Effects of unilateral and bilateral training on performance in team sports athletes: a systematic review and meta-analysis.

Team sports athletes rely heavily on unilateral movements, yet the comparative performance benefits of unilateral training (UT) versus bilateral training (BT) remain controversial. This meta-analysis systematically examined the effects of UT and BT on strength, jumping, sprinting, and agility in team sports, while considering sport type and training program as potential moderators. A systematic search of PubMed, Web of Science, Cochrane Library, and CNKI databases was conducted to identify controlled trials meeting the PICOS criteria. Primary outcomes were strength, jumping (countermovement jump [CMJ], horizontal jump [HJ], reactive strength index [RSI]), sprinting, and agility. Pooled effects were calculated using standardized mean difference (Hedges' g) through a three-level meta-analysis model, with subgroup and moderator analyses conducted. Fifteen studies involving 355 team sports athletes (basketball, soccer, rugby, and ice hockey) were included. The meta-analysis showed no significant differences between UT and BT in overall strength, jumping, sprinting, and agility. However, UT significantly outperformed BT in unilateral strength (g = 0.68, p = 0.007), unilateral CMJ (g = 0.37, p = 0.025), and unilateral HJ (g = 0.45, p = 0.03). No significant differences were found in bilateral strength, bilateral jumping, and RSI. Subgroup analysis revealed no overall differences across sports, but in basketball, UT had significant advantages over BT in sprinting (g = -0.37, p = 0.04) and agility (g = -0.77, p = 0.04). Regarding training types, UT using plyometric training outperformed BT in strength (g = 0.54, p = 0.03) and sprinting (g = -0.30, p = 0.03), while UT with compound training had significant advantages in agility (g = -0.74, p = 0.04). UT outperforms BT in improving unilateral strength and jumping ability, while producing comparable effects in bilateral performance, sprinting, and agility. These findings underscore the value of UT in team sports involving unilateral movements. Future research should explore its long-term effects, recovery from injury, and neuromuscular adaptations to better optimize training.