Effects of eccentric resistance training on lower-limb passive joint range of motion: A systematic review and meta-analysis

Substantial increases in joint range of motion (ROM) have been reported following eccentric resistance training, however between-study variability and sample size issues complicate the interpretation of the magnitude of effect. PubMed, Medline and SPORTDiscus databases were searched for studies examining the effects of eccentric training on lower-limb passive joint ROM in healthy human participants. Meta-analysis used an inverse-variance random-effects model to calculate the pooled standardised difference (Hedge's g) with 95% confidence intervals (CI). Meta-analysis of 22 ROM outcomes (17 studies; 376 participants) revealed a large increase in lower-limb passive joint ROM (g = 0.86 [CI = 0.65, 1.08]). Subgroup analyses revealed a moderate increase after 4-5 weeks (g = 0.63 [0.27, 0.98]), large increase after 6-8 weeks (g = 0.98 [0.73,1.24]), and moderate increase after 9-14 weeks (g = 0.75 [0.03, 1.46]) of training. Large increases were found in dorsiflexion (g = 1.12 [0.78, 1.47]) and knee extension (g = 0.82 [0.48, 1.17]), but a small increase in knee flexion was observed (g = 0.41 [0.05, 0.77]). A large increase was found after isokinetic (g = 1.07 [0.59, 1.54]) and moderate increase after isotonic (g = 0.77 [0.56, 0.99] training. These findings demonstrate the potential of eccentric training as an effective flexibility training intervention and provide evidence for 'best practice' guidelines. The larger effect after isokinetic training despite