Swimming is defined as moving through water using fins, tails, or limbs. The document outlines some of the benefits of swimming such as weight loss, whole body workout, and improved shape. It also discusses swimming rules regarding proper attire and safety for non-swimmers. The backstroke is described as a stroke performed on one's back using alternating overarm strokes and a flutter kick. The effects of backstroke include having a powerful start and glide and restrictions on underwater arm movements. Overall, swimming provides postural, cardiovascular, and circulatory benefits.