THE RELATION BETWEEN LIMB LOADING AND CONTROL PARAMETERS OF GAIT INITIATION IN PERSONS WITH STROKE

Objective: This study investigated the relation between limb loading a nd selected characteristics of gait initiation in patients after strok e. Subjects and Setting: Thirteen patients attending a rehabilitation clinic volunteered for the study. Design: For the description of clini cal features, patients were divided into two groups dependent on the a mount of body weight shared by the involved limb during stance before gait initiation. Main Outcome Measures: Patients performed six trials of gait initiation with either their involved or noninvolved limb on a force platform. Peak ground reaction forces and bilateral tibialis an terior and gastrocnemius electromyographic (EMG) activity were used fo r group comparison. Results: All patients showed the correct loading a nd unloading characteristics in the vertical and medial-lateral direct ion during gait initiation. Strong correlations were noted between ini tial limb loading and ground reaction forces during gait initiation (r = .79 to .95). Changes in ground reaction forces were significantly l ess (p < .001) for those patients who demonstrated decreased weight be aring on their involved limb before gait initiation. These patients we re also unable to generate forward momentum, as evidenced by the fore- aft ground reaction force, with the involved limb. For all patients, i ncreased gastrocnemius activity was noted in the stance (noninvolved) limb. The data are further discussed in regard to the relationship of the interaction of bilateral EMG activity and ground reaction forces. Conclusion: This study suggests that there is a correlation between sy mmetrical weight bearing and the ability to provide those forces that generate forward momentum in the initiation of gait. (C) 1995 by the A merican Congress of Rehabilitation Medicine and the American Academy o f Physical Medicine and Rehabilitation