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Walk Breaks | Marathons | Training | Endurance | Injuries

Why am I cramping at mile 21 of a marathon?

Q: I've run the Chicago Marathon for two years, and for two years I began cramping just around mile 21. I ended up running and walking the final five miles. When I ran after the cramping started, my legs felt good until the cramping began again a few minutes later. I've tried taking lots of fluids before the race, and this year I pretty much drank at every aid station after six miles. I don't know what else to try, and the experience yesterday is making me think about maybe never doing one of these again. Any suggestions?

A: The most common reason for cramping at that point in the marathon is having a longest run of 23 miles or less, three weeks before the marathon.

Other factors are the following:
* running even a little too fast during the first 13 miles
* not taking walk breaks from the first mile
* starting the run dehydrated by eating a big meal the night before - particularly one with a lot of salt in it.

Why can't it get much below 3:55 for a marathon?

Q: First, I enjoyed the chance to meet and join your 4:00 pacing group on Sunday. I'm sold on your run/walk program and will continue to use it. I did not train for this marathon that way but I'm very happy you talked me into joining you pacing group!

I do have a question. I'm 6'4" and weigh 250 lbs. (When you are ready to add a chapter on Clydesdales, please contact me.) My most recent half marathon time was 1:43:28. I ran a 21:58 5K at the beginning of September. But I can't seem to get much below 3:55 for a marathon. My chip time at the MCM was 3:59:59.

I ran easily with the group for the first half, ran negative splits through mile 22 and felt confident, I struggled a little to mile 23, then just barely hung on to the finish and felt poorly. I suppose the heat got to me. How can I be better prepared for the last three miles in the future?

I ate every 2 miles starting at mile 10, took water at every stop, and Drank 'til I sloshed the day before.

A: At your weight, your marathon times are going to be slower than those projected on the prediction table. You will also suffer more, and slow more, from heat, humidity and hills. On the other hand, you will benefit more from walk breaks, and a more conservative pace in the marathon. Your biggest mistake, in my opinion, was increasing the pace in the second half. Had you waited until the 22 mile mark, you may have finished 5 minutes faster. Hindsight is wonderful, however.