Effect of progressive resistance training on muscle performance after chronic stroke.

Abstract

This study investigated the effects of high-intensity progressive resistance training (PRT) and high-intensity cycling (cycling) on muscle performance and the time course of strength gains in a chronic stroke population. Forty-eight individuals with chronic stroke sequelae (mean +/- SD; age = 63 +/- 9 yr, time since stroke = 57 +/- 54 months) were randomly allocated to one of four treatment groups: PRT + cycling, PRT + sham cycling, sham PRT + cycling, or sham PRT + sham cycling groups in a fully factorial clinical trial. Thirty exercise sessions were conducted over a 10- to 12-wk period. The main outcomes investigated were measures of unilateral muscle strength, peak power, and muscle endurance. Those undergoing PRT improved their lower limb muscle strength, peak power, and endurance compared with participants receiving sham PRT or cycling only (P < 0.05), and combined exercise was not superior to PRT alone. Strength improvements occurred primarily during the first 6 to 8 wk (98%-100% of total gain) and then reached a plateau during the final 2 to 4 wk. We have shown for the first time in a direct comparison study that high-intensity PRT, but not cycling or sham exercise, can improve muscle strength, peak power, and muscle endurance in both affected and unaffected lower limbs after chronic stroke by a significant and clinically meaningful amount. Although strength gains plateaued earlier than anticipated, adherence to the intended continuous high-intensity progressive overload protocol was largely achieved (average load of 84% +/- 4% of one repetition maximum).