Single limb exercise: pilot study of physiological and functional responses to forced use of the hemiparetic lower extremity.

PURPOSE: Stroke-related deficits can impede both functional performance and walking tolerance. Individuals with hemiparesis rely on the stronger limb during exercise and functional tasks. The single limb exercise (SLE) intervention was a unique training protocol that focused only on the hemiparetic limb. Our objective was to determine the effect of the SLE intervention on cardiorespiratory fitness parameters. METHODS: Twelve participants (5 male) with a mean age of 60.6 +/- 14.5 years and 69.1 +/- 82.2 months post stroke participated in the training intervention. All participants performed SLE using the hemiparetic leg three times a week for 4 weeks. The nonhemiparetic limb served as the control limb and did not engage in SLE. Peak oxygen uptake (VO2 peak) and oxygen uptake (VO2) were measured at baseline and post intervention in all 12 participants. At pre and post intervention, gait velocity was assessed in a subset of participants (n = 7) using the 10-m fast-walk test. RESULTS: After the 4-week SLE training intervention, significant improvements were found for VO2 during submaximal work effort (P = .009) and gait velocity (n = 7) (P = .001). Peak oxygen uptake did not increase (P = .41) after the training intervention. CONCLUSION: These data suggest that SLE training was an effective method for improving oxygen uptake and reducing energy expenditure during submaximal effort. Unilateral exercise focused on the hemiparetic leg may be an effective intervention strategy to consider for stroke rehabilitation.

Single limb exercise induces femoral artery remodeling and improves blood flow in the hemiparetic leg poststroke.

BACKGROUND AND PURPOSE: After stroke, individuals have decreased mobility of the hemiparetic leg, which demands less muscle oxygen consumption; thus, blood flow decreases. The purpose of this study was to determine the effect of single limb exercise (SLE) on femoral artery blood flow, diameter, and peak flow velocity in the hemiparetic leg after stroke. METHODS: Twelve individuals (60.6+/-14.5 years of age; 5 male) with chronic stroke (69.1+/-82.2 months; 5 with right-sided hemiparesis) participated in the study. The intervention consisted of a SLE knee extension/flexion protocol 3 times per week for 4 weeks. Using Doppler ultrasound, bilateral femoral artery blood flow, diameter, and peak flow velocity were assessed at baseline, after 2 weeks, and after 4 weeks of SLE. RESULTS: Using repeated-measures analysis of variance, femoral artery blood flow, arterial diameter, and blood flow velocity in the hemiparetic limb were significantly improved (P<0.0001) after the SLE. No significant changes occurred in the nontrained limb for any outcome measures. CONCLUSIONS: These data suggest that a 4-week SLE training program that increases muscular activity in the hemiparetic limb improves femoral artery blood flow, diameter, and peak velocity. SLE may be an important training strategy in stroke rehabilitation to minimize the vascular changes that occur poststroke due to decreased activity of the hemiparetic limb.