The sidestroke is a swimming stroke, so named because the swimmer lies on one's side with asymmetric arm and leg motion.
[2] A swimmer tired of exercising one side can turn over and use the other, the change of action helping the limbs to recover.
In ordinary swimming on the right side, the left arm moves gently in the water, almost at rest.
Until within the last few years, it was generally assumed that breast or belly swimming was the swiftest process, but this opinion has proved fallacious.
The sidestroke is now universally acknowledged as the superior method and young swimmers do well to practice it accordingly.Sidestroke evolved in ancient times from swimmers who discovered that it was painful to swim breaststroke with the head above the water.