Swimming on the Back
Swimming on the back is one of the simplest of the natatorial exercises, and one of the easiest methods to learn, besides being absolutely necessary in life-saving, as well as useful as a means of resting after swimming a long while on the breast or side. The movements of the legs are very much the same as in the breast stroke, except that the knees are kept farther apart. The best way to learn to swim on the back is to place yourself in the water on the back, the same as you would when floating. This position can be easily attained by holding the arms straight down close to the sides, the hands pointing toward the feet, and by giving a few sculling movements with the hands, you will at once get into a good floating position. Now slowly open the legs apart, while at the same time extending the arms beyond the head and bring the legs together with a vigorous kick, holding the arms beyond the head for an instant until all the momentum from the kick is expended. At the second movement the arms are brought back to their former position, describing an arc and catching the water with the palms of the hands somewhat like an oar, which helps to send the swimmer ahead, repeating the movements as before.
When tired, swimming on the back is useful as a means of resting the muscles used in the other strokes.