The healing time for a torn muscle varies from two weeks for a mild tear to two months or more for a severe tear, according to Johns Hopkins Medicine. Medical providers refer to torn muscles as muscle strains.
FitDay reports that there are three types of muscle strain. The first is a first-degree strain, which affects less than 5 percent of the respective muscle. This type is only mildly painful, does not affect strength or range of motion and usually heals within a few weeks. A second-degree strain is a partial tear that causes pain with each contraction. This type tends to take a month or more to heal. The worst type, a third-degree strain, is a tear along the entire width of a particular muscle, making it impossible to contract it. This type often requires surgery to stop internal bleeding and generally does not heal for several months.
According to Johns Hopkins Medicine, those who warm up with light stretching and walking or jogging before exerting themselves are less likely to tear their muscles. Many studies on muscle strains show that a heated muscle is less prone to strains than a muscle that is exerted without the benefit of a warm-up.