Effects of standalone plyometric training on countermovement jump and linear sprint performance in volleyball athletes: a systematic review and meta-analysis

Introduction Volleyball is a dynamic, intermittent court sport characterized by repeated high-force vertical jumps and rapid linear sprints, both of which rely heavily on lower-body explosive power and efficient stretch-shortening cycle function. Previous investigations examining plyometric training in volleyball populations have frequently integrated this modality alongside concurrent strength, technical or agility training, making it difficult to isolate the specific effects of plyometric training alone on core physical performance metrics. Accordingly, the present systematic review and meta-analysis was conducted to quantify the independent effects of standalone plyometric training on countermovement jump (CMJ) height and linear sprint performance in volleyball athletes, and to identify potential moderating variables that influence adaptive responses. Methods A systematic literature search was performed across five electronic databases (PubMed, Web of Science, Embase, Cochrane Library, and SPORTDiscus), with the search closing date set to July 10, 2026. The search was restricted to peer-reviewed journal articles published in English or Chinese; grey literature sources were not included. Controlled trials comparing standalone plyometric training to a passive or usual-training control group in volleyball athletes of any age or competitive level were eligible for inclusion. Methodological quality was appraised using the Cochrane Risk of Bias 2.0 (RoB 2) tool for randomized controlled trials (RCTs) and the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool for quasi-experimental trials. Pooled effect sizes were expressed as Hedges’ g with corresponding 95% confidence intervals (CIs), calculated under a random-effects model with restricted maximum likelihood estimation and Hartung-Knapp adjustment. Standard meta-analytic procedures were applied to assess between-study heterogeneity, publication bias, and subgroup effects stratified by age, sex, and total intervention duration. Between-subgroup interaction tests were conducted to evaluate potential moderating effects. Results Overall, 12 controlled trials encompassing a total of 326 volleyball athletes met all inclusion criteria and were retained for quantitative synthesis. Pooled analysis indicated that standalone plyometric training produced statistically significant improvements in both countermovement jump performance (g = 0.55, 95% CI 0.36 to 0.75; I 2 = 0.0%) and linear sprint capacity (g = −0.48, 95% CI −0.90 to −0.07; I 2 = 21.2%). Subgroup analyses showed no statistically significant between-group differences for CMJ performance by age (Q_between = 3.11, p = 0.077), intervention duration (Q_between = 0.08, p = 0.771), or sex (Q_between = 0.38, p = 0.538). For sprint outcomes, a significant overall beneficial effect was observed at the pooled population level, and sprint distance was identified as a statistically significant moderator (Q_between = 6.09, p = 0.014), with larger effects observed for distances of 20 m and longer. No significant publication bias was detected, though statistical power was limited by the small number of included studies. Conclusion Standalone plyometric training is associated with measurable improvements in both vertical jump and linear sprint performance in volleyball athletes. No statistically significant age-related differences were detected for vertical jump improvements, with both age groups showing significant beneficial effects, while significant sprint improvements are observed at the overall population level with no statistically significant differential effect across age groups. Future well-designed, standardized trials are warranted to establish volleyball-specific plyometric protocols and optimize evidence-based conditioning practices for this athletic population. Systematic Review Registration https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420261454012 , identifier CRD420261454012.