Stretching is a form of physical exercise in which a specific skeletal muscle (or muscle group) is deliberately stretched.
Stretching is a form of physical exercise in which a specific skeletal muscle (or muscle group) is deliberately stretched, often by abduction from the torso, in order to improve the muscle's felt elasticity and reaffirm comfortable muscle tone.1 The result is a feeling of increased muscle control, flexibility and range of motion
See, Wikipedia Stretching