charley horse charley horse a charley horse is a painful involuntary cramp in the legs and/or foot, lasting anywhere from a few seconds to a day. the term formerly referred more commonly to bruising of the quadriceps muscle of the anterior or lateral thigh, or contusion of the femur, that commonly results in a haematoma and sometimes several weeks of pain and disability. in this latter sense, such an injury is known as dead leg. charley horsespecialtysports medicine dead legs and charley horses are two different types of injuries: a charley horse involves the muscles contracting without warning, and can last from a few seconds to a few days. a dead leg often occurs in contact sports, such as football when an athlete suffers a knee (blunt trauma) to the lateral quadriceps causing a haematoma or temporary paresis and antalgic gait as a result of pain. colloquially, taking a hit in the thigh area (thigh contusion) can also be referred to as a charley horse or even simply a charley. cause charley horses have many possible causes directly resulting from high or low ph or substrate concentrations in the blood, including hormonal imbalances, dehydration, low levels of magnesium, potassium, or calcium (evidence has been mixed), side effects of medication, or, more seriously, diseases such as amyotrophic lateral sclerosis and neuropathy. they are also a common complaint during pregnancy. treatment relief is given by massaging or stretching the leg or foot in the opposite direction of the cramp. relief also comes from standing up, which serves to counter the muscle-tightening signal. notes "thigh contusion". fittoplay.org. retrieved 2022-03-16. "thigh contusion: symptoms, treatment and prevention". cleveland clinic. retrieved 2022-03-16. schwellnus mp, nicol j, laubscher r, noakes td (2004). "serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (eamc) in distance runners". british journal of sports medicine. 38 (4): 488–492. doi:10.1136/bjsm.2003.007021. pmc 1724901. pmid 15273192. sulzer nu, schwellnus mp, noakes td (2005). "serum electrolytes in ironman triathletes with exercise-associated muscle cramping". medicine & science in sports & exercise. 37 (7): 1081–1085. doi:10.1249/01.mss.0000169723.79558.cf. pmid 16015122. allen re, kirby ka (2012). "nocturnal leg cramps". american family physician. 86 (4): 350–355. pmid 22963024. miller tm, layzer rb (2005). "muscle cramps". muscle nerve. 32 (4): 431–42. doi:10.1002/mus.20341. pmid 15902691. s2cid 222021544. young gl, jewell d (2002). henderson s (ed.). "interventions for leg cramps in pregnancy". cochrane database of systematic reviews (1): cd000121. doi:10.1002/14651858.cd000121. pmc 7045417. pmid 11869565. "nocturnal leg cramps".