Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

A concentric contraction is a type of muscle activation that causes tension on your muscle as it shortens. As your muscle shortens, it generates enough force to move an object. This is the most ...

Ken Nosaka is a Friend of The Conversation. One of the most popular new year’s resolutions is to exercise more. Many of us set ambitious goals requiring a big, regular commitment, but then abandon ...