Background: As dietary supplements have become integral to meeting athletes’ specialised nutritional requirements, research into their effects on performance has intensified. Yet inconsistent findings leave the efficacy of some supplements—most notably branched-chain amino acids and β-hydroxy-β-methylbutyrate (HMB)—open to debate. To clarify which products offer the greatest benefit, we undertook a systematic review and network meta-analysis aimed at identifying the supplements most effective for athletes, including protein, creatine, β-alanine, HMB, vitamin D, caffeine, and others. Methods: PubMed, Web of Science, the Cochrane Library, Embase and SPORTDiscus were searched from database inception to 15 March 2024 for RCTs evaluating the effects of dietary supplements (including but not limited to protein, creatine, β-alanine, HMB, caffeine, and vitamin D) on athletic performance. Risk of bias was appraised with the revised Cochrane RoB 2 tool. A network meta-analysis was performed in R. Results: We included 35 randomized controlled trials comprising 991 athletes who completed strength and conditioning training in conjunction with various dietary supplements or a placebo. The risk of bias assessment indicated that 8.57% of studies were at low risk, 88.57% had some concerns, and 2.86% were at high risk of bias. Protein supplementation yielded the greatest improvement in muscular strength (standardized mean difference [SMD] = 0.64, 95% confidence interval [CI] 0.31–0.97; surface under the cumulative ranking curve [SUCRA] = 99.6%; very low-certainty evidence). Both β-alanine (SMD = 0.41, 95% CI 0.10–0.72; SUCRA = 89.0%; moderate-certainty evidence) and creatine (SMD = 0.30, 95% CI 0.07–0.53; SUCRA = 76.06%; moderate-certainty evidence) significantly enhanced jump performance, with β-alanine ranking marginally higher. Creatine also reduced sprint time (SMD = −0.42, 95% CI − 0.68 to −0.16; SUCRA = 94.57%; moderate-certainty evidence). No supplement significantly increased lean body mass. Conclusion: Protein supplementation appears to be the most effective strategy for increasing muscular strength; β-alanine and creatine both improve jump performance, with β-alanine offering marginally superior effectiveness; and creatine is particularly beneficial for sprint speed. As none of the supplements meaningfully increased muscle mass, practitioners should align supplementation strategies with the targeted performance attribute and training phase to optimise the synergy between nutrition and training and maximise athletic outcomes. Systematic review registration: PROSPERO , CRD420251048402.

Zhang, M, Chen, L, Dai, J, Yang, Q, Huang, Z, He, J, Ji, H, Sun, J, and Li, D. Application of a new monitoring variable: Effects of power loss during squat training on strength gains and sports performance. J Strength Cond Res 38(4): 656–670, 2024—This study aimed to compare the effects of power loss (PL) autoregulated volume (PL10 and PL20) with standardized fixed-load (FL) prescription on strength, sports performance, and lean body mass (LBM). Thirty-five female basketball players from a sports college were randomly assigned to 3 experimental groups (PL10, n = 12; PL20, n = 12; and FL, n = 11, respectively) that performed a resistance training (RT) program with wave-like periodization for 10 weeks using the back squat exercise. Assessments performed before (Pre) and after (Post) intervention included assessed 1 repetition maximum (1RM), body composition, 20-m sprint (T20M), change of direction (COD), and jump performance, including countermovement jump with arm swing, maximum vertical jump, and reactive strength index. Three groups showed significant improvements in strength (effect size [ES]: PL10 = 2.98, PL20 = 3.14, and FL = 1.90; p < 0.001) and jump performance (ES: PL10 = 0.74, PL20 = 1.50, and FL = 0.50; p <0.05–0.001). However, PL10 and PL20 demonstrated different advantages in sports performance compared with FL (group × time interaction, p <0.05). Specifically, PL10 significantly improved COD performance (ES = −0.79 ∼ −0.53, p <0.01), whereas PL20 showed greater improvements in sprint (ES = −0.57, p <0.05) and jump performance (ES = 0.67–1.64, p <0.01–0.001). Moreover, PL10 resulted in similar gains to PL20 and beneficial improvements compared with FL in LBM, despite performing the least repetitions. Overall, the study indicates that power loss–based autoregulation induces greater gains in LBM and sports performance, as well as eliciting a higher efficiency dose response than standardized FL prescriptions, particularly for PL10. Therefore, incorporating PL monitoring in training programs is recommended, and further studies on power-based RT would be worthwhile.

The purpose of this study was to compare the impact of velocity-based resistance training (VBRT) and percentage-based resistance training (PBRT) on anaerobic ability, sprint performance, and jumping ability. Eighteen female basketball players from a Sport College were randomly divided into two groups: VBRT (n = 10) and PBRT (n = 8). The six-week intervention consisted of two sessions per week of free-weight back squats with linear periodization from 65% to 95%1RM. In PBRT, the weights lifted were fixed based on 1RM percentage, while in VBRT, the weights were adjusted based on individualized velocity profiles. The T-30m sprint time, relative power of countermovement jump (RP-CMJ), and Wingate test were evaluated. The Wingate test assessed peak power (PP), mean power (MP), fatigue index (FI), maximal velocity (Vmax), and total work (TW). Results showed that VBRT produced a very likely improvement in RP-CMJ, Vmax, PP, and FI (Hedges’ g = 0.55, 0.93, 0.68, 0.53, respectively, p < 0.01). On the other hand, PBRT produced a very likely improvement in MP (Hedges’ g = 0.38) and TW (Hedges’ g = 0.45). Although VBRT showed likely favorable effects in RP-CMJ, PP, and Vmax compared to PBRT (p < 0.05 for interaction effect), PBRT produced greater improvements in MP and TW (p < 0.05 for interaction effect). In conclusion, PBRT may be more effective in maintaining high-power velocity endurance, while VBRT has a greater impact on explosive power adaptations.

Background: In volleyball, certain maneuvers (e.g., depth jumps) involve a long stretch-shortening cycle (long-SSC) characterized by a prolonged landing-to-takeoff phase (ground contact time ≥222 ms). However, the key biomechanical factors influencing jump height in such long-SSC movements remain unclear, particularly in female athletes. This study investigated depth jump biomechanics in female volleyball players to identify performance-related factors and inform training optimization.Methods: Eighteen trained female volleyball players performed maximal-effort depth jumps under 3D motion capture. Pearson correlation analysis examined relationships between biomechanical variables and jump height. Participants were then divided into high (HJG) and low (LJG) jump-height groups based on a median split and compared using independent samples t-tests.Results: Jump height correlated positively with peak propulsion velocity, peak propulsion power, knee flexion-extension angle, peak ankle moment, and peak propulsion impulse (all p < 0.05). Compared with LJG, HJG exhibited significantly greater jump height, propulsion velocity, knee flexion-extension angle, and ankle moment but lower leg stiffness and braking force. Differences in contact time, propulsion impulse, and hip angle had moderate effect sizes.Conclusion: Peak propulsion velocity was the strongest correlate of jump height in long-SSC depth jumps. Propulsion-phase variables, particularly ankle torque and impulse, were more influential than braking-phase variables. In contrast to short-SSC tasks, high lower-limb stiffness appears to provide limited benefit for maximizing performance in long-SSC movements. Training for female volleyball players should therefore prioritize developing propulsion-phase power and ankle strength for these types of jumps.Trial registration number: ChiCTR2400094392; Registration date: 22/12/2024.

Correction: Correction: Effects of different dietary supplements combined with conditioning training on muscle strength, jump performance, sprint speed, and muscle mass in athletes: a systematic review and network meta-analysis (This Correction supplements a previous Correction to the article; DOI: 10.3389/fnut.2025.1670394.) Author affiliation In the published article, Affiliation 3 was incorrectly given as "Department of Physical Education, Guangzhou Sport University, Guangzhou, China." The correct affiliation is: "School of Physical Education, Guangzhou Sport University, Guangzhou, China." This is a nomenclature update for the same institutional unit. Only Affiliation 3 is affected (author linked to Affiliation 3: Wen Chen). All other affiliations remain unchanged. The authors apologize for this error and state that it does not affect the scientific conclusions of the article in any way.

Dietary supplements are often used during training to support energy provision, recovery, and adaptation, yet effects on peak and mean anaerobic power, VO ₂ max, and endurance performance remain inconsistent. Unlike prior syntheses centred on neuromuscular outcomes (strength and hypertrophy), this study compared six common supplements—protein, creatine, β‐alanine, HMB, vitamin D, and nitrate—on energy‐system performance (peak anaerobic power, mean anaerobic power, VO ₂ max, and endurance performance) using network meta‐analysis. PubMed, Web of Science, Cochrane Library, Embase, and SPORTDiscus were searched from inception to 15 March 2025 for RCTs examining dietary supplements and athletic performance. Risk of bias was assessed with the revised Cochrane tool. Random‐effects network meta‐analyses were conducted in R 4.3.1 and Stata 18. Thirty RCTs involving 693 athletes undergoing training programmes combined with supplements or placebo met the inclusion criteria. For peak anaerobic power, protein (SMD 0.85; 95% CI 0.27–1.44; SUCRA 82.9%; moderate certainty), creatine (0.62; 0.20–1.03; 62.5%; moderate), HMB (0.60; 0.28–0.94; 60.7%; moderate), and β‐alanine (0.58; 0.09–1.07; 57.4%; very low) were superior to placebo. In mean power, β‐alanine (0.75; 0.20–1.31; 74.1%; very low), protein (0.74; 0.27–1.20; 73.9%; very low), and creatine (0.74; 0.08–1.39; 71.0%; very low) showed consistent benefits, while HMB provided a moderate improvement (0.45; 0.05–0.86; 45.8%; very low). Endurance performance improved only with protein (0.99; 0.16–1.83; 94.3%; very low). No supplement affected VO ₂ max. Protein most effectively enhances peak power and endurance performance; β‐alanine and creatine excel in mean power; creatine and HMB also aid peak power; none improve VO ₂ max. Trial Registration: PROSPERO identifier: CRD420251106522