Found on RunnersWorld.com and written by A.C. Shilton
A muscle cramp can stop you in your tracks–but with science on your side, you can fix it fast.
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 43ultramarathoners. 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 theorizes 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 percent 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 mile 20 of a marathon than, say, mile two of 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.
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 (check out this articlefor an explosive plyometric workout)—explosive exercises that may improve the endurance of the receptors that are thought to misfire and cause cramps.
Pace Properly: If you trained logging 10-minute miles and you start racing 8:45-minute miles, 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 20 miles, 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.