@molgrips

I get occasional cramp in the arch of my left foot, never the right, I have to concentrate and wiggle my toes to make it go away.

@skydragon

Work out your maximum heart rate(MHR) and your resting heart rate(RHR_. subtract RHR from MHR to find your working heart range (WHR). Whenever you see a percentage given as a target you add that percentage of your WHR to your RHR. So if your target range is 60%-70% and your RHR is 60 and your MHR is 180 you have a WHR of 120 and the figures are:

60 + (.6 x 120) = 132
60 + (.7 x 120) = 144

Note that 70% is usually taken as being close to your aerobic threshold, i.e. it’s the level you can, in theory, maintain for a period of time. However you might want to try the next zone down, that is 50%-60%. It will seem very easy and you’ll be tempted to push it especially if you are in a group so if you are zone riding it’s best to do it alone and somewhere flat.

Interesting article in training peaks on cramp – http://home.trainingpeaks.com/blog/article/the-real-cause-of-muscle-cramps

@molgrips, I’m not prone to cramp but if I do get it, it’ll be inner thigh too. Always thought it seemed an odd place for a cyclist to get cramp – get it a few times a year, usually in hilly races when I’m not used to racing ie start of the season or after a break from racing. However got a very similar sensation to cramp racing two weeks ago, turns out it was a slight strain due to my saddle height being too low but felt like cramp when it happened (standing up to sprint out of a corner for the 1000th time).

Another +1 for checking how much magnesium/electrolytes you’re getting. I was getting horrendous leg/foot cramps after around 2 hours riding, even with electrolyte drinks/ gels. Turns out it was low magnesium (found because I also started getting chronic migraines), the drinks & gels just simply didnt replenish what I was using.

I do occasionally now get foot cramps still, but find if I do some extra stretching in between rides it disappears.

Good luck figuring out what it is, sounds pretty painful!!