Many infants wear paper diapers during the gait-forming period. We measured electromyography during walking in 10 infants under 3 conditions, and analyzed the motion: naked, wearing a paper diaper, and wearing a paper diaper containing physiological saline. The gait test was repeated in the same infants after 4 months to investigate changes in the influence of paper diapers. In the first test, the muscle burden was not significantly increased by wearing a paper diaper alone, but that on the biceps femoris was significantly increased by a paper diaper containing saline. In the second test 4 months later, the burden on the biceps femoris due to a paper diaper and that containing saline were significantly decreased. Motion analysis detected the minimum distance between the bilateral knees was significantly broadened when wearing a diaper containing saline in the second test.
