As the elbow flexes at the beginning of the freestyle pull, does the forearm get vertical?
If the elbow is flexed and the forearm is vertical, the hand must be to the outside of the shoulder. As force is applied during this motion, torque is generated and the body twists about the antero-posterior (front to back) axis. The twisting increases resistance and slows swimming velocity. It is more effective to diagonally orient the forearm during the pull phase, so that the hand passes beneath the head. The swimmer will benefit from the improved mechanical advantage of the elbow angle and have the arm in a stronger position to generate force on the push phase.
