Muscle Cramping in Athletes—Risk Factors, Clinical Assessment, and Management
Section snippets
Definition and classification of EAMC in athletes
Muscle cramping can occur as part of the general symptom complex of a variety of medical conditions. Medical conditions and abnormalities where muscle cramping can occur have recently been reviewed (Table 1) [13]. It is not within the scope of this article to discuss all these medical conditions. Therefore, this article focuses solely on exercise associated muscle cramping. EAMC excludes cramps that occur in smooth muscle, cramping that occurs in skeletal muscle at rest, and muscle cramping
Epidemiology of EAMC
Prevalence can be defined as the “overall proportion of a population who suffer from a disease” [18]. The lifetime prevalence of EAMC can thus be defined as the number of athletes who have experienced EAMC at some time in their athletic career. The lifetime prevalence of EAMC in different sports has not been well documented; however, the lifetime prevalence of EAMC in sports where this has been reported is presented in Table 2. These data show that EAMC is common in sport, and it appears that
Etiology of EAMC
The more traditional hypotheses for the etiology of EAMC are the role of systemic electrolyte abnormalities, hydration status, metabolic abnormalities, and environmental factors (often termed “heat” cramps); the scientific evidence supporting these hypotheses has recently been reviewed [19]. The scientific evidence for these hypotheses rests largely on anecdotal observations, isolated case studies [11], [20], [21], [22], and a few small case series [10]. In contrast, data from four prospective
Risk factors associated with the development of EAMC in athletes
Although the exact etiology of EAMC is still unclear, a number of studies have reported possible risk factors that may be associated with the development of EAMC. Scientific evidence to support each of these risk factors varies considerably. In Table 3, postulated intrinsic and extrinsic risk factors for EAMC are listed. In addition, the evidence from studies to support each risk factor is listed. The evidence is depicted as ranging from Level I (strong evidence), to Level IV (very weak or no
Clinical presentation of EAMC in athletes
Muscle cramping in athletes has a typical clinical presentation and the diagnosis is made based on a typical history together with findings on clinical examination. Rarely, special investigations are required to exclude other possible causes. A typical clinical history of an athlete suffering from EAMC will include the following:
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EAMC is more likely to occur when intense prolonged exercise is performed in a competitive environment under hot and humid environmental conditions [6], [29], [31]
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Onset
Management of acute EAMC in athletes
The immediate treatment for acute EAMC is to stop the exercise activity (rest) and to admit the athlete to a suitable medical care facility for full assessment, diagnosis and management. Once the diagnosis of EAMC has been established, the most effective immediate treatment is passive stretching of the affected muscle groups [32], [33], [34], [35], [36]. Passive stretching increases the tension in a muscle, thereby increasing the Golgi tendon organ's inhibitory activity [24]. The effectiveness
Diagnostic approach to the athlete presenting with recurrent EAMC
The clinician is often faced with the problem of the athlete who presents with a history of regular episodes of EAMC. In these athletes it is very important to identify whether the athlete suffers from EAMC, or whether the cramping is related to an underlying medical condition (see Table 2).
The first step in this assessment is to take a careful, comprehensive medical history. The history is the key to distinguishing EAMC from other disorders that cause cramping. The following questions are
Prevention of muscle cramping in athletes
The key to the prevention of acute EAMC is to protect the muscle from developing premature fatigue during exercise. The following general guidelines are recommended:
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Awareness that EAMC is more likely if premature muscle fatigue develops
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Awareness that EAMC is more common in hot and humid environmental conditions
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Athletes should perform their activity at a lower intensity and a shorter duration if they are prone to EAMC
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Athletes should be well conditioned for the activity
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Athletes should perform
Summary
There is a high lifetime prevalence of EAMC in athletes, specifically in endurance athletes. There are a number of traditional hypotheses for the development of EAMC in athletes, including electrolyte disturbances, dehydration, extreme environments, and inherited metabolic abnormalities. However, a careful analysis of the existing scientific data, including data from recently published prospective studies, does not support the hypotheses that EAMC is caused by serum electrolyte disturbances or
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