The last 3-4 times I have run half-marathon or similar distances, I have experienced the preliminary symptoms of cramps around the 19 km mark. It comes as a suddenly "bite" in the upper part of my calfs - it doesn't hurt all that much, but there are no doubt that is will if ignored... When the "bite" comes, I have to run more on my heels the rest of the race to avoid the "bite" develops into full-blown cramps - kind a like "running calf stretch" and not very comfortable.

The "bite" is usually first in the left leg, but after an additional 2-300 m, the "bite" is also present in the right leg. The faster the pace - e.g. during races - the earlier it will happen... If I stretch and walk for a few minutes when it happens and then start running again, the "bite" is sure to reappear again after 8-900 m...

Except for the night after one of these longer runs, I usually don't have cramps at night.

The accepted answer to Why do I get cramps all the time? sugests that it is a electrolyte imbalance and the problem is lack of salts like potassium, sodium, calcium, and/or magnesium. Lots of other articles - e.g. What are Cramps? How to prevent Cramps to mention one - sugest the same, so I can easily accept that.

But... what can I do about it? I really want to run these longer distances...

Are there anything specific I can eat or drink?

I usually eat lots of bananes (which contains potassium AFAIK), and have also consumed large amount of "Tonic Water" (which contains quinine), but neither of these seem to be enough.

Are there any specific gels (or whatever) that could help during the runs? Eating lots of bananes during a race, does not seem to help at all.

EDIT A little more background:

My average milage is 30-40 km/week - less in the Winter (now) and more in the Summer. I have run HM races 5 times in the last year and 17-24 km training passes 6-8 times in the same period. So, I should expect my general fitness as well as my LSR training to be OK.

The last training pass (a rather fast 18.8km yesterday) actually went pretty well - no bites - using a "MAXIM GEL Drink" at 8 km and plenty of Powerade at 5 km and 13 km. The training is part of Sparta Marathon Training leading up to Copenhagen Marathon in May. The training is a little short to be conclusive!!!

UPDATE (2012-01-28): I have begun to run longer during the week and - when that is not possible - use my bike to and from work. That has helped: I have not experienced any cramps since mid December. Thanks...

  • I would suspect that what you call a 'bite' is not a cramp in that case. But what? Dunno.
    – geoffc
    Dec 16, 2011 at 13:35
  • It feels very much like the very beginning of cramps. And I know, if I continue for just a few more meters without running on my heels, it will be cramps for sure... Dec 16, 2011 at 14:34

4 Answers 4


There are a number of reasons why you could be experiencing cramps at that distance, most likely is under-training, meaning that the body is not used to doing that amount of exercise and is trying to warn you of this. Solving this would involve you doing the race distance a few times as part of your training, at a more relaxed pace.

Another could be an electrolyte imbalance or lactic acid build-up, for the electrolyte imbalance you can take a good sports-drink, and I've found that antacid tablets work quite well for the lactic acid build-up, just suck a few of these during the event, no need to overdose.

Lastly, I've experienced "bites" during a race recently because my body was tensed up, happened around the 60km mark of a 200km race (cycling), after concentrating to relax, and staying at the back of the train for a while, the bites went away, and I finished the race without any more problems.

  • See my edit of the question above. Dec 19, 2011 at 9:07

40 km per week sounds like enough training miles to do a 1/2 marathon comfortably, but 30km doesn't.

Could this just be a case of not doing enough miles of training before the main event? Or alternatively you're running too many miles the week before? The general advice is to reduce the mileage to the short-run amount during the final week, and skip your final training session, replacing it as rest.

http://www.copenhagenmarathon.dk/traningsplan/ is showing a week between each training session. Is this correct? If so that is not the recommended* way of training for long distances. It should be atleast 3 sessions per week (short, medium, long), or 4 if you're going for PBs. The long run should eventually be around 11-12 miles in the final week before the race.

* Recommended being Runnersworld.com and this book

  • The problems with the "bite" have been present at least the last 6 months. Even when doing a lot more training than just 30-40 km/week. Also I usually have a taper before every event of 5-10 days with just very short and slow trips. The training runs provided via Sparta is just for the weekend - during the week, I try to run 1 or 2 short trips (5-8 km) and bike 90-120 km (to and from work). [This time of year, when it is dark and cold, this is the best I can do :-)] Dec 19, 2011 at 12:56
  • @Tonny ok, I wasn't sure if that was 3 runs in the beginning text or not, obviously what I've written isn't really relevant. Too many miles too quickly perhaps?
    – Chris S
    Dec 19, 2011 at 13:23
  • I hope not. That lead to a severe case of PF last year. No, this time it was a gradual increase over 5 months. Dec 19, 2011 at 14:00

I would be uncomfortable with drinking both lots of tonic water and taking tablets. I don't see the point of worrying about quinine and I would be worried that you are diluting your system too much - and therefore don't have enough salt concentration.

However, with the cramp happening at 19km or so I would be suspected undertraining more than electrolyte imbalance.


  • Do longer runs more often and do them closer to your race pace.
  • Increase your weekly mileage to more like 50km/week (30-40km is too low for half marathoning successfully)

I agree with you that your cramps are likely due to an electrolyte imbalance. Personally, I drink coconut water during long runs. It contains electrolytes, and is completely natural. You could also drink Gatorade, Powerade, or similar sports drink. I have never heard of tonic water being beneficial for running.

For runs longer than an hour, you may want to incorporate gels. I have heard good things about Honey Stinger gels, but have not used them myself. They have a toll-free number on their info page, which you can call to ask questions about product use.

I hope this helps. Good luck with your training.

  • There are several pages that mention Tonic Water - which contains smaller quantities of quinine - should be good against the cramps. E.g here: patient.co.uk/health/Cramps-in-the-Leg.htm Dec 21, 2011 at 15:58
  • @TonnyMadsen The page you linked says that quinine supplementation is a last resort and can have side effects. Instead, I would suggest using something natural like coconut water, or something designed for sports like a sports drink or gel.
    – LFurness
    Dec 21, 2011 at 16:03
  • I use sports drinks as well as gels during races and longer training runs. The Tonic Water can be considered a desperate attempt.. Ohh, and I have to add here, that I really like the stuff :-) Dec 22, 2011 at 7:24

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