What Causes Cramps and How Do You Stop Them?

Many of us have experienced the all too common cramp that causes us to cease exercise immediately and try to walk it off. If you have not experienced it for yourself, you can probably view this occurrence around mile 20 of any marathon. Athletes moving along fine and then all of the sudden being reduced to a walk, and this is not just a symptom that affects amateur athletes. Cramping does not discriminate and can affect an athlete anytime, anywhere. 

There are a few different types of “cramps” that an athlete can experience during exercise or even racing event. While many immediately think of a muscle cramp in your quad, calf, etc; this also can be felt in your gut, or also as we may be familiar with – side stitches.

What causes muscle cramps during exercise and how can we avoid falling victim to them? This will be very individualized as each person will react differently / respond differently from one another. Understanding what is occurring during these periods of time can help you to determine your own plan of action and how to get rid of cramps.


Intestinal Cramping


Nearing the top of the list of gut issues athletes can encounter when training or racing is intestinal cramping. Exercise-Induced Gut Ischemia refers to a loss of blood flow to your gut, which occurs during exercise. Your body regulates blood flow to the working muscles and limits blood flow to the gut in order to achieve maximal muscle production. What does this mean for the gut? It has a harder time processing / digesting foods during exercise. Exercise-Induced Gut Ischemia, plus anything that inhibits or impedes blood flow to the gut, has the potential to cause gut issues. 

What causes this? Aside from dehydration, there are two common nutrition pitfalls that can cause this: consuming concentrated sports drinks and too many carbohydrates. This occurs due to a shift in your blood osmolality (a measure of the numbers of particles dissolved in a fluid, the greater the concentration of the substance dissolved, the higher the osmolality) which in turn makes your brain perceive this shift in your blood as cramping, discomfort, and pain.

What can you do for this? Try opting for a sports drink with approximately 4-8% carbohydrate. Another is to try consuming beverages that contain multiple sugar types like glucose and fructose. Your stomach has multiple transporters that can only handle so much at one time when it comes to sugars. If you overload any one of these transporters, this can result in incomplete absorption which leads to gut cramping!


NSAIDs


NSAIDs (non-steroidal anti-inflammatory drugs) such as naproxen, ibuprofen, and aspirin are other common culprits of cramping. NSAIDs are commonly consumed by many individuals for pain treatment, and this includes athletes. Side effects of these medications include abdominal cramping due to your intestinal tract performing at suboptimal levels. Why does this occur? “Leaky gut,” as the layperson may refer to, is really just intestinal permeability. When your intestines are performing at 100%, they act as a tight barrier that controls what enters your bloodstream. NSAIDs decrease this performance and can cause cracks or holes in the lining, which in turn can create inflammation, and changes the environment of your gut. If able, try avoiding high doses of NSAIDs if looking for ways to avoid gut cramping. 


Side Stitch


Another type of cramping athletes experience is, Exercise Related Transient Abdominal Pain (ETAP) also known more commonly as a side stitch. These types of cramps can affect any part of the torso, but historically the left/right sides of your torso are more typically experienced. These types of cramps are distinguished by localized sharp pains in the affected areas. Side stitches can happen to any athlete but are more commonly experienced in runners and swimmers where there is a higher frequency of “up and down” displacement. 

While the cause is not 100% definitive, one theory that has gained traction over the years is that these cramps are due to irritation of the cavity of the stomach lining being heightened due to physical movement. This lining encapsulates the entire stomach wall and can give a reason as to why you can have this intense pain all over (not just on your sides!)

What can you do to get rid of abdominal cramps? Much to athletes’ dismay, there is no real cure for this cramping outside of limiting hard exercise and letting symptoms subside. There have been several strategies hypothesized, but remain unproven.


Muscle Cramps (EAMC)


EAMC, which stands for Exercise-Associated Muscle Cramps, can affect athletes and non-athletes alike. These types of cramps are defined by painful involuntary skeletal muscle contractions. Most frequently, these types of cramps will occur in your body’s lower extremities, such as legs.

What causes muscle cramps during exercise or EAMC? The two driving theories are electrolyte imbalance in combination with dehydration, and muscular overload in conjunction with neuromuscular fatigue. Though both have been researched and studied, the conclusion appears to remain the same: there is no clear cause for muscular cramping.

The neuromuscular theory of EAMC proposes that muscle overload and neuromuscular fatigue cause an imbalance between excitatory impulses from muscle spindles and inhibitory impulses from Golgi tendon organs (GTOs)2 These GTO’s act as a safety mechanism for our muscles to sense the tension in our muscles. Localized EAMC tends to occur when the muscle is contracting in an already-shortened position.1 The reduced tension in the muscle-tendon likely reduces the inhibitory feedback from GTO afferents, thereby predisposing the muscle to cramp from the imbalance between inhibitory and excitatory drives to the alpha motor neuron.2

How to stop muscular leg cramps or any EAMC? In order to try and combat cramping, some strategies include mechanical remedies for athletes such as massage or stretching. Ensuring you get in a progressive warm-up before exercise to ease and warm your muscles up for work to be done, is helpful to fend off muscular cramping. That said, even the best-prepared athletes can still succumb to cramping even with proper warm-up and activation.

Beyond mechanical relief, the widespread belief is that dehydration and electrolyte imbalance are the root causes of exercise-associated muscle cramps. Most of this belief has been grown out of a few studies done and media marketing. This notion was born out of the hypothesis that there is a correlation between electrolyte imbalance and muscular cramping. The question then remained: if proper fluid and sodium balance were the cure, then why were athletes still experiencing cramping with proper nutrition intervention?

One beverage, in particular, has received a large amount of attention from the sodium intake belief: pickle juice. Despite the hype and hope for a cure, the studies to prove a correlation were few and far between. One piece of interesting information that has come from these studies is the following: vinegar is believed to activate receptors in the mouth and upper gut that quiet the neurons that send signals to your muscles.2 This discovery has led to additional research into foods that activate similar receptors. This category of food which includes: ginger, cinnamon, mustard, and chili peppers, is called TRP* vanilloids and ankyrins. *Transient Receptor Potential

While TRP vanilloids and ankyrins are not the end-all be-all answer to muscle cramps, they could potentially help next time you find yourself in a muscular cramp pickle. (Pun intended)


References:

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445088/
  2. Patrick Wilson, The Athlete’s Gut: Inside the Science of Digestion, Nutrition, and Stomach Distress (Boulder, CO: VeloPress, 2020), 151, 152)

Jeff Hoobler is an elite strength and endurance coach with over 30 years of experience coaching athletes of all levels, from beginners to world champions in a variety of sports. He has a degree in Sports Psychology and Exercise Science from the University of Kansas and is a Certified Strength and Conditioning Specialist through the National Strength and Conditioning Association. He is a USAC Cycling coach, MAT (Muscle Activation Techniques) therapist, professional bike fitter, and Foundations Training Instructor. In addition to coaching, Jeff is a competitive racer on the road, mountain bike, and cyclocross.

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