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.

What Are Eccentric and Concentric Contractions? Eccentric contractions occur when a muscle lengthens under load, such as lowering a dumbbell during a biceps curl. Concentric contractions happen when ...

Correspondence to Dr M Roig, Muscle Biophysics Laboratory, University of British Columbia, Vancouver, Canada V5Z 1L8; markredj{at}interchange.ubc.ca The aim of this systematic review was to determine ...