order. Primary outcomes were change of direction (5-10-5, CODAT) and countermovement jumps without and with arm swing (CMJ, CMJ-A; respectively), squat jumps (SJ). Secondary outcomes included drop jumps from 40 and 60 cm (DJ-40, DJ-60), linear sprint times (5 m, 10 m), and force output during isometric mid-thigh pull (IMTP). After adjustment for baseline performance, no consistent between-group differences were observed for jumping performance during CMJ, CMJ-A, SJ, or DJ, nor for sprinting or change-of-direction performance (all p ≥ 0.05). A significant between-group effect favoring DCT was observed only for CMJ-A peak velocity (p = 0.015) and early-phase isometric force production at 100 ms during the IMTP (p = 0.011). These findings indicate that both ACT and DCT can be effectively implemented during the off-season in national-level basketball players. Exercise sequencing appears to act as a fine-tuning variable that may influence specific neuromuscular qualities, rather than producing broad performance advantages across athletic tasks.
Talent identification (TID) in team sports is complex, influenced by biological, technical, psychological, and socio-cultural factors. Machine learning (ML) offers tools to integrate high-dimensional data, yet its applications in youth TID remain underexplored. Objectives: To systematically review ML approaches applied to youth talent identification in team sports, with emphasis on data domains, algorithms, validation strategies, and interpretability. Eligible studies included peer-reviewed quantitative research applying ML to youth athletes (≤21 years) in team sports for TID outcomes. Searches were conducted in PubMed, Scopus, and Web of Science, supplemented by reference and citation screening. Extracted data items included input data domains (anthropometric, physical, technical, perceptual-cognitive, psychological, socio-cultural, and multi-domain), ML approach, validation methods, performance metrics (e.g., accuracy, AUC, F1-score), and interpretability techniques. Risk-of-bias assessment was implemented using PROBAST. From 228 records, 27 studies met inclusion criteria. Soccer was most studied (n = 13), with others covering rugby, basketball, cricket, volleyball, and Australian football. Sample sizes ranged from 21 to 13,876 athletes, predominantly male. Supervised algorithms (Random Forest, gradient boosting, neural networks, penalized regression) were most common; some studies used unsupervised clustering. Validation practices varied, with few employing nested cross-validation or external testing. Reported discrimination metrics ranged from modest to excellent (ROC-AUC ≈ 0.58-0.96, depending on model and context), yet calibration performance (e.g., Brier score, calibration slope) was rarely reported, and external validation was uncommon. Across studies, predictive accuracy was moderate to high internally but rarely externally confirmed. Risk of bias was high in 59 % of studies, mainly due to inadequate analysis and limited generalizability. Overall, ML shows potential to complement, not replace, traditional TID approaches - acting as a decision-support and hypothesis-generation tool that can assist practitioners in early screening, individualized progression modeling, and evidence-based talent forecasting. To strengthen translational impact, future research should emphasize transparent reporting, calibration assessment, and external validation to ensure robust, applicable ML models for sport talent systems.
