A leg cramp is an involuntary, sustained tightening (contraction) of one or more of your muscles. By far the most common muscles that cramp are the hamstrings (back of thigh), quadriceps (front of thigh), and the gastrocnemious (calf). Cramps in the feet are also common. Leg cramps often occur at night while sleeping and can range from mildly painful and annoying to excruciating and debilitating. A pregnant woman once reported that the hamstring cramps she suffered with during her pregnancy were more painful then the delivery of the baby.
Massaging the cramped muscle increases circulation in the tissue, providing a rush of new fluid to bathe and relax the tense muscle. Swedish neuromuscular and myofascial release techniques are particularly effective. However, a therapist must be aware that a client with a cramped muscle may be in too much pain for physical manipulation of the muscle.