Ruptured Calf Muscle: When there is pain that is sudden in the muscle of the calf during any activity it could be caused by a torn or pulled calf muscle. This is referred to as a calf pull or strain and it happens when a portion of the muscles of the lower portion of the leg become stretched far beyond their normal ability to handle the tension. This stretching may cause small micro tears to the fibers in the muscle, or in a severe injury, a total rupture of the fibers of the muscles.

A much less severe, but often just as painful, cause of pain in the calf is when the calf muscle spasms or cramps. This is a contraction of the muscle that is involuntary, but short-lived, and it can be so strong that it creates a bruise.

Calf pull or strain will frequently happen during acceleration or a change in direction that is abrupt while running. A calf muscle that is torn might contract or spasm so forcefully that even the toes automatically will point down. Bruises will develop above the area that is injured and in the ankle and foot because of blood pooling from bleeding internally.

Strains of the calf can be very severe to very mild and are normally classified as follows: calf strain grade 1 is when the muscle is stretched and causes some small micro tears in the fibers of the muscle. Total recovery takes about 2 weeks; calf strain that is grade 2 is when there is partial tearing of the fibers of the muscle. Total recovery takes about 5 to 8 weeks; calf strain grade 3 is the most severe with a total rupture or tearing of muscle fibers in the lower leg. Total recovery can take 3 to 4 months and with some grade 3, surgery can be needed.