hiyer1

Over the last 2 seasons I had been struggling with sudden inner thigh cramps (feel like spasms, very painful and immobilize the leg) that have onset around mile 60 of Z3 rides/races. Most of my riding is triathlon. Through a lot of research and fit modification I've been able to alleviate it. I wanted to share what I've learned to hopefully help other riders who experience similar problems.

Cramping has generally been attributed to electrolyte imbalance, which is partly to blame but provides more questions than answers. For instance, if cramping is related to electrolytes, how come inner thigh cramps usually target only one leg or a specific area? And how come they occur more often while cycling and rarely while running?

It's because more often with inner thigh cramping the culprit is exercise induced arterial endofibrosis. Basically muscular inflammation of the groin muscles causes an artery in that area to get temporarily blocked; the resulting decrease in blood supply to the lower adductors and vastus medialis and is what causes the cramp. There are fit and geometry factors that can speed up the cramping. The endofibrosis occurs more often in cyclists who have seen a few seasons, which is why you don't usually see the problem when you first started riding, but it comes later once your fitness has improved substantially. It's also very common in triathletes, who have well developed adductors from running that, once inflamed, are much larger than those of a non-runner.

Factors that accelerate endofibrosis: Aero position, and knees tracking inward/toes pointed inward leading to overuse of adductors and gracilis on recovery phase of pedal stroke.

The solution I found was really very simple. Adjust float on your cleat so your toes and knees are pointed sufficiently outwards. You should be using your glutes when spinning up on the recovery stroke, not your adductors. The more you use the adductors/gracilis to pull, the quicker they get inflamed and the quicker you will cramp. During my last IM race I was able to delay cramping until mile 111, which was near perfect. Breaking aero position and spinning lightly (easing up on power) is also good way to prevent a cramp when you feel it coming on slightly.

Anyway, hope that helps. Please feel free to add your own experiences/findings

Some sources:

https://cyclingtips.com.au/2011/11/ex...-endofibrosis/
https://sportsmedicine.about.com/od/b...riopathy_2.htm

--
"It always seems to me that man was not born to be a carnivore...Our task must be to free ourselves by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty...Indeed, nothing will benefit human health and increase chances of survival for life on earth as much as the evolution to a vegetarian diet."
-Albert Einstein, collected from assorted memoirs

"Everyone says 'Where's your protein.' Well I ate tons of lentils, loved beans, had the juice; I did the things that I needed to do to replace what you would get with the tremendous amount of meat that most people eat"
-Carl Lewis, Nine-time Olympic Gold Medalist

dkeith83

How are you doing now? Still struggling with the issue? Have you considered surgery for this?

immanea

I am dealing with exactly the same issue for the past 2 years. Around mile 45-50 the inner groin gives out but it is different from cramping though it feels similar. I can get off the bike and run 8 min pace comfortably. I have been doing triathlons for 15 years and this only started in the past 2-3 years. Also happens on road bike not just tri bike. I just hope I have not damaged the artery so badly that I need surgery. I use gray keo cleats.. will try red ones to see if helps. I did go to shorter cranks but so far no difference.

Carbonfiberboy 

My wife rides horses, both jumping and dressage as well as riding our tandem bike and hiking. She gets adductor cramps but mostly at night. That's an interesting idea but it doesn't quite fit her as she doesn't get them while riding. She does have killer adductors. Could just be overuse in her case.

MoAlpha

Never heard of arterial insufficiency producing cramps. Pain yes, but not cramps.

noimagination

I was experiencing inner thigh (not groin) cramps for a while, too, but then I discovered that I'd accidently set my saddle too high when changing to a different saddle. Since I've lowered my saddle a bit, the problem has gone away. I'm not sure that there is a cause and effect relationship, but the saddle height change and the cessation of the cramps are correlated in time.

We may not be talking about the same thing, however, since you (immanea) say that your problem is "exactly the same issue" while there's a discrepancy between the problem described in the OP (hiyer1: inner thigh cramping) and in your post (inner groin).

(Yes, I'm aware that the OP is almost 11 years old.)

zandoval 

So glad you posted. Fantastic... You found a possible solution. Endofibrosisis is tricky. But via MRI with and without contrast the scaring can be found. You can also identify decreased return circulation precipitating the fibrosis by checking for compromised varicosities.

Man that's tough. Waking up with a big cramp that hurts for days is the pits. You might want to suggest that on those nights she knows she is going to have problems to wear compression garments. They seem to help a little. She may also benefit from Quinine. About 1/3 of the general population can halt bad nocturnal cramps using Quinine at about 500 mg. You can no longer get Quininesulfate even with a prescription. You can get regular Quinine in liquid form and or also use Hylands Leg Cramp tablets. Of course people who have cardiac meds need to clear the use of quinine with their Medical Provides. Some forms of cardiac meds do not get along with large doses of Quinine.