The calf, or lower leg, consists of two major muscles: the gastrocnemius -- the large muscle on the back of the calf -- and the soleus -- the smaller muscle that runs underneath the gastrocnemius. Calf muscle tears, or strains, are common in athletes with tight calf muscles. Strains are graded on a scale of 1 to 3, from mild to severe, respectively. It is important to recognize the signs and symptoms of a torn calf muscle so you can seek appropriate assistance.
Grade 1 Strain
A Grade 1 strain is a minor tear, involving up to 10 percent of muscle fibers. With a this type of strain you feel a sharp pain upon injury, followed by mild pain and localized tenderness. You may still be able to exercise, walk or run, but it will most likely feel tight and tender. Typically, this type of strain will last for two to five days.
Grade 2 Strain
A Grade 2 strain is a moderate tear, involving 10 to 50 percent of the fibers. This injury is more intense and stops your activity with a sudden, sharp pain in the back of your lower leg. Your calf will feel weak, and it will hurt to walk or make any kind of movement with the affected leg. You may experience some swelling and moderate bruising. Your calf will most likely feel tight and sore for a week or more.
Grade 3 Strain
A Grade 3 strain is the most serious tear, involving 50 to 100 percent of the muscle fibers, or a complete rupture. A Grade 3 strain is signaled by a severe, immediate pain in the back of your leg. Sometimes you will feel a popping sensation. You will experience disability. Because you will be unable to contract or flex your calf muscles at all, walking will be difficult or impossible. You will notice considerable bruising and swelling, and your leg will be painful to the touch. If your calf muscle has completely ruptured, you can often see the muscle bunched up at the top of the calf.
Your medical provider will palpate the muscles and aponeurosis -- tendon-like tissue along the muscle -- to identify tenderness, defects, swelling, thickening or masses, according to J. Bryan Dixon in "Gastrocnemius vs. Soleus Strain: How to Differentiate and Deal with Calf Muscle Injuries." The gastrocnemius arises from above the knee and the soleus muscle originates below the knee, making knee flexion and extension diagnostic criteria for determination of the muscle involved in the injury.