The Calves are comprised of 4 muscles; soleus, gastrocnemius, plantaris & popliteus.
Gastrocnemius and Soleus are primarily involved in plantar flexion or pointing the toe toward the ground. Plantaris does the same, but mainly assists gastroc during powerful movements, such as those involved with soccer or basketball. Popliteus mainly a stabilizer, but it also assists in unlocking the knee during extension.
If you are experiencing pain in the foot, heel, behind the knee or in your hamstrings your calves could be to blame.