Hand force is directly related to swimming velocity - the greater the force, the faster the velocity. This swimmer steadily increases hand force in the beginning of his breaststroke.

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As he moves his arms from Position 1 to Position 2, the elbows stay below the shoulders and the hands stay below the elbows. This motion insures that the arms are in a mechanically advantageous (strong) position throughout the range of motion. A steady increase in force results. (The vertical lines on the graphs are synchronized with the video image.)