Elbow load during pushup at various forearm rotations

Objective. Elbow joint loading was evaluated during pushup exercises at various forearm rotations. Design. Subjects were asked to perform pushup in various forearm rotations: neutral, 90° internal rotation, and 90° external rotation. Background. Training with pushup exercise is good for the muscles and joints of the upper extremities. However, excessive shear forces on the elbow might lead to injuries to either normal trainees or to handicapped people, especially for those who rely on elbow prosthesis.Methods. The kinematics and kinetics of the elbow joint were investigated under various forearm rotations. Results. The loading biomechanics of the elbow joint differed with various forearm rotations. It was noted that greater posterior and varus forces of the elbow are encountered with internal rotation of the hand position and, consequently, full forearm pronation. Conclusions. Pushup with hands in internally rotated position should be prevented so as to avoid excessive shear forces or moments. Relevance. Knowledge of elbow kinematics and kinetics may be helpful in preventing injuries by reducing the elbow shear force with changes of forearm rotation.