Muscle cramping is something that nearly every single endurance athlete has dealt with at some point in their sporting journey. Cramping can be mild and bearable for some, but debilitating for others. Cramping can also unfairly afflict some athletes more than others. Cramping during a race can literally cause an athlete to withdraw from an event they have trained for and invested in for months or even years of their life. Cramping also does not discriminate as it affects everyone from complete beginners to the highest performing professionals.
Muscle cramping, however, is an often very misunderstood topic and one that is fraught with misinformation and touted “miracle cures” and “formulas” that are supposed to help athletes avoid muscle cramping during training and racing. Yet, if there is anything that the research literature has taught us over the years, it is that muscle cramping is without a doubt NOT caused by one single factor. Rather, muscle cramping can have many, many different potential causes depending on the athlete. Therefore, any product or person claiming that the secret they harness a “cure” for cramping is one to likely take caution in.
Yes, dehydration, loss of electrolytes, fatigue, heat, and other things factor into the etiology of cramping in an athlete. But it is much more complex than just these factors in isolation. Some athletes may cramp in certain scenarios when others don’t. Some athletes might think they cramp because of dehydration or at a big loss of electrolytes when in fact that is not the cause at all. With this topic being shrouded in so much mystery, misinformation, and snake oils promising a cure, let’s take a look at a very recently published 2022 evidence-based review paper by Miller and colleagues (1) to dissect muscle cramping during exercise in a bit more detail and to help us understand what is really happening and then how to address it.
What are some of the proposed theories/mechanisms behind muscle cramping?
Firstly, we need to discuss some of the most prominent theories underpinning exercise-associated muscle cramps (EAMCs for short used herein). There are three primary theories that have emerged over the decades related to the pathophysiology of EAMCs. These three theories are as follows:
Dehydration and Electrolyte Imbalance Theory
This is the oldest and perhaps better-known theory underpinning muscle cramping. This theory postulates that a loss of fluids and electrolytes during exercise causes an increase in chemicals in the muscle that excite nerve fibers as well as an increased pressure on motor neurons, both of which lead to an increased likelihood of a sustained involuntary muscle contraction (i.e., cramp). This theory over the years, however, has had some ‘holes’ poked into it, giving it less shaky scientific ground to stand upon by itself as the sole reason for causing EAMCs in athletes.
Altered Neuromuscular Control Theory
This theory emerged in 1997 and was updated in 2009 to reflect the notion that muscle fatigue, combined with other risk factors, alters the level of excitation and inhibition that the motor neurons are receiving, thereby increasing the chances of a cramp. However, this theory also developed some flaws in its reasoning over the years and did not have the evidence to back it up either as the sole cause of muscle cramping.
Multifactorial Theory of EAMCs
This is the most recent theory put forth and proposes that EAMCs are likely due to a multitude of factors, of which dehydration, electrolyte imbalances, and fatigue are some of them. Any factor that increases motor neuron activity and increases muscle cell membrane activity can, in theory, result in an increased risk of muscle cramping. However, there are many ways in which this ‘altered neuromuscular control’ could be reached, including things such as dehydration, electrolyte imbalances, muscular fatigue, heat stress, prior muscle injury/damage, and certain medications, supplements, or conditions that affect the central nervous system. To see how complex this theory is and to get a better sense of just what factors might play a role in EAMCs, see the figure below taken from the Miller and colleagues’ paper (1).
As an example to help illustrate this theory further, consider an athlete that cramps during the final 10k or a marathon. Sure, fatigue may play a role and so may hydration and electrolyte status. However, what if this athlete had prepared well for the event and had followed a hydration plan that worked well for them? There could be other factors at play unique to this athlete at that time, including any stress outside of training they are under, the effects of any medication they may be taking, the environment they are racing in, and more. This athlete, however, might have mistakenly been taught to believe that cramps are caused by dehydration and electrolyte imbalance. They may, consequentially, go astray down a path of searching for further hydration planning and refinement that won’t provide any useful answers to their problem.
Essentially, when looking to find the underlying cause of EAMCs, the goal is to look globally at the athlete as a whole, identify any risk factors they present that could underpin altered neuromuscular control, and then address them (as seen in the figure/image above). In theory, this should help reduce the risk of cramping, but there will never be zero risk of EAMCs occurring during training or racing.
What does the evidence actually say is linked to muscle cramping?
This third theory highlighted above seems to be the theory that holds the most evidence and support. But basically, researchers and clinicians still don’t know the exact cause of muscle cramping. We only have a theoretical best guess. So, first and foremost, understand that anyone who claims to know the cause of EAMCs and precisely what to do or take to prevent it is not being truthful or is misinformed. This is the first step in knowing how to understand muscle cramping. There is a lot that we do know, but it is not enough to make a definitive conclusion pointing precisely to the cause of cramps. After you understand a bit more about what underlies EAMCs from a physiological perspective, we can then begin to make changes to prevent them or treat them.
What are the best strategies to prevent muscle cramping from taking place?
This is what most endurance athletes are interested in as the goal is always to avoid cramping up during an important training session or race, not only because cramping can drastically affect performance, but because they are painful and unpleasant. From a prevention standpoint, however, there are many things to consider. Like I mentioned previously, if you do experience cramps as an athlete, the best way to begin addressing this issue is to take a step back and look at various factors and begin addressing them one-by-one. The last thing you want to do is get caught in a trap of believing cramping is caused by one thing and go down a rabbit hole of trying to prevent cramps by addressing only that one factor, when you might have multiple factors that need addressing. The possible factors to address are too many, so I will include an image below from the Miller and colleagues’ paper (1) that poses questions to ask yourself in order to better identify risk factors for you as an individual that can be addressed:
As you can see, there are many questions to consider that go way beyond simply addressing hydration and electrolyte intake like many folks believe they need to do in order to solve cramping issues. Yes, these factors could be the ones causing or contributing to cramps for you, but they may not, or they may be two of many other factors to consider when trying to resolve your cramping issues.
My suggestion is to start with the questions above and work with a qualified professional in the areas that you might need to address. For example, if you think that muscular fatigue or prior muscle injuries might be placing you at risk for cramps, work with a qualified Physical Therapist or Strength and Conditioning Professional to begin addressing these areas. If nutrition and hydration are potential issues, work with your Coach or a Registered Dietician to address these areas of concern. If a medical condition or a medication might be the cause, work with your Primary Care Physician to begin addressing these concerns. Maybe you are under a lot of stress outside of being an athlete and you feel that your mental health is an issue. Work with the appropriate mental healthcare provider to work on addressing this concern.
I understand that this will likely be frustrating for athletes that do suffer from regular cramping that impacts their ability to perform, but the underlying causes are likely complex, and so the solutions that help reduce your risk of cramping will likely be somewhat complex as you try and navigate various items that increase your risk of EAMCs. I really do wish it was as simple as “drink more fluids”, “take more magnesium during exercise”, or “do more strength training”, but the reality is that EAMCs are a complex topic with many things to consider.
So, if you are an athlete that regularly suffers from cramps and you would like to try and lessen the burden of these cramps on your performance, start by trying to identify the factors you have that place you at risk of experiencing cramps, then work with the right professional(s) to begin coming up with solutions. Over time, you will hopefully see improvements and a lessening of the occurrence of cramps.
Remember though, realistically nobody is ever immune to cramping, even those that have never experienced one before. There will always be a possibility of EAMCs, particularly during higher-intensity and longer-duration performances when you are pushing yourself to the limit as an athlete. Understand that the goal is to work on reducing the likelihood of cramps from occurring in the first place, but to also be prepared to deal with them should they occur. This is what we will discuss in the next section.
What are the best strategies to treat muscle cramping after it has taken place?
The treatment for muscle cramping really falls under two categories: 1) things that can be done yourself to help alleviate cramping, and 2) things that should be done under the supervision of a medical professional should cramping worsen or present with other signs/symptoms.
The fastest way of stopping or relieving a muscle cramp once it has begun is through stretching, which is usually the natural instinct of any athlete when they feel a cramp come on suddenly. However, if the cramping persists and becomes debilitating to performance, more treatment may be needed. If the cramping is severe enough, it may cause you to pull out of a race. Typically stopping exercise, stretching the muscles that cramped, and focusing on general rehydration, is the best way to get them to stop, and this is supported by the scientific literature (1).
However, if you were to experience cramping that continues and worsens over time even after stopping exercise, along with the development of other signs/symptoms of a serious medical condition (e.g., dizziness, nausea/vomiting, collapsing, dark urine, altered state of consciousness), this is where medical intervention becomes necessary. There are many things a medical professional might need to do in order to address this type of scenario, and this is beyond the scope of this paper. It is important, though, to know what to look for in case you do feel that medical intervention is warranted.
Muscle cramping, or EAMCs as they were referred to often herein, is a complex topic that is not fully understood. Unfortunately there is not a clear cause of muscle cramps nor a clear treatment approach for preventing muscle cramps. However, by taking a global and multifactorial approach to understanding yourself as an athlete better, you may begin to identify various risk factors of muscle cramps that you can address under the guidance of the appropriate professional. Cramping is something that is all too common in endurance sports, and so it is important for athletes and coaches to be well-informed of the current scientific literature surrounding EAMCs so that the proper recommendations are made to remedy muscle cramping in those that are trying to address it.
Miller KC, McDermott BP, Yeargin SW, Fiol A, Schwellnus MP. An Evidence-Based Review of the Pathophysiology, Treatment, and Prevention of Exercise-Associated Muscle Cramps. Journal of Athletic Training. 2022 Jan;57(1):5-15.
Happy training and racing!
-Ryan Eckert, MS, CSCS
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