Here’s a question we received about cramping from a MTA Podcast listener named Angie from Ontario. We featured this on our September 22nd episode.
“This past weekend, I ran my third marathon and was very disappointed to have, again, debilitating cramps occur in my calves, but unfortunately this time it occurred much earlier in the race, around the 18-kilometer mark, and I struggled with a walk-jog the rest of the way.
The difference is this time I had consumed quite a bit of electrolytes in the days leading up, in addition to purchasing a vest and actually had electrolytes that I carried with me that I took every 20 minutes or so, as well as I used the electrolytes that were available on the course.
So my question to you is, if it’s not an electrolyte imbalance, what else could possibly be causing my leg cramping, especially in the calf muscles? Thanks so much.
Coach Angie’s Reply
While cramping can certainly be caused by dehydration and low electrolytes, research has found that most causes of cramping during marathons is caused by neuromuscular fatigue and muscle overloading.
Here’s what happens: sustained running can overwork your muscles and inhibit the nervous system from communicating smoothly with those muscles. The nervous system signals the muscles (usually in the lower body) to contract but the signal for them to relax is suppressed resulting in muscle cramping and spasms.
There are a few things that play into the signaling errors including pacing (starting too fast in the first half), muscle overload from weak hip and glute muscles which puts more strain on the quads and calves, inadequate training (too much too soon), and to a lessor degree electrolyte imbalances. From my experience as a coach, master’s runners are more prone to cramping.
There is no method to completely guarantee that you won’t deal with cramping but there are some things that you can do in training and on race day to help prevent them.
1. Build a solid running base– this allows your muscles and nervous system to adapt over time. Do some marathon paced training so that your body is used to sustaining the pace that you’ll be running on race day.
2. Strength train on a weekly basis, especially focusing on hip, glute, and calf strength. Try to do at least 2-3 strength sessions a week. Specific exercises that help include weighted lunges, squats, hip thrusts, and loaded calf raises.
3. Stretch out your calf muscles after every run and consider trying compression socks or calf sleeves to help with blood flow.
4. Taper well before your race. Make sure you show up to the starting line with well rested legs.
5. Pace yourself conservatively during the first half of your marathon. This will reduce the chance of neuromuscular fatigue setting in early. It will also help you maintain better running form throughout your race.
6. Follow your fueling, hydration, and electrolyte plan.
7. If you start getting a cramp, slow to a walk, and try to stretch out the cramping muscle. In the case of the calves, dorsiflex your foot (bring it up toward your shin) to lengthen the calf muscle. Stretch for 60-90 seconds and start walking again if it has improved. If all seems good with the walk, start to run again at a slow pace.
If this keeps happening at the same distance despite strength and conservative pacing, it’s worth a gait look or a sports-med check for a true imbalance — but for most marathoners in your situation, the calf is tired and under-supported, not just dealing with a lack of electrolytes.
Go deeper! Here’s a guest post from Dr. Ben Shatto on 12 Strategies to Prevent and Self-Treat Muscle Cramping.
