Effects of unilateral vs. bilateral resistance training interventions on measures of strength, jump, linear and change of direction speed: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of comparative resistance training interventions
PubMed 35959319 · doi:10.5114/biolsport.2022.107024
What was done
Authors searched Web of Science, PubMed, Google Scholar, and ResearchGate for studies comparing unilateral and bilateral resistance training interventions on athletic performance. Fourteen studies comprising 392 participants aged 16 to 26 years met inclusion criteria and were included in the quantitative meta-analysis. Evaluated outcomes included unilateral and bilateral strength, unilateral and bilateral jumping, change of direction speed, and linear speed.
What was found
Unilateral training produced a large advantage over bilateral training for unilateral jump performance (ES = 0.89 [95% CI: 0.52, 1.26]). Bilateral training produced a small advantage over unilateral training for bilateral strength (ES = -0.43 [-0.71, -0.14]). Non-significant differences were observed for unilateral strength (ES = 0.26 [-0.03, 0.55]), bilateral jump performance (ES = -0.04 [-0.31, 0.23]), change of direction (ES = 0.31 [-0.01, 0.63]), and linear speed (ES = -0.12 [-0.46, 0.21]).
Why it matters
The findings demonstrate task specificity for jumping and bilateral strength, while showing that unilateral and bilateral training provide similar transfer to sprinting, change of direction, and unilateral strength.
Limits
The overall sample size was modest (392 subjects across 14 studies), participants were restricted to ages 16 to 26 years, and overall study quality was rated as moderate. Specific exercise selections, intensities, and training volumes varied across the included trials.