Gait analysis and bivalved serial casting of an athlete with shortened gastrocnemius muscles: a single case design.

Muscle tightness may predispose an athlete to injury. Stretching may help prevent injury by increasing joint passive range of motion and perhaps by increasing ankle range of motion during gait. The purpose of this study was to determine if bivalved serial casting and a positioning program would increase the total dynamic ankle range of motion without increasing the amount of compensatory foot pronation used during gait of an athlete with shortened gastrocnemius muscles. The subject was a 21-year-old male athlete. A three-dimensional camera-based kinematic system was used to collect functional dynamic ankle range of motion data. The Musgrave Footprint system was used to determine the relative amount of foot pronation (by measuring the pronation-supination index and dynamic foot angles). Data were collected for baseline, postintervention, and withdrawal phases. Data were then graphed and descriptively interpreted using means, standard deviations, trend, and level analyses. Following the treatment, the subjects showed an increase in mean total dynamic ankle range of motion without an increase in dynamic foot pronation. Eight weeks after treatment, the increase in mean total dynamic ankle range of motion was maintained and the pronation measurement did not change.