Endurance Training

Endurance is the ability of an individual to perform repeated skeletal muscle contractions at a prescribed submaximal power output or speed. The capacity of an organ system to adapt to repeated bouts of physical activity so that its exercise capacity is improved is termed physical training. In this regard, [Page 393]previously healthy but sedentary individuals can, after only a few weeks of endurance training, exercise comfortably for prolonged periods at intensities that, prior to training, they could sustain for only a few minutes. For many years it was believed that this increased capacity for endurance was solely the result of training-induced cardiovascular adaptations, such as an increase in cardiac output and stroke volume accompanied by an enhanced delivery of oxygen to the working muscles. However, ...