Abstract
Background: In randomized controlled trials, power training has been shown to be more effective than conventional resistance training for improving physical function in older adults; however, most of these trials used pneumatic machines for power training. Considering that the majority of the people only have access to plate-loaded machines, it is important to examine the benefits and adverse effects of power training using plate-loaded machines compared to pneumatic machines to determine the feasibility of their use. Objective: The purpose of this investigation was to compare high-velocity training using pneumatic machines and standard plate-loaded machines on power, physical function, strength and adverse effects. Methods: A total of 36 independently-living older adults, 65 years or older, were randomized into two groups: pneumatic machine (Pn, n=19) and plate-loaded machine (PL, n=17). After 12 weeks of high-velocity training twice per week, groups were compared using an intention-to-treat approach. The primary outcome was lower body power measured using a linear transducer and upper body power using medicine ball throw. Secondary outcomes were lower and upper body strength, the Physical Performance Battery (PPB), gallon jug test and get up and go test, and self-reported function using Patient Reported Outcomes Measurement Information System (PROMIS) and an online video questionnaire. The outcome assessor was blinded to group membership. Results: Lower body power significantly improved in both groups (Pn: 19%, PL: 31%), but there was no significant difference between the groups (d=0.4, 95% CI (-1.1, 0.3). Upper body power significantly improved only in the PL group, but showed no significant difference between the groups (Pn: 3%, PL: 6%). For secondary outcome of balance, the Pn group showed a significant difference between the groups and favored the Pn group (d=0.7, 95% CI (0.1, 1.4). There were no statistically significant differences between the groups for PPB, gallon jug transfer, strength, get up and go or self-reported function. No intervention-related or serious adverse events were reported in either of the groups. Conclusions: Pneumatic machines were not superior to plate-loaded machines in improving power in older adults. Pneumatic and plate-loaded machines were both effective in improving lower body power and physical function in older adults. The results suggest that power training can be effectively and safely performed using plate-loaded machines among older adults.