Introduction
Propulsion is an important aspect of swimming.
The purpose is to be as efficient as possible, using muscles only when necessary and avoiding the waste of energy.
The majority of the propulsion studies in swimming promotes front crawl. If we look closely at the underwater arm movement and the motor path of the hand, we see that the underwater breastroke and the front crawl have very similar, if not identical, motions and pathways.
The article below expands on this topic.