背泳におけるプルの研究  [in Japanese] A Study on the Back Stroke Arm Pull  [in Japanese]

The elbow bend is accompanied by a rotation of the upper arm which prevents the elbow from dropping. After this point of maximum elbow bend has been reached, the hand pushes backward and downward in a quarter circle motion with the palm pushing toward the bottom of the pool at the end of the arm pull. The last half of the pull is achieved by extension of the elbow, a continued medial rotation and adduction of the upper arm. The downward push at the end of the pull causes the body to roll on its longitudinal axis. In many cases the hand finishes a foot below the hips because the palm is facing inward toward the thigh as it pushes downward. The push downward is a fast movement and is close to a throwing motion in terms of its acceleration. The pull, from beginning to end, has described the pattern of a flattened 'S'.