[Purpose] The purpose of this study was to investigate the changes in hip, knee and ankle kinematic
variables of the lower extremities at different gait speeds. [Subjects and Methods] Forty healthy subjects who had no
previous history of neurological, musculo-skeletal or other medical conditions that could affect gait were recruited.
The subjects were asked to walk 10 m down a walkway at three different gait speeds: normal gait speed, and selfselected
fast, and slow speeds. The experimental order was randomly chosen across these gaits. The hip, knee and
ankle kinematic data were evaluated using a VICON 3D motion analysis system and force plates. [Results] The
flexion peak and external rotation peak of the knee joint significantly increased with the increase of gait speed. The
plantarflexion peaks of the ankle joint significantly increased with increase of gait speed. However, none of the
kinematic data of the hip joint were significantly dependent on increase of gait speed. [Conclusion] The relationship
of the knee and ankle joint can be described as coupling motion which is dependent on gait speed. Our present
findings suggest that coupling motion of the knee joint and plantarflexion of the ankle joint significantly increase
with increase of gait speed. These results will provide important insight into gait mechanisms for the evaluation of
pathological populations.
Key words: Gait speed, 3D