Muscle cramps are one of the most perplexing problems endurance athletes face in training. I get several questions on what can be done about them every year. Here is such a question I just received.
I have recently purchased the Fast After 50 book and currently working through it and trying to come up with a training plan for an up and coming mountain race (running) > 4hrs in about 9 weeks. I have pretty good base fitness and have completed similar races already this season. I have one question. I suffer from cramps in long races, which I think is related to muscle fatigue, and basically I think the issue is that my race pace is much faster than the my long run pace I use in training. So the advice I have seen is that I need to train nearer my race pace. So would I make my long aerobic threshold run at a pace closer to my race pace? But if I do this will I lose the advantage of "teaching the body to use fat fuel" as part of my long run? So not too sure what to do but need come up with an approach to sort out the cramps.
Any feedback greatly appreciated.
Thanks for your note. Good question. I agree with your conclusion - it’s probably neuromuscular fatigue that triggers leg cramps. Recently a couple of new products have come to market that also agree with that assumption and may offer a solution. I really don’t know if they work or not. They are based on research in the last few years showing that the nervous system reaction that causes cramps can be interrupted by stimulating nerves in the mouth. That research was done using pickle juice. I don’t recall what all of the new products are called but one of them is explained here.
The question you pose about training is also a good one. I’d suggest you need both - aerobic threshold long runs (easy - zone 2 using my heart rate system) and also race intensity (or slightly greater) runs. The latter would be done as tempo intervals such as 5- to 20-minute work intervals at just above race intensity (preceded by a warm-up and followed by a cool down). In my pace zone system this would probably be zone 3 for your type of racing. The recoveries between intervals would be about 1/4th as long as the preceding work interval. As an ultra-runner you would probably need to gradually increase to about 40 minutes (possibly to 60 minutes depending on your capacity for training) of total work interval time in a workout and probably do this once weekly in the Build period starting about 12 weeks before the race. These should be done on a soft but firm surface such as a track or trail. And if you mostly tend to cramp on hills then these intervals would probably best be done climbing. This should stimulate greater endurance at race pace and may help prevent fatigue and therefore cramps. But then, some athletes are so prone to leg cramps that they experience them even when it great shape. I’m afraid we just don’t know a lot about them, unfortunately.