Effects of Bilateral and Unilateral Resistance Training on Horizontally Orientated Movement Performance: A Systematic Review and Meta-analysis.


Moran J(1), Ramirez-Campillo R(2), Liew B(3), Chaabene H(4)(5), Behm DG(6), García-Hermoso A(7)(8), Izquierdo M(7)(9), Granacher U(4).
Author information:
(1)School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, UK. [Email]
(2)Department of Physical Activity Sciences, Universidad de Los Lagos, Osorno, Chile.
(3)School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, UK.
(4)Division of Training and Movement Science, University of Potsdam, Potsdam, Germany.
(5)High Institute of Sports and Physical Education, Kef, University of Jendouba, Jendouba, Tunisia.
(6)School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Canada.
(7)Navarrabiomed, Complejo Hospitalario de Navarra
(CHN)-Universidad Pública de Navarra
(UPNA), IdiSNA, Pamplona, Spain.
(8)Laboratorio de Ciencias de la Actividad Física, el Deporte y la Salud, Universidad de Santiago de Chile, USACH, Santiago, Chile.
(9)Grupo GICAEDS. Programa de Cultura, Física, Deporte y Recreación, Universidad Santo Tomás, Bogotá, Colombia.


BACKGROUND: Both bilateral (BLE) and unilateral resistance exercise (ULE) methods can confer benefit to an athlete, but it remains to be established which has a greater effect on movement speed. OBJECTIVES: To evaluate the effects of BLE and ULE on horizontal movement performance. DATA SOURCES: Google Scholar, CrossRef, and PubMed. STUDY ELIGIBILITY CRITERIA: To qualify for inclusion in the meta-analysis, studies must have included a resistance training intervention that compared the effects of BLE and ULE on a measure of movement speed such as sprinting in healthy study participants. STUDY APPRAISAL AND SYNTHESIS METHODS: We used the inverse-variance random-effects model for meta-analyses. Effect sizes (standardised mean difference), calculated from measures of horizontally orientated performance, were represented by the standardised mean difference and presented alongside 95% confidence intervals (CI). RESULTS: Though both modalities were effective (BLE = 0.60 [95% CI 0.34, 0.87], Z = 4.44 [p < 0.01]; ULE = 0.57 [95% CI 0.24, 0.89], Z = 3.44 [p = 0.0006]), there was no difference between the effect of BLE and ULE on movement speed (0.17 [95% CI - 0.15, 0.50], Z = 1.03 [p = 0.30]). For BLE, combined strength and plyometric training had the largest effect size (0.88 [95% CI 0.40, 1.36]]) followed by plyometric training (0.55 [95% CI 0.09, 1.01]), with the lowest effect in strength training (0.42 [95% CI - 0.02, 0.86]). For ULE, the largest effect size for training type was in plyometric training (0.78 [95% CI 0.33, 1.24]) closely followed by combined (0.63 [95% CI 0.03, 1.24]) with strength (0.29 [95% CI - 0.42, 1.01]) having a substantially lower effect size. CONCLUSIONS: Both BLE and ULE are effective in enhancing horizontal movement performance. However, contrary to popular opinion, supported by the concept of training specificity, ULE was no more effective at achieving this than BLE.