Exercise-associated muscle cramping (EAMC) is defined as an involuntary, painful contraction of skeletal muscle during or immediately after exercise ( Schwellnus et al 2011). There is a high risk in endurance athletes. It is poorly understood, although common. The reasons for the cramping could be:
1. the result of muscle fatigue
2. the result of serum electrolyte imbalance- perhaps as a result of profuse sweating
4. altered neuromuscular control
Risk factors for cramping
• You have cramped before
• Performing exercise in hot and humid environment
• Performing exercise at a relatively higher intensity, or longer duration than you have trained. (Schwellnus et al 2010)
• Perhaps running on an injury, protecting that injury then overloading another muscles group, resulting in other muscles being overloaded.
The key to preventing exercise-associated muscle cramps is to reduce the risk of premature muscle fatigue. You can do this by:
• starting your race conservatively- do not rush out at the start. Run well within your capabilities. It is often said to try run a negative split. See how you feel in the first half of a race, and then if you have extra energy you can push toward the end of the race.
• Be aware of your environment. Perhaps having trained in cooler weather conditions may make you more at risk if your race day is warmer e.g. comrades 2014 was incredibly hot and had an increased incidence of muscle cramping in runners. Another example is for cyclists or triathletes who cycle into a headwind on race day, this could result in earlier fatigue.
• Assess how you have been in the lead up to the race, how has your training gone, how is stress at work or home, have you had enough sleep. Many things other than training can lead us to feel fatigued on race day, or lead you to have an adjusted race day strategy.
• Assess how you are physically on race day- have you been sick in lead up to the race.
• There is evidence to suggest that an oral re-hydration solution may delay exercise-associated muscle cramps, and make them less likely to cramp (Lau et al 2019). Perhaps use this as part of your strategy for a race day- before, during and after.
Take stock of how you are in the lead up to the race, and this may help you plan for race scenarios you plan A, B and C.
If you do start cramping then
1) Stop and stretch passively
2) Try drinking an oral re-hydration solution rather than water on its own.
There is never a one size fits all approach, chatting to a healthcare professional or coach, can help you pin down why perhaps you cramp while someone else doesn’t.
1. Lau WY, Kato H, Nosaka K. Water intake after dehydration makes muscles more susceptible to cramp but electrolytes reverse that effect BMJ Open Sport & Exercise Medicine 2019;5:e000478. doi: 10.1136/bmjsem-2018-000478
2. Schwellnus M, Collins M, Drew N. Risk factors associated with exercise associated muscle cramping (EAMC) – a prospective cohort study in ironman triathletes British Journal of Sports Medicine 2011;45:316.
3. Scwellnus M. Cause of exercise associated muscle cramps (EAMC)–altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med. 2009 Jun;43(6):401-8. doi: 10.1136/bjsm.2008.050401. Epub 2008 Nov 3.