Power Training In Older Adults

Abstract

Peak muscle power (the product of muscle force and speed of movement) declines earlier and at a faster rate than muscle strength with advancing age. Muscle power is a strong predictor of functional performance and is also associated with impairment in activities of daily living. PURPOSE To examine the feasibility of a 12-wk lower extremity power training intervention in older adults with mild to moderate self-reported disability. We hypothesized that power training (PT) will lead to similar improvements in lower extremity muscle strength and will yield greater improvements in lower extremity muscle power compared to traditional progressive resistance training (PRT). METHODS Older adults (N = 45) with mild to moderate self-reported disability (11 male, 34 female, mean ± SD age: 74.8 ± 5.7 yrs, BMI: 30.2±5.8 kg/m2, MMSE: 28.9 ± 1.2, CES-D. 10.3 ± 6.8) were randomized to 3 groups (PT, PRT, control). 1RM (Newtons) and peak power (Watts) for knee extension (KE) and leg press (LP) were measured at baseline, 6 wks, and 12 wks. 3 sets (8–10 reps) of PT (concentric phase performed “as fast as possible”) or PRT (concentric phase performed to a 3 count) were completed 3X/wk for 12 wks on pneumatic KE and LP machines at ∼70% of the 1RM with a warm-up and cool-down and flexibility exercises. Mixed-effects models with unstructured covariances between repeated observations were used. Multiple comparisons were performed using Fisher's protected LSD procedure. RESULTS Compliance was 70% overall, and 85% for those completing the intervention. Six participants dropped out for health reasons unrelated to the intervention. There were no serious adverse events related to the training. There were no significant visit* group interactions in any analyses (p >.05). For all analyses, there was a significant main effect for group (p <.05) but not for visit (p > .05) indicating that changes in strength and power occurred in the first 6 wks of the intervention. KE and LP 1RM improved similarly in PT and PRT groups (∼30% increase in both groups, p >.05) and both groups improved compared to the control group (∼8% increase in control, p <.05). Maximum KE and LP power was significantly greater in the PT group (68, 84% increase, respectively) compared to PRT (27, 34% increase, respectively) and control groups (1.5, 18.6% increase, respectively, p <.05). The difference between the maximum KE and LP power for the PRT and control groups was not significant. CONCLUSIONS PT appeared to be a feasible mode of training in older adults. PT improved KE and LP 1RM strength similarly and was more effective in improving peak KE and LP power than RPT in older adults.