Eccentric Exercise Is Powerful but Can Be Painful

Abstract

Your muscles can contract in different ways: when you walk upstairs, the muscles at the fronts of your thighs shorten (concentric contraction), whereas when you walk downstairs, they lengthen (eccentric contraction). Concentric contractions require more oxygen and thus make you burn more calories. Eccentric contractions are easier but break parts of the muscle and make you feel sore for several days. If you repeat eccentric exercises, however, your muscles will probably get bigger and stronger than they would by repeating concentric contractions. Most physical activities (like running and jumping) include both concentric and eccentric phases. Scientists have designed tools to study each type of muscle contraction, such as eccentric cycling, which uses a bike on which you must resist the pedals as they are driven backward by an engine.