The biomechanics of using a walker for the partial weight bearing gait and as a method for gradually increasing the muscle activation level were examined with a force plate and surface electromyography. The results showed that the weight bearing force during gait with a walker is determined by the flexion angle of the hip joint. The value remains constant for each stride, indicating that a walker can be used for the partial weight bearing gait. Moreover, the muscle activation levels in the rectus femoris muscle and biceps femoris muscle per unit time during normal gait and gait with a walker with varying hip joint flexion angles were found to be correlated with the weight bearing force and to be constant for each stride. In addition, the muscle activation level was consistent with the level observed during the open kinetic chain resistance exercise with a specific loading level. These findings suggest that normal gait and gait with a walker may be applicable as a method for gradually increasing the muscle activation level.