Effects of Unilateral Versus Bilateral Training on Physical Performance Outcomes in Team Sport Athletes: A Systematic Review and Meta-Analysis

Abstract

Objective: This systematic review and meta-analysis evaluated the comparative effects of unilateral versus bilateral training on physical performance outcomes relevant to team sport athletes. The review addresses strength, power, speed, agility, reactive strength, and core stability rather than direct match performance or sport-specific skill execution. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, nine electronic databases were searched from inception through 10 August 2025, for randomized controlled trials directly comparing unilateral and bilateral training. Methodological quality was assessed using the Cochrane Risk of Bias 2.0 tool, and certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. Results: Twenty studies involving 539 unique participants were included. Compared with bilateral training, unilateral training showed potential advantages for agility (standardized mean difference [SMD] = −0.73), sprint performance (SMD = −0.30), and muscular strength (SMD = 0.29). However, effect magnitude and certainty varied across outcomes, and several analyses showed substantial heterogeneity or limited certainty. The primary vertical-jump estimate favored unilateral training (SMD = 0.38), but the association was no longer statistically significant after trim-and-fill adjustment. Moderator analyses were exploratory and should not be interpreted as confirming optimal training parameters. In the one-effect-per-sample sensitivity analysis, the vertical-jump and muscular-strength estimates were no longer statistically significant, whereas excluding the two acute crossover studies did not change any affected outcome conclusion. Conclusions: Unilateral training may be used as a complementary strategy for selected physical performance qualities relevant to team sport participation, particularly agility and sprint performance. These findings remain preliminary because of heterogeneity, potential publication bias, methodological limitations, and moderate-to-very-low GRADE certainty. The evidence does not justify replacing bilateral training or prescribing a specific unilateral program across sports.