Many of us have had the experience - your marathon is going well, you're on track to meet your goal. Then from out of nowhere, a leg cramp stops you dead on your tracks. Regardless how hard you try, it's impossible to resume running at your previous pace, bringing your race to a painful conclusion.
Leg cramps are commonplace. 39% of runners have experienced them. Surprisingly, there is no consensus among experts what causes cramps and how to prevent them.
Why? It's difficult for researchers to duplicate in a lab environment the exact race conditions where cramps are most likely to occur, like the latter stages of a marathon. Dehydration, sodium loss, muscle fatigue due to hours of pounding are all taking place simultaneously.
What causes cramps? The current thinking (but not a consensus) is that muscles spindles (sensory receptors within the belly of a muscle) become fatigued and misfire, causing an intense involuntary sustained muscle contraction.
The two most common theories on what causes this fatigue and misfire:
1) Dehydration and electrolyte loss
Although this explanation was commonly believed to be true, there was very little evidence to support it. In a 2011 South African study of 200 Ironmen, there was no correlation between reduction of body weight (an indicator of dehydration) or electrolyte loss and cramping.
Researchers concluded the only two factors correlated to cramping were a faster race time and a history of cramps in previous races.
By the way - there's no scientific proof that either bananas or salt can prevent or relieve cramps.
2) Muscle fatigue (compounded by dehydration)
Although there is not yet a consensus in the research community, this explanation is the leading contender. It make makes sense. Anecdotally, cramps are far more likely to happen after mile 18 (30K) of marathon or in latter stages of ultra, not at end of hard 5K, where muscles may be fatigued but dehydration is rarely an issue.
If you are prone to cramping, part of your training should focus on cramp prevention.
1) Practice running long, with workouts that simulate race conditions. One example would be:
A 6-7 mile (10-11 km) steady state run - The next day, run a 16-18 mile (26-28 km) progression run
You start your long run on legs that have not fully recovered from the previous day's run, and then practice speeding up and holding the pace as you physically and mentally fatigue.
2) Strengthen leg muscles with explosive exercises e.g. Plyometrics
Of course, race at a pace that is appropriate for your level of training.
Most importantly, be an experiment of one. Record the exact conditions when cramps occur. You may be able to isolate the exact cause of your cramps
If you get a cramp during race, stretching immediately has proven to be the most effect method to relieve cramps.
Strange but true: a study at the University of North Dakota concluded that drinking pickle juice was very effective in relieving cramps. And fast acting too; relief in less than 90 seconds.
How can this be? Drinking 2-3 ounces does not affect dehydration. 90 seconds is too fast for the juice to reach the blood stream and cramped muscle. One plausible explanation is the juice affects the nervous system, causing it to turn off the overactive spindles that are causing the cramp.
If you are prone to cramps, consider carrying 2-3 ounces in your fuel belt. But practice gulping the pickle juice during training. What do you have to lose?
Have you ever suffered leg cramps when racing? What strategies have you tried to prevent cramps or alleviate the pain?
© 2014 Savvy Runner Inc.
Bennett Cohen and Gail Gould are the Founders and Presidents of the International Association of Women Runners. For access to resources to help you reach your goals for running and racing, visit www.IAWR-Connect.com..
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