If you ask most people what their general fitness goals, the answer often is to “tone up and get in shape.” We have come to accept the term “tone” to mean muscular definition, or the appearance of a well-defined muscle. The term is actually short for tonus, which is the technical term used to describe a state of contraction in a normally functioning muscle. Using a muscle repeatedly during a strength training exercise will leave that muscle in a state of semi-contraction, creating the defined appearance we have come to expect as the result of exercise.