The effects of eccentric versus traditional resistance training on muscle strength, power, hypertrophy, and functional performance in older adults: A systematic review with multilevel meta-analysis of randomized controlled trials

This systematic review and meta-analysis aimed to examine the effects of eccentric resistance training (ERT) versus traditional resistance training (TRT) on muscle strength, power, hypertrophy, and functional capacity in healthy older adults. Eleven randomized-controlled-trials were included. Between-group analysis for strength demonstrated a small but significant effect in favour of ERT over TRT (standardized-mean-difference [SMD]=0.27). No significant differences were found for functional capacity (SMD=0.12), muscle power (SMD=0.20), or hypertrophy (SMD=-0.03). Within-group analyses for ERT indicated large, significant effects for strength (SMD=0.96) and functional capacity (SMD=1.09) with no significant effects for power and hypertrophy. For TRT, large and moderate significant effects were found for functional capacity (SMD=0.94) and strength (SMD=0.59), respectively, with no significant effects for power and hypertrophy. Meta-regression analysis indicated that longer intervention durations were approaching-significance in their association with greater muscle strength gains with ERT than TRT (p = 0.09). With ERT, increasing age was significantly associated with greater muscle power gains (p = 0.04) and more sessions were approaching-significance in their association with hypertrophy (p = 0.08). Regarding TRT, a higher proportion of female participants was approaching-significance in its association with greater functional capacity gains (p = 0.09). In summary, ERT yields slightly greater muscle strength gains than TRT in older adults, while both produced comparable effects on functional capacity, muscle power, and hypertrophy. The two training modalities elicit moderate-to-large within-group improvements in strength and functional capacity but not in power or hypertrophy. ERT outcomes appear to be moderated by training duration, session number, and age, whereas TRT effects relate to female proportion. Overall, both modalities are effective for older adults, with a slight strength advantage for ERT.