Systemic cramping during races

Looking for some ideas about full leg cramping during racing. ONLY happens during races. Literally, never on a training ride - even ones pretty close to race pace. These are not single muscle cramps - literally I am off the bike with quad/hams/adductors in full tetany (or as close as one can be). It will be both legs at once - it is like my whole lower body just goes into spasm. I can feel it coming on with some fasciulations and then, boom, a few minutes later both legs just seize up. I feel like I know all the things - sodium load, hydrate, train, magnesium in daily life… and I do all these things. The frustration part is that I can not mimic this in training and so I can’t figure out how to address it. Is the most likely culprit the exertion level of the race since it only happens in racing? I should add these are longer races (today it happened around mile 20 of a 50k mountain bike rice) and the last two years around mile 30 of this same race but the 100k. I felt really confident in my training going into today’s race and according to Strava (which shows a moving time) if you subtract out the time I stood on the side of the road unable to move, even with easy pedaling after the cramping I still PR’ed my time on the course by 6 minutes… which tells me… what? That I didn’t train hard enough? Or train close enough to my limits at times? I’ve attached the power zone graphs from Garmin. The one with a little of Zone 7 is the race ride. They don’t look drastically different to me… so how come I can’t race without ending up on the side of the road with my legs completely locked up? :disappointed_relieved:

I suffer from the same phenomenon.

My hypothesis is that I don’t push as hard during training race simulations because I don’t have the same adrenaline spike that comes along with a race. I also usually have a hard time sleeping before big races, which is not something that happens before my big rides.

My strategy is (in theory) to take it easier at the beginning of races and see if I can avoid the cramps. I have cramped in 5 of 6 of my last races… lol

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Well I’m glad I’m not alone :slight_smile: I’ve never met anyone in real life who experiences this. I had the same thought about going easier! And I did. Power for the first 20 minutes was totally reasonable. Last year I went out like a bat out of hell and very intentionally did not repeat that. But my efforts on the 3 big climbs were higher. But again, not much higher than a close to race effort training ride with the same pre-ride dinner, intra-ride fluid/CHO/Na, time of day, etc etc on the same course. And I felt amazing on that ride…

I too am a cramp victim, and most often during races (mostly MTB, with some hill climbs). Over several years of trial and error I’ve landed on a few things:

Hydration + electrolytes- I’m a moderate to heavy sweater, but my salt loss is off the charts. A 2 hr ride .7 IF ride in sunny, mid 70’s F turns every black part of my kit gray, and my exposed skin is covered in salt crystals. I MUST have a high-electrolyte mix in the bottles or I’ll lock up within an hour.

Carbs - I have found that if I let myself get low on fueling, even a little bit, I am vastly more likely to cramp. And punchy MTB races make the risk much higher.

The race effort itself - there is no workout that is an adequate model for an actual MTB race (or likely any other non-TT race). The power demands can be crazy, especially in the starting minutes of an XCO. You’re going to generate a lot of fatigue very quickly, and not be able to shed it for a long time. That takes a toll, and coupled with either, or both, of the above can be a short trip to cramp city.

My preventatives, though not 100% effective, help a lot. High electrolyte concentration bottles (PH 1500, 1.5 tablets in 24 oz), lots of carbs, > 90g/hr of maple syrup and Clif Shot Bloks, and as much race-like MTB riding as I can squeeze into my life. If you can, do a bunch of B and C races and use them to try things out. If not, find a faster-than-you friend to rip your legs off for you, and simulate racing as much as possible.

Good luck!



I have this happen in crits. Sometimes it impacts the race and sometimes I can skip some pulls and recover. Usually get it from going harder then I have all year and shakes its self out after 10 races


Similar issues here. I used to cramp a ton (honestly had an event I cramped so bad in I thought about quitting cycling). I did a ton of research on it and it’s disappointing that once you dig into it there aren’t a ton of unbiased (not by the hydration industry) studies out there.

I originally band-aided it by throwing a ton of electrolytes at it (Precision Hydration) but what really helped was training. My opinion from the research is that cramping is caused by over-use/stress and a way for the muscles to try to prevent you from destroying them. I think that “excessive” hydration/electrolytes can lengthen the time before you get to that point though and hence the confusion in the studies and why everyone has their own individual solution to them.

I thought I had upped my training enough that they were a thing of the past but half way through a rather brutal gravel race yesterday I started to cramp. Luckily most of the hard climbing was over and I was able to keep power low and spin it out but it clearly impacted my result.

I haven’t looked at my files yet but I think my issue was that not only did I push too hard at the beginning to stay on but also pushed between the climbs to again, stay on. In training or hard rides outside of races I typically have my hard intervals, climbs, KOMs and then back off. Not saying I was 110% everywhere yesterday but instead of 110% then 50% during training I was 110%/90% and I paid for it.

Going to try to train more intense (conversation with my coach I need to have), up the hydration again (thought I was past them so focused more on carbs than electrolytes), and maybe but some more mobility work into my training as I’ve heard that may help. Could just be part of a group that has cramp-happy legs though so who knows…

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@Lorichka6 - WW100K / 50K, right?

If so, I bet you’re going out harder than you think you are on the climbs in the first half, and going above threshold more thank you think you are, followed by endurance and potentially singletrack, and in the case of that course some LONG descents that are hard on your legs in a different way (basically a long wall sit…) That course has some STEEP climbs that can be hard to stay below threshold.

Where are you climbing relative to your FTP early in the race? Have you looked at the race files?

I would ask yourself if you’re ever really doing training workouts that match that profile of the race. I almost never put a hurting on myself in training the way I do in a race like that. Legs feel pretty trashed today :rofl:

(If I’m right on the course - it’s XC MTB, long steep ascents and descents that are rough and bumpy, and some singletrack too, so MTB Bike Fitness, Descending Muscles, Descending technique and conditioning comes into play)

I think we are reading the same research. The un-sponsored studies seem to show that while sometimes water only → cramps, high electrolyte drinks don’t solve the problem across the board (making me think it can’t just be electrolytes). One study on triathletes showed that going harder (hmm…) and having had cramps in the past (hmm…) were the best predictors of cramping during an ironman. Electrolytes didn’t. I definitely “found” a whole proverbial next gear in this race. My time for the first half of the 50k was 11 minutes faster than my old PR. I never would have thought I could ride it that fast. Maybe 1-2 minutes faster than my hard training ride, but 11… so clearly I am not training at a level close to my high end really is. Or maybe it is closer to what you said about 110% to 50% in training vs 110% to 90% in races. Either way, it is really hard to mimic that in training. Can you tell me what your coach says? I’m interested to hear a coach’s thoughts.

Have you found carbs helped? Stupidly I didn’t bring any rescue electrolytes with me on the race (only had ~1 g in my Skratch). So when the cramps started I ate some jelly beans hoping maybe carbs would help. I did improve for a bit (but they came back 2 more times). But obviously there was no salt in there to help. I’m wondering if more carbs for these super intense rides might also help. I probably under fueled with 88 g CHO for the whole race in 1L of water. That was only ~40 per hour.

Yes, WW50k. Last year I was talking to Patrick after the race and he said the pack was doing 300+W down Springfield at the start. I held on for a bit last year (riding without a power meter) and was shocked to hear that because it didn’t feel that hard. This year I rode with my power pedals and did NOT repeat that. I still rode harder than in training (we have a house here so I did the 50k 4 times prior to the race) but at a wattage that seemed reasonable. I actually think a lot of the damage was done passing people on Bartlett because I had let so many people go trying to keep watts under control for the first 5 miles. Lots of short little efforts to get back on the good gravel after passing someone. I need to figure out how to see avg power for just a certain segment on Garmin - but I’m sure you are right. I bet my Bartlett watts were significantly higher. After the 50k split I was able to ride my own race more and feel like I didn’t climb Lacy that much differently than normal.

Interestingly, I feel fine today. Just did a 2 hour ride at Hardy (because I’m here, so I have to, right?) and felt good :woman_shrugging:

What I’ve read and had myself long ago, not that much lately (except Sunday :rofl:) it’s mostly lack of hard enough stimulus. Hard enough anaerobic sprint and power sprint workouts that really tax your muscles in neural level and ramp up lactate. If you have for example Golden Cheetah, you can take a look how much matches you burn in your typical races and what size of matches (w’ and w’ load accumulated) and how your hard workouts balance with this against your racing needs.

Too much tapering can cause this too, you need to taper to get the best out but it’s a balance. This probably caused my Sunday cramping, but I have yet another week to balance I believe.

Magnesium never solved problems for me, only hard training did. My old personal doctor who worked quite high level ice hockey team as leading doctor always reminded me of calcium…because it is a messenger in neural signaling chemistry. Well I drink milk quite much and some cheese and yogurt and and…

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Yep, exactly…my head spun when reading the research and it was hard to say X fixes it so I really threw the kitchen sink at it. I’m waiting for results to be posted as I didn’t look at the “live” results post race to see how disappointed I should be and then debrief with my coach, I’ll let you know what he says around cramps.

I do think adrenaline has an impact on RPE, especially early on. At the start I was putting down some power that although not ridiculous should have felt hard but it felt more like Z2. Could have also been fresh legs as I tapered after some pretty intense weeks prior. There were some ridiculously fast riders here (winner averaged 20+mph over 56 rough miles with 5500’ of climbing) so staying on that lead group was never going to happen but the race broke up quickly at a rather technical climb early on and I was never able to find “my” group which didn’t help. On the to do list for next year is to learn how to climb faster over crappy terrain.

Carbs don’t seem to help as I was taking 80-90/hr which is about the max I want to push. I think they might have helped me ride them out though as that’s something I couldn’t do before I upped my carb intake. Of course it could just be the more intense training (problem with throwing the kitchen sink here). Might be worth a try to see if it at least lessens yours? 40/hr seems low.

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Yes, this is it. Long time experienced racer here, and I am a cramper. Generally only happens in races, but I have been able to do it literally a couple times over the past 20 years in very very long hard training rides. Have tried most everything, but never found a silver bullet to eliminate it. Certainly managing pace/workload helps in a race, keeping cool, electrolytes, carbs, etc. Can all help, but nothing has solved the issue.

Racing more often helps, so does increased fitness. But more often than not, in a long race, if I am going all out, it is likely to come on.

What to do? Train as best you can. More racing or race simulation. Keep on top of cooling and nutrition but don’t expect miracles. I have just changed my mindset. I don’t love it, but know it is a part of racing for me. I try to manage it, but in the end, I look at it as a sign I truly gave a max effort. I gave everything my body was willing to give - until it went haywire.

When they come on, ease off the pedaling if you can, or get off the bike until they pass. Usually, once I get through them, I need to go relatively easy for a bit, but can then ramp back up to my pace after some time.


I personally track NP instead of average, set a field on my Garmin for Lap NP, and hit the lap button before each segment. For example, right turn onto styles brook, hit lap, and target 80-85% IF/NP for the climb trying to pedal smooth. Hit lap again at the top to monitor np for the flats.

Allows you to make sure you’re keeping np under control for individual segments instead of the entire course or just watching 3s/10s figures.

Probably hit lap 15+ times yesterday (edit - 17 laps)


This. Lap NP and overall IF.


During the race while I was just spinning in an effort to try to just stay on my bike I started fiddling with my garmin to see my NP. I couldn’t figure out how to add it as a data field on my screen. I must have been looking in the wrong category. Adding this and the IF (@mrcrankyandangry - thanks!) and lapping more often are so obvious in hindsight. Year 4 at this damn race is going to be my year :rofl:


Please stop mixing units! ‘k’ means kilometers or thousand, not miles.

Regarding the cramps, you need to do some max sprint training on days when you’re rested. Also do max sprints mixed in with a sweet spot or threshold session. It will help your muscles become adapted to the intensity.

You may also need to do some race simulations where you push yourself to the breaking point and keep going anyway. The best way to do that is to ride with people faster than you on a drop ride and refuse to let yourself get dropped. Even if you get dropped, chase back like there’s a bear chasing you. Even if you pop you just can’t stop pedaling.

Can I get some more details on lapping the NP? I would understand doing that with average power but isn’t the benefit of NP that you don’t have to worry about the lower power/coasting sections?

I guess if you went way over or way under target NP it’d make sense but even then I’d argue you’d want to go easier or harder from there on out to get it back near target.

What am I missing?

NP is still important on sections because in the real world your power isn’t smooth. I just looked at NP vs Average for one of the climbs in the race mentioned, and even that was a 15W difference.

Sections with descents and singletrack sections I also have (different) pacing targets, and for every section I want to make sure I’m hitting those targets (or at least monitoring) without influence from prior sections, thus why I’m using the lap button so frequently.

I’ve also said this elsewhere - in this race I would wager 75% of the field goes out WAY WAY TOO HARD. From the midpoint, I wasn’t passed by anyone, and probably passed 30+ people in the last 50K, and I think did a negative split on NP for first half / second half. Plenty of people just crawling up some of the climbs and dying a slow death on the road because they paced too aggressively up front, and it was cool to start, getting hot and sunny by the end which made it worse.

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Thanks for the useful help but why can’t I say mile 20 of a 50k race? Do I have to refer to any mileage points in the race also in kilometers? Or should I call it a 31 mile race so that I can refer to mileage along the way in miles? Geez…

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