According to About.com, a minor calf strain can heal in as few as seven days, while a severe calf strain can take up to three months to heal. The healing time depends on the severity of the injury.
A calf strain occurs when the gastrocnemius muscle is stretched too far. About.com explains that in severe strains the muscle fibers are torn, and in rare occasions the injury can cause the muscle to tear completely.
Symptoms of calf strain range from mild discomfort to swelling, bruising, and difficulty running and jumping. People with severe calf strains may not be able to walk. Muscle spasms and pronounced bruising may also occur. The main treatments for a calf strain are rest, gentle stretching and the application of ice to the injured area, states About.com.