Marathons and Muscle Cramps

Jannine Myers

In past marathons that I have run, I've experienced severe muscle cramping during the final few miles. The cramping has always been on one side of my leg, and has either affected my lower leg muscles, or my hamstring and/or IT band. I used to think that my cramping must have been due to electrolyte depletion, and with each new race, I would take extra care to ensure that I had a good fueling strategy in place. But, despite my efforts, I continued to be plagued by muscle cramps that forced me to drastically reduce my pace and of course, cause disappointment.

In pain after the Okinawa Marathon - hamstring and IT band cramp started around mile 21

In an article I read recently, I was surprised to discover that there may actually be another cause for my muscle cramps. The article cited literature published by the American College of Sports Medicine (Bergeron, 2008), in which the author suggested that another cause of muscle cramping, besides that of electrolyte depletion, is "skeletal muscle overload and fatigue."

This type of cramping is unfortunately, not easily remedied. In fact, it is often so severe, that even if an athlete is just a few miles out from the finish line and on target to achieve their race goal, it's highly unlikely that they will do so. The reason for this, is that the neuromuscular system, due to overload, essentially stops doing it's job and the affected muscles stop contracting the way they should. In this instance, there is little an athlete can do to reverse the cramping, except to cease all activity, or literally walk, hobble, or slow run (in pain) to the finish line.

A further point of interest regarding this type of muscle cramping is that only the muscles that are specifically fatigued are affected. Muscle cramping caused by electrolyte loss often results in the athlete feeling an overall sense of muscle cramping. And unlike the athlete who has fatigue-related muscle cramps, a dehydrated athlete with muscle cramps can often continue to run by stopping to re-hydrate (with an electrolyte drink), as well as stretch out the opposite muscles to cause a contraction in the pulled muscles.

So what makes me, and other runners, more susceptible to experiencing fatigue-related muscle cramps during the last miles of a marathon? Supposedly, such factors as:

• older age
• poor stretching habits
• insufficient conditioning
• cramping history
• excessive exercise intensity and duration
• metabolic disturbances

Note: these factors are different from those which are related to the type of muscle cramping caused by electrolyte loss. 

As I look at the factors above, I wonder if, apart from improving my stretching habits and ensuring that I train properly for each marathon, the onset of muscle cramps might just be inevitable for me, especially once I reach a certain level of exercise intensity and duration. And maybe that's the case for some of you too. 

While I'd like this to be one of those posts where I could easily leave you with some practical tips and advice, I'm not so sure I can. But I don't want to leave you feeling completely discouraged - let me add that not all of my marathon races have ended terribly for me. And, being hopefully optimistic, I still think that one day, I'll put my finger on that "magic" component of training and fueling that may directly determine whether or not I'll make it to the finish line free of cramps. When I do, you can be sure I'll share the secret with you.