Muscle tears occur when a person doesn't properly prepare before lifting weights, or tries to lift more weight than the body can handle. A muscle tear occurs when a person's muscle rips when making an unnatural movement, or when a muscle is stretched to quickly. Before starting any exercise or weight training program, consult with a professional who can help design a special program, and teach you proper techniques to help avoid muscle tears. Also, consult with a physician to check for any underlying problems before starting a weight lifting program.