Cramps have long been blamed on dehydration and sodium loss. But even after chugging bottles of water and electrolyte chews before your run, the familiar pain of a muscle cramp stabs at you not ten minutes into your run. Why? Conventional advice has said that staying hydrated and consuming enough electrolytes will prevent cramps induced by exercise. However, recent evidence points out that the contents of your water bottle are only half the battle. In fact, a study of 72 runners showed that there were no clinically significant differences in electrolyte concentration or hydration status between those who experienced cramps and those who did not [1]. This, along with other similar findings, suggest that cramps are not only from a lack of sodium or water. Instead, there has been rising scientific support for the nervous system’s role in communication between your nerves and muscles, known as the altered neuromuscular theory.
The altered neuromuscular theory associates cramping with muscles being exhausted, ultimately causing imbalanced signaling from your nerves [2]. The muscle has two types of proprioceptors, or sensory receptors that signal information to the brain and prevent yourself from damaging your muscles: muscle spindles and the Golgi tendon organs. When a muscle is stretched, the muscle spindle fibers also stretch and send signals to the spinal cord that initiate a reflexive contraction [3]. This contraction prevents overstretching and possible muscle tears and damage. In contrast, the Golgi tendon organs are inhibitory and trigger the autogenic inhibition reflex, which forces muscle relaxation during high tension. The Golgi tendon organs act as a safety mechanism by preventing the muscle from overexertion and thereby straining or injuring itself [4]. By maintaining a balance between muscle contraction and reaction, muscle function is optimized while simultaneously reducing the possibility of injury.
However, muscle fatigue has been shown to reduce the tension between the muscle and tendons, thereby unbalancing the muscle’s motor neuron signaling. The sensory nerves in the muscle spindles begin firing more rapidly, while the Golgi tendon organ’s signaling diminishes [5]. This justifies why cramps are more prevalent towards the end of runs or when sprinting due to muscles tiring and attempting to contract while it’s already shortened.
So why is this theory important? Since cramps are now correlated to muscle fatigue, slowly conditioning and gradually increasing the volume and intensity of training can help build muscle endurance and improve the muscle’s ability to handle stress and delay fatigue. It also supports one of the fastest treatments for an ongoing cramp: stretching [6]. Static stretching in particular helps increase the tension in the tendons, thereby reactivating the Golgi tendon organs. By encouraging relaxation, the process helps to mechanically reduce the current pain of the cramp. It also counteracts muscle shortening, making it harder for the cramp to quickly recur.
Ultimately, the cure for cramps is a lot less glamorous than a magical electrolyte packet and much more scientific. By understanding the process behind cramps and focusing on smart training and building endurance, you can stop choking down electrolytes while simultaneously reaching your running goals. Your muscles – and taste buds – will thank you.
Sources:
[1]: https://pubmed.ncbi.nlm.nih.gov/15273192/
[2]: https://www.physio-pedia.com/Exercise-Associated_Muscle_Cramps
[6]: https://pmc.ncbi.nlm.nih.gov/articles/PMC8775277/?utm_source=chatgpt.com#i1938-162X-57-1-5-b05