Effects of Eccentric Resistance Training on Lower-Limb Passive Joint Range of Motion: A Systematic Review and Meta-analysis

Abstract

ABSTRACTIntroductionSubstantial 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.MethodsPubMed, 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’sg) with 95% confidence intervals.ResultsMeta-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.ConclusionsThese 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.