Kinesiological study of push-up motion using a three-dimensional floor reaction on a force plate.

To find an effective way to handle wheelchairs, 3-dimensional floor reactions of the hand and angular deviation of the elbow and wrist joints during push-up motion were studied in 10 healthy men. The push-up was carried out using 3 hand positions (fist, finger and palm) and a push-up device. In all hand positions, anteroposterior force (Fx) and the mediolateral force (Fy) appeared after the vertical force (Fz). The end point of Fx and Fy was observed before that of Fz. Among the 4 different hand positions, Fx and Fy appeared first in the palm, followed by the finger and fist positions, and lastly in the push-up devices. The results indicate that the more unstable pushing-up the body is, the earlier and longer Fx and Fy are. Thus, Fx and Fy are considered to be good indicators of body balance during the push-up motion. The elbow joint showed a hyperextended position only when using the palm position in the maintenance phase. The wrist joint showed palmar flexion only when using the fist position.