knee-ankle interaction, one of the five major kinetic determinants of gait, which helps to minimize the displacement of the body’s center of gravity during the walking cycle. The knee and the foot work simultaneously to lower the body’s center of gravity. When the heel of the foot is in contact with the ground, the foot is dorsiflexed, and the knee is fully extended so that the associated limb is at its maximum length with the center of gravity at its lower point. Plantar flexion of the foot with the initiation of knee flexion maintains the center of gravity in its forward progression at about the same level, also helping to minimize the vertical displacement of the center of gravity. Knee-ankle interaction is often a factor in the diagnosis and treatment of various orthopedic diseases, deformities, and abnormal conditions and in the analysis and the correction of pathological gaits. Compare knee-hip flexion, lateral pelvic displacement, pelvic rotation, pelvic tilt.
