The most common causes of foot and leg cramps are overuse and underuse. Overusing the muscles can tire them out, and when muscles tire, they tighten up. Cramps are likely to occur when muscles are tight and tired, so over-training and over-exercising can lead to problems. Not using the muscles enough can lead to muscle weakness, and weaker muscles are more likely to become tired than strong ones. Living a sedentary lifestyle is likely to lead to the weakening or degradation of muscles, which can in turn lead to tightness that will cause cramps.
Dehydration and loss of electrolytes in the muscles can also cause foot and leg cramps. Muscles need the proper delivery of oxygen in order to function correctly, and if the body is low on fluids, that delivery slows or stops. Drinking plenty of fluids before, during, and after physical activity can help prevent cramps by helping to prevent this problem. The legs and feet are most susceptible to cramping when dehydration occurs, so it is important for people to stay hydrated to prevent damage to the muscles.
Electrolytes are chemicals in the body that conduct electricity and are responsible for helping regulate muscle and nerve activity in the body. When the body becomes depleted of electrolytes, it may suffer muscle cramps and other problems. Salt, calcium, and magnesium are common electrolytes used in the body. An athlete may choose to modify his or her diet to ensure that he or she is getting enough of these minerals, or he or she may choose to take vitamin and mineral supplements that can supply the body with the necessary electrolytes. A lack of electrolytes in the body may also exacerbate dehydration, leading to cramps.
Other factors that may contribute to foot and leg cramps include certain medications, improper training, and injury. Medications are often likely to cause dehydration, which can in turn lead to muscle cramps. Injuries to the legs or other parts of the body may lead to cramps as well. An injury to a hip, for example, may put extra strain on the foot and leg opposite the injured hip, causing the muscles in those areas to strain or contract abnormally. Improper training can lead to muscles becoming overtaxed, thereby making them susceptible to cramping.