Playing tennis builds muscle power, and improves physical capacity. Since the average point in tennis is between 4 and 12 seconds long, tennis allows players to fully engage their anaerobic (or power) system.
During the short duration of a tennis point, the body relies on the energy provided by a starch called glycogen that is stored in the muscles. This form of metabolism works without the aid of oxygen and a player goes into what scientists call oxygen debt. Following this, the body recovers to replenish this “debt” through improved heart and lung function.
The natural repetition provided by tennis allows the body to adapt by building muscle and improving heart-lung function. In fact, Legros and colleagues found that the rate of phosphocreatine concentrations (PC) (a measure of anaerobic capacity/fitness) recovery was much faster in tennis players or active people than in sedentary subjects.