A muscle cramp can stop you in your tracks – but with science on your side, you can fix it fast.
Your Facebook post about a mid-race muscle cramp now has 32 unsolicited comments: Eat bananas! Salt tablets! Mustard! While the peanut gallery means well, the advice they’re dishing out may just be nuts. In fact, even experts can’t say with certainty what causes exercised-induced muscle cramps.
“Scientists have theories, but it’s hard to do research on cramps because they’re unpredictable and spontaneous,” says Kevin C. Miller, Ph.D., an associate professor of athletic training at Central Michigan University and devoted cramp researcher. In fact, one of Miller’s early career tasks was to devise a humane way to induce cramps. (The process he came up with involves electro currents and students’ big toes. He swears it’s not too painful.)
But even in a lab, multiple variables can be at play when a cramp occurs. “When I exercise, I lose sodium, I become dehydrated and I become fatigued,” Miller says. “The problem is all those things are happening at the same time, which makes it difficult to say definitively what’s responsible.”
What experts do know is that many common treatments have been proven ineffective. Which means it’s time to rethink your treatment regimen.
Cramp Culprits
Experts weigh in on two common theories.
Dehydration and Electrolyte Loss: The best-known theory is also the one with the least amount of scientific support. Timothy Noakes, M.D., Ph.D., D.Sc., a renowned exercise scientist from the University of Cape Town, calls the studies that link cramps to sodium loss and dehydration “bogus science.” In 2004, he studied the electrolyte levels of 43 ultramarathoners. Blood tests after a race showed no significant differences in blood sodium or magnesium concentrations between those who had and hadn’t cramped.
There were also no differences in body weight, plasma volume or blood volume between the two groups, showing that dehydration had no real effect. Miller agrees: If dehydration alone could cause a muscle cramp, he theorises that you could seize up in saunas or hot tubs, or even just walking around on hot days.
Muscle Fatigue: Dehydration, however, could expedite muscle fatigue, and that is what Miller believes is a likely cause of cramps. In that ultramarathoner study, 100 per cent of the runners who cramped did so in either the last half of or right after the race. Anecdotally, this theory holds up: Most people who cramp seem to be covering longer distances; cramps seem more common at the 32nd kilometre of a marathon than, say, three kilometres into a 5K.
Additionally, speedier runners seem to be at higher risk. Two 2011 studies found that fast-paced ultramarathoners and triathletes had more cramps than their slower counterparts.
Preventive Steps
Here are the best strategies for avoiding spasms.
Run Long: Guarding against muscle fatigue is key, so don’t take any shortcuts in training. “Train more, do longer distances,” says Dr. Noakes, a former ultramarathoner. “You have to adapt to the distance you want to race.”
Strength Train: Miller recommends plyometrics – explosive exercises that may improve the endurance of the receptors that are thought to misfire and cause cramps.
Pace Properly: If you trained logging 6-minute KMs and you start racing 4:45-minute KMs, your muscles won’t be prepared for that effort, and you’ll risk cramping, Miller says.
Keep Track: Miller thinks cramps are often caused by the perfect confluence of factors. “If you tend to cramp up at 32km, write that down,” he says. “Then write down the conditions: Was it hot? Was it humid? How much did you drink? What was your nutrition like the night before? Were you acclimated to the heat?” Track patterns over time, and you may be able to figure out exactly what makes you cramp.
