Muscle
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Introduction Muscle cramping is probably an inevitable experience for most runners and other endurance athletes and has to be one of the more common questions asked by patients in our sports medicine clinic. I'll cover the basics about the causes of the typical type of muscle cramps, as well review some of the medical literature regarding current concepts in treatment and prevention and try to explain some of the myths and misinformation about cramps. What is a muscle cramp? Muscle cramps or cramping is a condition that most runners have experienced. It is usually defined as a spontaneous and painful contraction or spasm of a muscle or a muscle group such as the calf muscles or hamstrings. Are there different types of muscle cramps? Yes, and also a number of different causes of muscle cramps. Muscle cramps occur in the welltrained athlete, the elderly and is also more common in women during pregnancy. Severe electrolyte or chemical deficiencies or imbalances may also cause muscle cramping, in addition to underlying neuromuscular disorders. The wide variety of people whom experience muscle cramps suggest that there are multiple or different factors or triggers for cramps. The most common type of muscle cramp seen in athletes is exercise-associated muscle cramps (EAMC). Surveys of marathon runners and Ironman triathletes have reported a prevalence of muscle cramps of 30-50% and 67% respectively (Schewellnus). What are the causes of muscle cramps? Schwellnus and others have suggested that EAMC is actually a result of muscle fatigue and not due to other causes such as dehydration or electrolyte imbalance. Their current concept for the source or etiology of EAMC is that an altered or abnormal spinal reflex activity produces muscle cramping. As the muscle fatigues, the amount of relaxation time in between muscle contractions lengthens. If the relaxation time is too long, or a high rate of muscle contraction is required, such as during running, then muscle cramping may result. Cramping may also be a protective mechanism to prevent further injury to fatiguing or damaged muscle tissue. What about sodium and other electrolytes? Sodium and other electrolytes such as potassium and magnesium have been mentioned in the
past as possibly causing exercise-induced muscle cramps, although there is little evidence to support electrolyte imbalance as a cause. The original work looked at miners and other workers exposed to high-heat environment. Two more recent studies by Nicol and Maughan have looked specifically at endurance athletes and were not able to identify an association between muscle cramps and changes in the blood levels of specific electrolytes. However, in some cases, runners and other athletes that have an excessively high sodium sweat rate combined with a low-sodium intake may suffer from cramps due to low sodium levels. Who is more likely to cramp? Which athletes are more at risk for EAMC? Manjra studied over 1300 marathon runners and found the following risk factors for EAMC among the runners: Older age of the athlete Longer running history Higher Body-Mass Index (BMI) Less time spent stretching, or irregular stretching habits Family history of muscle cramps
Manjra also found that the marathon runners were able to identify certain conditions that either appeared to aggravate or precipitate EAMC. These conditions included: Duration (or distance) of running Increased intensity of running Running hills Subjective feelings of muscle fatigue or poor race performance. What are effective treatments for muscle cramps? Treatment for exercise-induced muscle cramps primarily focuses upon passive stretching of the affected muscle groups, as well as correcting any identifiable muscle imbalances and weaknesses. Proper nutrition and hydration during competition and training are also important by preventing early fatigue and susceptibility to muscle cramping.
References Bentley S, Exercise-induced muscle cramp. Proposed mechanisms and management. Sports Med 1996 Jun;21(6):409-20 Manjra SI, Muscle cramps in athletes, Sports Medicine thesis, University of Cape Town
Maughan RJ, Exercised-induced muscle cramp: A prospective biochemical study in marathon runners, Journal of Sports Sciences, 4 , 31-34 Schewellnus MP, Derman EW, Noakes TD, Aetiology of skeletal muscle 'cramps' during exercise: A novel hypothesis. Journ Sports Sci, 1997, 15, 277-285 Dr. John Martinez is a primary care sports medicine physician and medical director of Coastal Sports & Wellness Medical Center, a sports injury clinic in San Diego, CA. Visit us at http://tiensshop.co.uk/Muscle-Cramp-c2_15.html Find more articles like this at http://tiensshop.co.uk/Muscle-Cramp-c2_15.html Copyright 2008
==== ==== For more information on Muscle Cramp please check this out; http://tiensshop.co.uk/Muscle-Cramp-c2_15.html ==== ====
Introduction Muscle cramping is probably an inevitable experience for most runners and other endurance athletes and has to be one of the more common questions asked by patients in our sports medicine clinic. I'll cover the basics about the causes of the typical type of muscle cramps, as well review some of the medical literature regarding current concepts in treatment and prevention and try to explain some of the myths and misinformation about cramps. What is a muscle cramp? Muscle cramps or cramping is a condition that most runners have experienced. It is usually defined as a spontaneous and painful contraction or spasm of a muscle or a muscle group such as the calf muscles or hamstrings. Are there different types of muscle cramps? Yes, and also a number of different causes of muscle cramps. Muscle cramps occur in the welltrained athlete, the elderly and is also more common in women during pregnancy. Severe electrolyte or chemical deficiencies or imbalances may also cause muscle cramping, in addition to underlying neuromuscular disorders. The wide variety of people whom experience muscle cramps suggest that there are multiple or different factors or triggers for cramps. The most common type of muscle cramp seen in athletes is exercise-associated muscle cramps (EAMC). Surveys of marathon runners and Ironman triathletes have reported a prevalence of muscle cramps of 30-50% and 67% respectively (Schewellnus). What are the causes of muscle cramps? Schwellnus and others have suggested that EAMC is actually a result of muscle fatigue and not due to other causes such as dehydration or electrolyte imbalance. Their current concept for the source or etiology of EAMC is that an altered or abnormal spinal reflex activity produces muscle cramping. As the muscle fatigues, the amount of relaxation time in between muscle contractions lengthens. If the relaxation time is too long, or a high rate of muscle contraction is required, such as during running, then muscle cramping may result. Cramping may also be a protective mechanism to prevent further injury to fatiguing or damaged muscle tissue. What about sodium and other electrolytes? Sodium and other electrolytes such as potassium and magnesium have been mentioned in the
past as possibly causing exercise-induced muscle cramps, although there is little evidence to support electrolyte imbalance as a cause. The original work looked at miners and other workers exposed to high-heat environment. Two more recent studies by Nicol and Maughan have looked specifically at endurance athletes and were not able to identify an association between muscle cramps and changes in the blood levels of specific electrolytes. However, in some cases, runners and other athletes that have an excessively high sodium sweat rate combined with a low-sodium intake may suffer from cramps due to low sodium levels. Who is more likely to cramp? Which athletes are more at risk for EAMC? Manjra studied over 1300 marathon runners and found the following risk factors for EAMC among the runners: Older age of the athlete Longer running history Higher Body-Mass Index (BMI) Less time spent stretching, or irregular stretching habits Family history of muscle cramps
Manjra also found that the marathon runners were able to identify certain conditions that either appeared to aggravate or precipitate EAMC. These conditions included: Duration (or distance) of running Increased intensity of running Running hills Subjective feelings of muscle fatigue or poor race performance. What are effective treatments for muscle cramps? Treatment for exercise-induced muscle cramps primarily focuses upon passive stretching of the affected muscle groups, as well as correcting any identifiable muscle imbalances and weaknesses. Proper nutrition and hydration during competition and training are also important by preventing early fatigue and susceptibility to muscle cramping.
References Bentley S, Exercise-induced muscle cramp. Proposed mechanisms and management. Sports Med 1996 Jun;21(6):409-20 Manjra SI, Muscle cramps in athletes, Sports Medicine thesis, University of Cape Town
Maughan RJ, Exercised-induced muscle cramp: A prospective biochemical study in marathon runners, Journal of Sports Sciences, 4 , 31-34 Schewellnus MP, Derman EW, Noakes TD, Aetiology of skeletal muscle 'cramps' during exercise: A novel hypothesis. Journ Sports Sci, 1997, 15, 277-285 Dr. John Martinez is a primary care sports medicine physician and medical director of Coastal Sports & Wellness Medical Center, a sports injury clinic in San Diego, CA. Visit us at http://tiensshop.co.uk/Muscle-Cramp-c2_15.html Find more articles like this at http://tiensshop.co.uk/Muscle-Cramp-c2_15.html Copyright 2008
==== ==== For more information on Muscle Cramp please check this out; http://tiensshop.co.uk/Muscle-Cramp-c2_15.html ==== ====
