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.

This is a common strength training technique that involves manipulating the muscle lengthening portion of an exercise, usually by slowing down the movement. Share on Pinterest Getty Images/Eugenio ...

Resistance, or weight training, is widely recommended in sports and rehabilitation as an effective exercise to increase muscular strength and size. This form of exercise involves applying resistance ...