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 5 x 10 meters during the A₁ phase and 3 x 10 meters during all subsequent phases. This procedure was repeated for five consecutive days. Two lbs (B₁) and 6 lbs (B₂) weight cuffs were attached to the distal lower hemiparetic extremity and randomized over the two B phases. Control (A₁, A₂, A₃) and intervention (B₁, B₂) 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 (χ² = 34.187; p < 0.001). However, with the exception of a carry-over effect between the A₁ (0.86 m/sec) and A₂ (0.89 m/sec) phases in one subject (p = 0.043) no significant carry-over effects were found on ensuing A₂ and A₃ 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.