Muscle Cramping in Athletes—Risk Factors, Clinical Assessment, and Management

https://doi.org/10.1016/j.csm.2007.09.006Get rights and content

Exercise associated muscle cramping (EAMC) is defined as a painful, spasmodic, and involuntary contraction of skeletal muscle that occurs during or immediately after exercise. There is a high lifetime prevalence of EAMC in athletes, specifically in endurance athletes. The most important risk factors for EAMC in athletes are a previous history of EAMC, and performing exercise at a higher relative exercise intensity or duration, when compared with normal training and participating in hot and humid environmental conditions. The diagnosis of EAMC is made clinically, and the most effective immediate management of EAMC is rest and passive stretching. The key to the prevention of EAMC is to reduce the risk of developing premature muscle fatigue.

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:

  • 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]

  • 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:

  • Awareness that EAMC is more likely if premature muscle fatigue develops

  • Awareness that EAMC is more common in hot and humid environmental conditions

  • Athletes should perform their activity at a lower intensity and a shorter duration if they are prone to EAMC

  • Athletes should be well conditioned for the activity

  • 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

References (40)

  • J.R. Stofan et al.

    Sweat and sodium losses in NCAA football players: a precursor to heat cramps?

    Int J Sport Nutr Exerc Metab

    (2005)
  • R. Tindall

    A survey of Exercise Associated Muscle Cramps (EAMC) in rugby players. BSc (Med) (Hons) dissertation

    (2001)
  • M.F. Bergeron

    Heat cramps during tennis: a case report

    Int J Sport Nutr

    (1996)
  • C. Grundling

    Die voorkoms van spierkrampe in fietsryers. MPrax Med dissertation

    (1994)
  • L. Parisi et al.

    Muscular cramps: proposals for a new classification

    Acta Neurol Scand

    (2003)
  • A.P. Jung et al.

    Influence of hydration and electrolyte supplementation on incidence and time to onset of exercise-associated muscle cramps

    J Athl Train

    (2005)
  • N.U. Sulzer et al.

    Serum electrolytes in Ironman triathletes with exercise-associated muscle cramping

    Med Sci Sports Exerc

    (2005)
  • M.P. Schwellnus et al.

    Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners

    Br J Sports Med

    (2004)
  • M.P. Schwellnus et al.

    Aetiology of skeletal muscle 'cramps' during exercise: a novel hypothesis

    J Sports Sci

    (1997)
  • T. Greenhalgh

    How to read a paper. The basics of evidence based medicine

    (1997)
  • Cited by (31)

    • Muscle cramps: A comparison of the two-leading hypothesis

      2018, Journal of Electromyography and Kinesiology
      Citation Excerpt :

      Nowadays, the scientific literature on this matter is supported by few systematic reviews. Schwellnus and Minetto, the two major experts on muscle cramps, reviewed this topic (Minetto et al., 2013; Schwellnus, 2009, 1999, Schwellnus et al., 2008, 1997). However, the focuses of these review articles were primarily centered on the latest scientific novelties and the neuromuscular hypothesis, respectively.

    • Exercise associated muscle cramps: Discussion on causes, prevention and treatment

      2014, Science and Sports
      Citation Excerpt :

      Among these 50 articles, 20 were literature review including 3 systematic review (with homogeneity) of randomized controlled trials (RCTs) (level of evidence [LoE]: 1) [17–19], 1 systematic review of prospective studies (LoE: 2) [20], and 16 narrative review (LoE: 5) [1,2,11–14,21–31], and 30 were original studies including 7 prospective studies (LoE: 2) [4–6,9,32–34], 10 case-control studies (LoE: 3) [10,35–43], and 13 case reports/series (LoE: 4) [7,8,44–54]. Among these 50 articles, 27 articles deal with EAMC [1,4–10,21–27,32–36,38,39,50–54], 7 articles deal with electrically induced muscle cramps [40–47], 7 deal with “heat cramps” [28–31,37,48,49], and 9 deal with muscle cramps without clear diagnosis [2,11–14,17–20]. Numerous theories for the aetiology of EAMC have been proposed: “serum electrolyte and dehydration theory” based on hypothesis of imbalance in fluid and electrolyte induced by sweat during exercise, “metabolic abnormalities theory” based on the description of muscle cell abnormalities in subjects with cramps, “environmental theory” based on case reports of muscle cramps occurring during exercises in extreme environmental conditions, and “altered neuromuscular control theory” based on hypothesis of the role of muscle fatigue in the EAMC development [1,26].

    View all citing articles on Scopus
    View full text