Dr. Kaleb Redden is a sports medicine physician, Titan Games competitor and Kaged Muscle team athlete.
Cramps are your body’s version of holding a protest sign that state they’re unwilling to work under such poor conditions anymore. However, while they may feel like a phone is vibrating within your muscles, exercise associated muscle cramps (EAMC) are quite common and can actually be very painful. Unfortunately, the underlying cause is often idiopathic or unknown, so we can put people on the moon, but cramps confound us. Before you lose faith, there are a number of secondary causes, including structural disorders, neurological disorders, metabolic disorders and some medications, but cramps from these causes are less common. If you were to ask the average person about the cause of a muscle cramp, you might hear something like, “You have low potassium. Just eat a banana.” Although electrolytes may play a role, potassium is not the smoking gun. Hopefully, after reading the following, you will have a better understanding of what a muscle cramp actually is and have a game plan for relief if you are unlucky enough to suffer one.
In the general population, it is estimated that nearly 50% of people over the age of 50 experience muscle cramping regularly, and that number increases with age. Muscle cramps are unbiased and affect both men and women equally. In kids, they occur in about 7% of adolescents with a peak occurrence between 16-18. In ultra distance athletes, like folks competing in Iron Man competitions, and the general athletic population, muscle cramps account for 6-25% of the most common medical complaints during competition. So not everyone will suffer regularly but pretty much everyone will experience a cramp at some point in their life.
Peeling Back The Skin
An EAMC might seem as though someone has a voodoo doll of you in their closet and the overall feeling of a cramp has been described as a sudden, painful, involuntary contraction of skeletal muscle, occurring during exercise or after, and is often noted as a visible knot or bulge in the muscle belly, lasting for seconds to minutes. The most common areas affected are the gastrocnemius (calf), the quadriceps (thigh) and the hamstring (back of thigh), but pretty much any skeletal muscle is susceptible. It is not uncommon to have cramps in the rectus abdominis (abs), gluteus maximus (buttock), hands or feet. A muscle cramp causes electrophysiologic changes, including increased frequency of muscle action potentials (contractions), increased neuron activity (nervous system excitement), and the depletion of muscle ATP (energy source for muscle contraction), which then causes accumulation of calcium, preventing muscle relaxation. There is repetitive firing of motor unit action potentials at a much higher rate than normal and there is a gradual increase of motor units recruited during the muscle cramp. This basically boils down to the muscle cells firing more often and faster than they should be and a subsequent build-up of by-products from the contraction blocking the release of the muscle.
The most likely answer is that it is not due to low potassium. There have been countless studies proving that people who have muscle cramps have normal serum levels of potassium. There have been a number of recent studies with ultra-distance athletes including Iron Man tri-athletes showing no association with decreased serum electrolyte concentrations of sodium or potassium and EAMC. That said, if a person does have electrolyte imbalances beyond the normal reference range, for example a potassium level greater than 5.1mEq/L or less than 3.4mEq/L, there is absolutely evidence of muscle contraction abnormalities. People who have those lab abnormalities often have a myriad of other significant symptoms well before muscle cramping.
In actuality, studies have shown the most likely cause of EAMC is muscle fatigue or overuse, based on the altered neuromuscular control theory. Without delving too deeply into neurophysiology, this means a muscle is overloaded or fatigued, causing an imbalance of the excitatory drive from the muscle cells to the inhibitory drive of the Golgi Tendon Organ (GTO). The GTO acts like the brake pedal in your car to stop muscle contraction, which is what saves you from tearing tendons under heavy load. The result of the GTO being inhibited is increased excitatory drive to the motor neurons producing prolonged muscle contraction. Cramps also occur most often when the muscle is contracted in a shortened position, which is significant because that also depresses the signal to the GTO. For instance, when you lie down in bed and your feet relax, the calf muscle shortens, this disengages the GTO, and the over-excited nervous system locks the muscle up. The result? A feeling like there is a vice grip squeezing your leg!
Cramp Risk Factors
Exercise intensity and duration (most significant)
Having a previous or current injury
Participant fitness level
Acclimatization to exercise demand
Weak muscle under high demand causing stronger antagonistic muscles to over-compensate
Lower Your Risks
To reduce your risk of EAMC, you should formulate a workout program that gradually increases in intensity. It’s important for the muscles to acclimatize to the demand you’re placing on them, after which you can then increase the demand to increase performance. If you are injured, take the time to go see your doctor and build a recovery program. Overall, it’s wise to make sure your physical fitness level matches the activity, sports or training regime you have decided upon. If you have muscle imbalance, focus on making weak things strong. For example, if you are a runner and have weak gluteus muscles, your hamstrings may pick up some of the slack. In doing so, the hamstring will then be overly fatigued and at risk of cramps. If you’re following along with Kris Gethin during his Man of Iron trainer, you will notice he trains his core much more frequently. Not because he needs a better six pack, but because his core fatigues on his long runs and he sure as hell isn’t going to stop running, so his back and legs suffer. Equalizing the load with a strong core keeps him balanced.
Cramps are a mystery and while the cause and physiology of an exercise associated muscle cramp may be confusing, the treatment is actually straight forward. The answer is stretching the muscle. Cramps generally occur in a muscle that is spanning two joints and acutely stretching the shortened muscle relieves the cramp. Stretching before or after exercise doesn’t seem to link with decreasing cramps but stretching right when it happens relieves the pain by activating the Golgi Tendon Organ, resulting in a reflex inhibition to the alpha motor neuron, causing relaxation of the muscle. So, the next time you are in bed and your calf muscle starts cramping, get out and stretch it ASAP. That is, if you aren’t so crippled from the pain that you can’t get out of bed. There are a dozen crazy things that have actually been studied in correlation to EAMC relief, such as pickle juice consumption, hyperventilation, salt tablets, etc. The sad truth of the matter is, there is no evidence that suggests these techniques reduce or relieve cramping.
Get Serious About Cramps
Remember, there are secondary causes of muscle cramps that are serious and should be evaluated by your physician. If you are having cramps that are not relieved by stretching or are occurring during times when you are not exercising, that’s a warning sign you should not overlook. In general, muscle cramps are benign, and the best way to treat them is acute stretching of the affected muscle. To best defend against them, be well acclimatized to the demands of your sport or workout, monitor fatigue level, and draw the line in the sand when enough is enough – stop. A great example of this strategy is our own Kris Gethin, a bodybuilder, now competing in Iron distance triathlon. Kris didn’t just start running, swimming, and biking those insane distances on day one of his training, but he gradually pushed his limits every day and allowed his body to respond and improve. It’s important to have the right coach, or trainer, who understands the limits of the human body and how to push them.