Effects of low-intensity endurance and resistance training on mobility in chronic stroke survivors. A pilot, randomized, controlled study

BACKGROUND: Chronic stroke survivors are exposed to long-term disability and physical deconditioning, effects that may impact their independence and quality of life. Community-based programs optimizing the dose of exercise therapy that are simultaneously low risk and able to achieve high adherence should be identified. AIM: We tested the hypothesis that an 8-week, community-based, progressive mixed endurance- resistance exercise program at lower cardiovascular and muscular load yielded more mobility benefits than a higher-intensity program in chronic stroke survivors. DESIGN: A two-arm, parallel-group, pilot randomized, controlled clinical trial. SETTING: Hospital (recruitment); community-based adapted physical activity center (training). POPULATION: Thirty-five chronic stroke patients (mean age: 68.4±10.4 years; 27 males). METHODS: Participants were randomized to a Low-intensity Experimental (LI-E; n=18) or a High-intensity Active Control group (HI-C; n=17). Patients in the LI-E group performed over- ground intermittent walking (weeks 1-8) and muscle power training with portable tools (weeks 5-8); patients in the HI-C group executed treadmill walking (weeks 1-8) and strength training with gym machines (weeks 5-8). Changes in mobility, assessed using the 6-Minute Walking Distance (6MWD), were the primary outcome. Secondary outcomes included quality of life (Short Form-36 questionnaire; SF-36), gait speed (10-meter walking test), balance (Berg Balance Scale) and muscle performance of the lower limbs (strength and power of the quadriceps and femoral biceps). RESULTS: After 8 weeks, the 6MWD revealed more improvement for the LI-E group than the HI- C group (P=0.009). The SF36 physical activity domain (P=0.012) and peak power of the femoral quadriceps and biceps were also significantly improved for the LI-E group (P=0.008 and P<0.001, respectively) compared with the HI-C. Gait speed, balance and lower-limb strength increased in both groups; no significant differences were noted. The muscle power of the affected limb was the muscle parameter most correlated with mobility in the entire population. CONCLUSION: A low-intensity exercise program exhibited better results in terms of mobility, quality of life and muscle power compared with a higher-intensity program. Data need to be confirmed in a larger trial. CLINICAL REHABILITATION IMPACT: The effectiveness, low-intensity and possible implementation in poorly equipped community-based settings make the LI-E program potentially suitable for stroke survivors and frail individuals.