ObjectiveSpastic paretic stiff-legged gait, defined as reduced knee flexion in swing, has previously been attributed solely to spastic quadriceps activity. In earlier work, the authors suggested that reduced knee flexion in swing can be attributed to other indirect factors, such as poor hip flexion and abnormal foot-ankle function during gait. The present study was undertaken to determine whether toe-walking, which often occurs in conjunction with stiff-legged gait, in and of itself, might explain some of the reduced knee flexion in swing.DesignAn analysis was performed of three-dimensional kinematic data collected from able-bodied subjects while walking on their toesvs.normal heel-toe walking.ResultsPeak knee flexion was reduced significantly compared with normal heel-toe walking (42.2 ± 8.9 degrees toe-walkingvs.59.2 ± 5.7 degrees heel-toe walking;P< 0.00001).ConclusionsThis finding, which occurred when controlling for walking speed, may be clinically relevant for patients who have both a toe-walking and a stiff-legged gait pattern. Some of the reduced knee flexion in swing may be merely a consequence of toe-walking, rather than a result of other causes, such as intrinsic spasticity or abnormal muscle firing about the knee.