The kinematic and kinetic effects of solid, hinged, and no ankle–foot orthoses on stair locomotion in healthy adults

This study compared the effects of a unilateral solid ankle–foot orthosis (AFO), hinged AFO and no AFO (shoe) worn by healthy adults on pelvic angles, lower extremity joint angles, moments and powers, and temporal-spatial gait characteristics during stair locomotion. A convenience sample of 19 healthy adults participated in this repeated measures design with subjects serving as their own controls. Subjects ambulated on stairs wearing a left shoe and either a right solid AFO, hinged AFO or shoe. Kinematic and kinetic data were collected with motion analysis equipment and a force plate for the three conditions. Pelvic angles and right hip, knee and ankle angles, moments and powers during stance were compared to determine differences among the conditions. Subjects wearing either orthosis walked slower during stair locomotion and with a shorter right single limb support time during descent. Sagittal knee and ankle angles, moments and powers were similar in individuals wearing a hinged AFO or shoe during pull-up (PU) in ascent and controlled lowering (CL) in descent. Decreased ankle dorsiflexion angle, plantar flexion power, knee flexion angle and extensor moment were seen in subjects wearing a solid AFO as compared to a hinged AFO during PU in ascent and CL in descent. Findings contributed to understanding how biomechanical changes imposed at the ankle by a unilateral solid AFO resulted in more kinetic and kinematic compensations than the hinged AFO in healthy adults without the confounding effects of neuromuscular impairments.