The effects of body weight on the soleus H-reflex modulation during standing

Objective: We examined how the soleus H-reflex is affected by the changes in limb loading by testing subjects on a body weight support system during standing. Design: Twenty-two healthy subjects (10 males and 12 females) were recruited for this study. The size of the soleus H-reflex was measured in six different limb loading conditions: 100%, 90%, 80%, 70%, 60%, and 50%. One-way repeated measure ANOVA was used (p< 0.05) to compare the H/M ratios among the six different load conditions. Results: The amplitudes of the soleus H-reflex decreased significantly as the amount of body weight load decreased. Conclusions: Findings of this study suggest that the levels of body weight load in pre- and post-test conditions should be consistent when H-reflex testing is adapted as an outcome measure of rehabilitation intervention for patients with central nerve system lesion such as partial body weight supported gait training.