Effects of overloading of the lower hemiparetic extremity on walking speed in chronic stroke patients: A pilot study

The objective of this pilot study was to investigate the carry-over effects on comfortable walking speed after overloading the lower hemiparetic extremity in chronic stroke patients. A single subject research study was conducted using a withdrawal design (A-B-A-B-A) on three patients with ischaemic middle cerebral artery infarction. Chronic stroke patients were recruited with stage 3 or 4 Fugl-Meyer scores in the lower extremity and the ability to ambulate independently without walking aids. Based on this withdrawal design, the daily procedure included walking at comfortable speeds 5x10 meters during the A_1 phase and 3x10 meters during all subsequent phases. This procedure was repeated for five consecutive days. Two lbs (B_1) and 6 lbs (B_2) weight cuffs were attached to the distal lower hemiparetic extremity and randomized over the two B phases. Control (A_1, A_2, A_3) and intervention (B_1, B_2) phases were alternated with brief resting periods. Mean comfortable walking speed for 10 meters constituted the outcome variable. All patients showed significant differences between phases (chi^2 = 34.187; p<0.001). However, with the exception of a carry-over effect between the A_1 (0.86 m/sec) and A_2 (0.89~m/sec) phases in one subject (p=0.043) no significant carry-over effects were found on ensuing A_2 and A_3 control phases. Although gradual improvements in comfortable walking speed between subsequent days were found the present pilot study did not demonstrate favorable group effects on comfortable walking speed as a result of limb overloading.