This review provides evidence that PRT is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported.
A randomized, controlled trial of quadriceps resistance exercise and vitamin D in frail older people: the Frailty Interventions Trial in Elderly Subjects (FITNESS).
To determine the effectiveness of vitamin D and home-based quadriceps resistance exercise on reducing falls and improving the physical health of frail older people after hospital discharge.
                Multicenter, randomized, controlled trial with a factorial design.
                Five hospitals in Auckland, New Zealand, and Sydney, Australia.
                Two hundred forty-three frail older people.
                Patients were randomized to receive a single dose of vitamin D (calciferol, 300,000 IU) or placebo tablets and 10 weeks of high-intensity home-based quadriceps resistance exercise or frequency-matched visits.
                The primary endpoints were physical health according to the short-form health survey at 3 months and falls over 6 months. Physical performance and self-rated function were secondary endpoints. Assessments took place in the participants' homes at 3 and 6 months after randomization and were performed by blinded assessors.
                There was no effect of either intervention on physical health or falls, but patients in the exercise group were at increased risk of musculoskeletal injury (risk ratio = 3.6, 95% confidence interval = 1.5-8.0). Vitamin D supplementation did not improve physical performance, even in those who were vitamin D deficient (<12 ng/mL) at baseline.
                Neither vitamin D supplementation nor a home-based program of high-intensity quadriceps resistance exercise improved rehabilitation outcomes in frail older people after hospitalization. There was no effect of vitamin D on physical performance, and the exercises increased the risk of musculoskeletal injury. These findings do not support the routine use of these interventions at these dosages in the rehabilitation of frail older people.