Muscle Cramps

Muscle cramps are a common complaint in athletes and general population alike.  Muscle cramps often occur during sport but can also occur at rest and commonly occur overnight while sleeping.  Although cramps are widely experienced their exact cause is still unknown.  There are two main hypotheses; the electrolyte depletion and dehydration hypothesis and the altered neuromuscular control hypothesis. Put simply muscles cramp because there is not enough electrolytes and water for proper muscle contraction to occur or the nerve signals that control muscle contraction are altered, for example, muscle fatigue.  There is not strong scientific evidence to support the electrolyte depletion and dehydration hypothesis, so the neuromuscular control hypothesis is the more likely cause.  That’s not to say that dehydration and electrolyte depletion does not contribute to muscle cramps just that the mechanism of the cramp itself is caused by altered neuromuscular control.  There is a lot of anecdotal evidence of cramps occurring more in hotter temperatures or in athletes who are dehydrated, but questions still remain if these are determining factors in muscle cramps.

To understand how altered neuromuscular control can cause muscle cramps we need to understand some basic physiology about muscle contractions.  Muscle contraction in skeletal muscle is controlled by voluntary nerve signals, meaning that in normal situations it takes a conscious thought to contract a muscle.  Fortunately this does not mean that we need to individually think about contracting every muscle when we want to move but that we have the ability to start and stop our movements voluntarily.  Compare this to visceral muscles (eg. the heart and intestines) these muscles contract involuntarily, meaning we do not need to think about keeping our heart beating or our intestines digesting our food.  There is also a range of nutrients and chemicals that play a role in muscle contraction which is why the electrolyte depletion and dehydration hypothesis remains a possible cause of muscle cramps.  The other factors in play are the proprioceptors that we find in muscles to prevent damage caused by over-stretch or over-tension.  These proprioceptors are called the muscle spindle (protection against over-stretch) and the golgi tendon organ (protection against over-tension).  These proprioceptors seem to be the likely cause of muscle cramps during muscle fatigue and the altered neuromuscular control hypothesis.

The big question is ‘What can we do to prevent muscle cramps from happening?’ and ‘What to do if you are having a cramp?’  There is a range of home remedies for treating and preventing cramps, most of which revolve around the electrolyte depletion and dehydration hypothesis.  Things like drink more water, eat a banana, take magnesium tablets or drink coconut water.  There is no solid scientific evidence to suggest that any of these methods actually prevent or treat muscle cramps.  Therefore, they can be used as a ‘if it works for you do it’ method as there is also no negative consequences of any of these methods.

The best option for treating a cramp is to stretch the effected muscle. This supports the altered neuromuscular control hypothesis as it is having an effect on the proprioceptors in the muscle.  If the most likely cause of muscle cramps is muscle fatigue the best prevention is muscle strengthening and conditioning.

If you have been experiencing muscle cramps and want to talk about strength and conditioning options book and appointment now.