Effects of eccentric resistance training on lower-limb passive joint range of motion: A systematic review and meta-analysis
Medicine and Science in Sports and Exercise
Centre for Human Performance / School of Medical and Health Sciences
Introduction: Substantial increases in joint range of motion (ROM) have been reported after eccentric resistance training; however, between-study variability and sample size issues complicate the interpretation of the magnitude of effect. Methods: 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 standardized difference (Hedge's g) with 95 % confidence intervals. Results: Meta-analysis of 22 ROM outcomes (17 studies, 376 participants) revealed a large increase in lower-limb passive joint ROM (g = 0.86 (95 % confidence intervals, 0.65-1.08)). Subgroup analyses revealed a moderate increase after 4-5 wk (g = 0.63 (0.27-0.98)), large increase after 6-8 wk (g = 0.98 (0.73-1.24)), and moderate increase after 9-14 wk (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. Conclusions: 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 <50% training sessions being performed is suggestive of a more effective exercise mode, although further research is needed to determine the influence of contraction intensity and to confirm the efficacy of eccentric training in clinical populations.