Why did my legs lock up during a race?
March 9, 2019 1:24 PM   Subscribe

Yesterday I ran a half marathon. All went well until maybe the final 5 kilometers or so, when my legs sort of locked up and walking became necessary. Why did this happen? Details inside...

This was my fourth half marathon, so I'm not a stranger to running that distance. Beforehand, I was well hydrated, and during I sucked on candies and kept staying hydrated. My energy levels were good, basically, though at the end the leg issue and lack of energy kind of formed a double whammy. My breath was steady, though, even during the tough parts.

My legs, starting around the last 5k but especially through the final 2k, just started locking up. Not cramps per se, though I felt little twinges of cramps. This was something different, like my leg muscles were slowly turning to stone, especially my thigh muscles. So I walked for a minute or two or three then started jogging again. It would be fine for a while but eventually my legs would lock up again. I ended up walking a LOT more than normal, which was a disaster for my goal time (finished a full 15 minutes later).

I've been running seriously for about 5 years now and this is the first time that's happened to me, in a race, training, whenever. So I want to find out why.

Possible culprits:

--Last weekend, four days before the race, my family and I went on a short trip, and for three days we did a LOT of walking.

--The weather was in the high 50s and sunny, but windy. Sun was warm but the air was cold, especially in the shade. I wore a T-shirt and shorts. Never felt cold, but maybe I should have worn my leg tights?

--I wore some old shoes. They are good shoes but a few years old.

Any ideas? Thanks.
posted by zardoz to Health & Fitness (8 answers total)
 
Oh, another possible culprit: leading up to the race, say over the past two months, I didn't put in quite as much mileage in training as I had wanted. Typically I run about three times a week, longer runs of about 10-12k, alternating with shorter runs of about 5-6k. But often just one of each per week. This was less training I did than in previous years. My first half marathon I ran a half marathon to train!
posted by zardoz at 1:45 PM on March 9, 2019


I would hesitate to look for a silver bullet, the cause would be multifactorial.

1) You probably went out to hard
2) especially if you were undertraining, which I personally would feel those volumes were, if you were trying to run a race similar to previous efforts.
3) When you run tired, your form breaks down, doing this in old shoes puts more pressure on your body absolutely.
4) All this would have been compounded if the course was hilly etc.
5) Sometimes you just have an off day, slight levels of sickness etc.

But if I were you first and foremost I would be grabbing a new pair of shoes and making sure my training for the next half ideally has at least 3 runs a week, with at least two of them lasting for an hour, peaking at no less than 15km long runs, hopefully a bit more.

PS, the candies probably aren't necessary. Your body has more than enough glycogen to last you for two hours of exercise, the slower you are, the longer you can last.
posted by smoke at 2:03 PM on March 9, 2019 [1 favorite]


Old shoes can make a massive difference - think how many times you step on each of them, and how much weight you put through them each time (ie. your body weight). Over the distance of a half marathon, having less cushioning than you're used to can have a huge cumulative impact. As smoke says, add that to being somewhat undertrained and it's just a perfect storm of factors.

That and, sometimes running is just weird. Sometimes you have a bad one and there's no obvious reason why.
posted by penguin pie at 2:15 PM on March 9, 2019 [1 favorite]


I’d really look at your electrolyte management. If you’re hydrating a lot without also taking salts (mostly sodium and potassium), you can have big problems with electrolyte balance, especially after exertion. The twinges you felt as well as your leg muscles not working as they usually do are clues that you may have had electrolyte issues.
posted by quince at 4:35 PM on March 9, 2019 [3 favorites]


Thanks for the answers, everyone. I will pitch the old shoes. Quince I thought my electrolytes were ok. I sipped on sports jelly and drank (the equivalent of) Gatorade on the race, but maybe that wasn't enough? So many factors. I'm thinking the main things are the amusement park trip (3 days of walking and STANDING in line) and my relative lack of training. For the next one in autumn I will definitely train harder.
posted by zardoz at 12:32 AM on March 10, 2019


I think that in those temps, with the gatorade etc, unless you sweat like a mad bastard and have a very low salt diet, your electrolytes would have been okay. Whilst low electrolytes can certainly exacerbate cramping, what you're describing doesn't sound like cramping to me - it sounds like tired legs that also didn't have enough miles in em (also, I admit, I'm a bit bias, I think people tend to go a bit crazy with the gels and sports drinks etc, they are way less necessary than most realise. I have run 30km with little water and no nutrition. If your 'tank' is well stocked beforehand you don't need it. The average body is swimming in glycogen and salts from our modern diets. Marathons are a different story, of course).

I had a similar feeling to what you describe when I ran a half that finished with a long, steady hill, off training that didn't include any hills, and a starting pace that was just too fast for my fitness at the time. Also, seriously, don't underestimate fatigue from the amusement park, standing is hard work on the body!
posted by smoke at 3:21 AM on March 10, 2019 [4 favorites]


Just ran a half this morning and saw quite a few people walking towards the end so it's not uncommon. I wouldn't get rid of the old shoes if they're otherwise intact but just used them for slower training and then get some new ones to use mostly only for races or fast runs. The cushioning does compress a lot over time and I find old shoes make my legs noticeably sorer than newer ones, especially when pushing it.
Also, agreeing on the no need for nutrition - it was cool and windy today so I didn't drink anything and only had a couple of cereal bars for breakfast before hand. That way you don't need to worry about upset stomaches or electrolytes etc.
It sounds like you're more on the undertraining side than over - perhaps throw in some longer slow runs every few weeks to build up resilience and stamina? Trails / hills are also good for strength. Don't worry about overdoing it - I ran 17km slowly yesterday and I think helped keep everything limber for today
posted by JonB at 4:37 AM on March 10, 2019


Training - for a marathon, due to the distance, and recovery time, it's kind of accepted that even with intermediate training you won't regularly be running mararthon distances. However, for a half marathon the recovery after a mid-effort run instead of a race should be enough that one can train doing that distance, or potentially more. I think the undertraining was the likely the biggest factor, combined with going out a pace too fast for your current training/expectation level.

Hills? Smoke points out that hills can be a factor; especially downhills can trash your quads. If you're going out strog as you said, and burning through a downhill can trash your quads - and the only good way to not have this happen is to have practiced running hard downhill, and recently. I tend to do further distances than you more regularly, but one trail race that I died on one year I had taken off of running for about 5 weeks due to a minor calf injury at a previous race. I still kept up elliptical/bike, but had no direct stress. My quads were sheer pain on what was a relatively short and flat course to me, and similarly I had to walk the last ~30% of the course due to pain and my body not wanting to run.

Above was pointed out, electrolytes. For a half, one doesn't need to take in a whole lot (for days with weather between 0C-20C I've done training runs above 22K with no calories/water first thing in the morning on an empty stomach). So if you're taking in water and sugar, your salt levels could get pushed low. Gatorade is trash and doesn't have enough calories (nor the right calories) nor salt on it's own - compare it against something like Tailwind or Heed. Usually endurance athletes will directly take salt pills like s-caps or similar. Also, my experience at races is the gatorade is over-watered. Which is to say sure, it's better than water, but not by much. However, for the distance/time I think electrolytes were unlikely the issue.

shoes - do you track mileage? usually running shoes are "supposed" to last 500-800km. I've retired some shoes in the 600km range, but often go higher. I've never personally gotten beyond 1300km from any pair and not started getting more niggles during training than I thought was right. My experience has been lower leg issues when my shoes are breaking down, so these are the thing I think to be least likely to be the issue.

TLDR, I think your biggest issue was being undertrained combined with going out too fast for your level of training.
posted by nobeagle at 8:00 AM on March 11, 2019


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