Interval Training/Fartlek

Athletic events such as distance running predominantly use the body's aerobic energy system for production of adenosine triphosphate at a muscle-cellular level. While training for such events, athletes and their coaches look for methods to stress the aerobic system to stimulate the system to work more efficiently. This will often result in performance gains for the athlete as a consequence of the increase in mitochondrial density, better capillary network, and improved extraction of oxygen from the blood.

Stressing the aerobic system has risks in that exceeding the limits of aerobic power ...