Foot and ankle kinematics and ground reaction forces during ambulation

Background: Assessing patients with foot and ankle disorders by observation of gait is dependent on the examiner's experience and cannot provide information about three-dimensional movement, forces, or motion of segments of the foot. Gait analysis models usually consider the foot as a rigid body and study the foot and ankle as a unit. These models are adequate to describe ankle sagittal plane mechanics but are limited in their ability to provide accurate analysis in the other planes or of segments of the foot. They are, therefore, less effective for objective assessment of foot and ankle disorders than multisegment foot models. Methods: We performed gait analysis using foot-specific analysis methods and evaluated kinematics, ground reaction forces, temporal force factors, and time-related gait factors in 20 normal subjects during level walking. Eleven reflective markers were applied to the foot and leg, and ten cameras and force plates were used. Subjects were tested in athletic shoes. Results: A three-segment model was constructed to determine three-dimensional motion in the sagittal, coronal, and transverse planes. This model enabled the determination of calcaneal-tibial (ankle-hindfoot complex) and metatarsal-calcaneal (midfoot) movement in three planes. Ground reaction forces, temporal force factors, cadence, stance time, swing time, and percentage of stance time were determined. Conclusions: These data provide baseline information for assessment of patients with disorders of the ankle and foot.