The effect of strengthening exercises on the muscle strength of involved lower extremity and locomotor performance in chronic hemiparesis following stroke

Background: The most common manifestation of disturbed neurological function following stroke is motor weakness. The purpose of this study was to determine strength and 2 locomotor tasks impairments, gait on level surfaces and stair climbing impairments in hemiparetic patients and the effects of concentric strengthening exercises of involved lower-extremity muscles in treatment of these impairments. Methods: In a clinical trial, thirty four hemiparetic patients (12 months post stroke) aging 52.41 ± 6.19 years participated in the study through simple non-probability sampling. Patients were assigned randomly to either an experimental group or a control group. The isometric strength of seven muscle groups was measured with a hand-held dynamometer and gait on level surfaces and stair climbing were measured using DGI (Dynamic Gait Index) before and after 12 sessions of intervention. The experimental group received strengthening exercises in addition to functional and balance exercises. The control group received only functional and balance exercises. Independent and paired t-tests and Mann-Whitney and Wilcoxon tests were used for comparison between the pretreatment and post treatment results. Results: In experimental group total strength of involved lower extremity increased from 30.7 ± 16.3 kg to 57.1 ± 12.9 kg and in control group from 33.4 ± 14.6 kg to 37.9 ± 15.8 kg (P < 0.0001). Mean difference of experimental group (26.6) was higher than control group (4.4) (P < 0.0001). In experimental group gait ability on level surfaces increased 24.5% (P = 0.023) and in control group 39% (P= 0.001). Stair climbing ability increased 64% (P= 0.001) in experimental group but this ability was increased only 24.8% (P= 0.083) in control group. Conclusion: Muscle strength training is effective in improving muscle strength of involved lower extremity and stair climbing in the chronic stage of rehabilitation following stroke.