The sport of swimming demands not only muscular endurance but strength and lung capacity. Among the many rewards of the sport are full-body conditioning and aerobic fitness.
When you swim, your biceps, triceps, quadriceps and calf muscles must all contribute to propelling you through the water. With each stroke you take, these muscles must repeatedly contract in order for you to make headway. This requires muscular endurance, which is the ability of muscle groups to continually contract during the course of your swim.
Muscular endurance enables you to swim for a longer time period. As you swim longer distances, you increase your muscular endurance. The repetitive dynamic contraction of each muscle group you use in each of the four competitive strokes--freestyle, backstroke, breaststroke and butterfly--strengthens your muscles so they can perform better during your next swim.
While "dry" sports such as running and bicycling require muscular endurance, the sport of swimming requires even more. The resistance which a swimmer encounters in the water is greater than the resistance athletes face on land. Swimmers must compensate for the water's "drag" with maximised strength, endurance, and stroke technique.
Competitive swimming requires more than muscular endurance. Sprinting demands strength and technique for ultimate success. Respiratory conditioning is also critical.
Muscular endurance allows swimmers to continue practicing their sport into old age. Because the body is buoyed by water, swimming is a non-weight bearing activity which is an excellent conditioning exercise for all ages and for those recovering from many types of physical injuries