Muscle strain is an injury to a muscle or a tendon, which is the fibrous tissue that links muscles to bones. Minor injuries may just cause a muscle or tendon to overstretch, but more serious injuries may cause partial or total rips in these tissues. Muscle strains can be divided into three main categories based on how long it takes for the patient to recover: acute, chronic, and recurrent. Acute muscle strains usually occur when a muscle is overstretched as a result of a single traumatic event, such as a fall. The injured muscle quickly repairs itself, allowing the person to return to normal activities within a few weeks. Chronic muscle strains develop over time due to repeated movements or acts that stress the muscle past its repair capacity. These injuries may not heal properly because the body is trying to protect itself from further damage. Recurrent muscle strains happen because the injured muscle does not have enough time to fully heal before being used again. For example, if you repeatedly lift weights without giving your muscles time to recuperate, you will eventually develop muscle strains. The severity of a muscle strain depends on how much force is applied to it and for how long. If the muscle is stretched beyond its natural limit, it has no choice but to tear itself apart through necrosis (death) of some of its fibers. This is called a "complete" rupture.