Increased Velocity Exercise Specific to Task Training Versus the National Institute on Aging's Strength Training Program: Changes in Limb Power and Mobility

Abstract

This study was designed to evaluate the benefits of InVEST (Increased Velocity Specific to Task) training on limb power and mobility among mobility-limited older adults. We conducted a single blinded, randomized controlled trial among 138 mobility-limited community-dwelling older adults, evaluating two 16-week supervised exercise programs. The intervention group participated in InVEST training, and the control group participated in the National Institute on Aging's (NIA) strength training program. Primary outcomes were changes in limb power per kilogram and mobility performance as measured by the Short Physical Performance Battery (SPPB). After 16 weeks, InVEST produced significantly greater improvements in limb power than NIA (p = .02). There was no significant difference in strength improvements. Both groups had significant changes in SPPB of greater than 1 unit. Self-reported function was also significantly improved in both groups. Differences between groups were not statistically different. In a post hoc analysis when participants were categorized by the manifestation of baseline leg velocity impairments (N = 68), InVEST training produced effect size differences in SPPB that were clinically meaningful (SPPB Group × Time difference 0.73 units, p = .05). Among mobility-limited older adults, both NIA and InVEST produce robust changes in observed physical performance and self-reported function. These improvements were not meaningfully different by statistical or clinical criteria. Compared with NIA, InVEST training produced greater improvements in limb power and equivalent improvements in strength. Observed differences between NIA and InVEST based upon baseline leg impairment status are informative for futures studies.