Biomechanical analysis of gait termination in 11-17year old youth at preferred and fast walking speeds

In populations where walking and/or stopping can be difficult, such as in children with cerebral palsy, the ability to quickly stop walking may be beyond the child's capabilities. Gait termination may be improved with physical therapy. However, without a greater understanding of the mechanical requirements of this skill, treatment planning is difficult. The purpose of this study was to understand how healthy children successfully terminate gait in one step when walking quickly, which can be challenging even for healthy children. Lower extremity kinematic and kinetic data were collected from 15 youth as they performed walking, planned, and unplanned stopping tasks. Each stopping task was performed as the subject walked at his/her preferred speed and a fast speed. The most significant changes in mechanics between speed conditions (preferred and fast) of the same stopping task were greater knee flexion angles (unplanned: +16.49±0.54°, p=0.00; planned: +15.75±1.1°, p=0.00) and knee extension moments (unplanned: +0.67±0.02N/kgm, p=0.00; planned: +0.57±0.23N/kgm, p=0.00) at faster speeds. The extra range of motion in the joints and extra muscle strength required to maintain the stopping position suggests that stretching and strengthening the muscles surrounding the joints of the lower extremity, particularly the knee, may be a useful intervention.