Why they might occur and how to try and prevent them.
Exercise Associated Muscle Cramps (EAMC) are a common occurrence in most aerobic (longer distance) and anaerobic (short distance) recreational sports. In a squash game last week, my opponent went down with a cramp in the fifth game. The question begs, what should he have done next and what could he have done to prevent it? To breakdown the myths and falsies of muscle cramps I did a search through the UBC library. I was able to find some useful information which is provided below.
- Sports related cramps are not particularly damaging and can often be treated easily and quickly.
- Cramps in hot-humid climates may be caused by dehydration-electrolyte imbalance, but the evidence supporting this theory is weak.
- The neuromuscular theory proposes that when the muscle is overloaded neuromuscular fatigue sets in, causing an imbalance between the excitatory and inhibitory impulses. This theory also has limitations, but it is the most favored theory at this time.
- The most likely cause for EAMC is a combination of the above dehydration-electrolyte and neuromuscular fatigue theories. Depending on the environment and the type of sport, one or the other may play a larger role.
- Slow walking, slow muscle pumping, and slow controlled stretching in the opposite direction to the cramp. Most likely all the things we would naturally do!
- Ensure adequate hydration prior to and during exercise. Low level carbohydrate drinks (6-7%) are best taken prior to and every 15-20 minutes of exercise. This is particularly true in hot-humid environments.
- Prevention of neuromuscular fatigue. Adequate training of the neuromuscular system through specific plyometric training may have a beneficial effect. (a video post on good squash plyometric exercises will be up next week)
- Endurance (long distance) training to increase plasma volume and expand the extracellular fluid compartment.
Schwellnus MP. Cause of Exercise Associated Muscle Cramps (EAMC) — altered neuromuscular control, dehydration or electrolyte depletion? British Journal of Sports Medicine 2009;43:401-408.
Mayo Clinic. Muscle Cramps. Retrieved on May 31, 2013 from: http://www.mayoclinic.com/health/muscle-cramp/DS00311/DSECTION=risk-factors
Miller KC et al. Exercise-Associated Muscle Cramps: Causes, Treatment, and Prevention. Sports Health: A Multidisciplinary Approach 2010;2:279.