Why do we cramp while racing?

Majority of endurance athletes believe that cramping is caused by dehydration or a loss of electrolytes.  Yes it is true that the body can cramp because of the loss of electrolytes but if you read the research you will easily see that this is most likely not the cause of the type of cramping suffered by majority of endurance athletes while racing.  As for dehydration being the cause- it is not- and we will address that topic in a future blog regarding the dangers of dehydration and over hydration.

When you look at the research you will find two main theories of why athletes cramp during racing.  The most widely talked about is the loss of electrolytes (sodium, calcium, potassium), which has spurred a huge market for the selling of salt tablets and other electrolyte pills. The other theory is not as widely talked about because there is nothing that can be sold or used to correct the problem, and that is the theory of neuromuscular failure which simply means your brain/nervous system is fatigued.

To figure out what may be causing your cramps we need to look at the two theories to see which is most likely the cause of your cramp and then we can develop a plan to avoid cramping during the race.

Loss of Electrolytes

A problem with this theory is that as we sweat our body’s electrolyte concentration actually increases. As an athlete continues to sweat during an event the brain realizes that it needs to conserve the sodium and will reduce the amount it expels through sweat. So as the body continues to lose water but retain its sodium the concentration of electrolytes actually increases.

Another issue with this theory is that the loss of electrolytes would cause cramping to occur in muscles throughout the entire body and not just in an active muscle being used during the event. What we all have seen (or experienced) during a race is that the cramping usually occurs in a muscle that is being used at the moment (calf during the run).  This alone should lead us to believe that the cramping is not caused by a loss of electrolytes.

Neuromuscular Failure   

All muscles have sensors within them that help protect the muscles from being over stretched.  We have all experienced this at one time or another.  Think back to a time when someone may have grab your arm as you where walking by and you had that quick reaction to pull your arm back to you.  What happened was the muscles in your shoulder sensed that your arm was being stretched to far to fast so it contracted the muscles to protect the joint from getting dislocated.  We also have sensors that tell our body when a muscle is producing too much force when contracting.

These sensors work together to allow proper motion.  For example: when your foot hits the ground during the run the stretch sensors feel the muscles stretch and then inform the muscle to contract which protects the joints and create forward motion.  Once the foot leaves the ground the other sensors tell the body that the contraction is no longer needed and we can relax that muscle.

The brain and nervous system control all of these sensors and when that system gets fatigued it can send mixed signals, which in result tell the muscles to contract and never to relax. That my friend is what you call a cramp! And this always happens within a muscle that is being used at the current time: like the calf while running.

Neuromuscular failure is generally caused because you are pushing the body too hard. This is why we have a higher tendency to cramp while racing when we are giving an all out effort rather than during training when the intensity is usually limited based on the purpose of the workout.

Bottom Line

You must first figure out what type of cramping you are experiencing before you decide the solution. If you are suffering from full body cramping then you need to come up with a nutrition plan that will replenish your electrolytes during training/racing.  If you are suffering from cramping of the working muscle (legs during the run) then you simply need to ease up at the moment of the cramp and recover.

Work, Live, Train

Coach Hammond