Analysis of Gait Propulsion During the Ankle and Forefoot Rocker Sub-phases

Abstract

Background: The theorized role of the plantar flexors and modes of propulsion during normal gait vary. They have not been sufficiently defined objectively outside of the well-defined eight phase of gait. Analyzing gait with regard to sub-classes within the foot rockers may better define variation in healthy individuals. Research Objective: Characterize gait parameters in persons with propulsive and non-propulsive gaits. Methods: Thirty-four healthy adults were assigned to propulsive and non-propulsive groups. Participants ambulated three times at a self-selected speed. Data were collected using a high speed camera, pressure sensitive walkway, and electromyography (EMG). Results: Twelve participants demonstrated unique objective biomechanical measures associated with propulsion and the remaining with non-propulsion. Significant differences were discovered between the two groups in time spent of the ankle and forefoot rockers (p<0.006). The propulsive group had a 12% faster heel rise than to the non-propulsive group (p=0.000). Significant time to peak (TTP) differences were found between groups for the medial gastrocnemius and lateral gastrocnemius muscles during the ankle and forefoot rockers and for the soleus TTP during the forefoot rocker (p<0.0025). Significance: This study established objective gait parameters and preliminary construct validity for propulsive and non-propulsive gait in healthy normal individuals.