Extreme quadriceps starting pain after 3-4 rest days

Page 11 - Get up to date with the latest news, scores & standings from the Cycling News Community.
Jul 7, 2015
Very interesting, pasaglia. If you are happy to share findings from your muscle biopsy, I'm sure many of us would be very interested indeed.
I absolutely will. Very sorry for the late reply. I'll have the biopsy in October so I suspect I'll have the results late October/ early November. WiIl post as soon as I have them.
Feb 17, 2016
Hi budegan. Very sorry for the late reply. I haven't logged in in a while.

I think it is certainly rhabdo (the breakdown of skeletal muscle) as confirmed with a CK test too many times. I think that is the pain we are all suffering with. But the rhabdo is just a symptom of an underlying myopathy.

My CPT II genetic test was negative, so perhaps it is something like CPT II that has not yet ben identified. I also read on the Mayo clinic site that CPT II genetic tests can give false negatives. So perhaps it actually is CPT II? The biopsy will hopefully reveal something. Going the first week of October and will share the results as soon as I have them (presumably late October).

Laid out with the flu at the moment and cannot run. Chugging gatorade which seems to be pushing off the worst rhabdo. 23 hour flight to Vietnam tonight, and having Gatorade gives me a lot of confidence that I can do it.

Sorry again for the late reply.
Sorry to hear that you're not well - I hope that you made it through the flight okay!!!

Thanks so much for replying, and very best of luck with the biopsy. As has been said in similar circumstances previously in this thread, it seems like you're taking one for the team so thank you!!!


Sep 28, 2019
So glad I found this thread so I don’t feel alone. Unfortunately I have no answers. Just sharing my experience.

51 years old. Been riding for decades. Some years more, some years less.

I had a slow start this year, but have worked my way up to decent fitness, riding 8-10 hours/wk, with no more than 2 - 3 days off, for the past few months. But last week I came down with a bad cold which had me off the bike for 6 days. When I finally hopped on my trainer for a light spin, within 15 minutes, bam! Intense pain/cramping in my left outer quad. I tried to push through it, hoping it would loosen up, but to no avail. I could barely walk for an hour afterwards, but the pain receded by bedtime.

I was feeling fine the next day, so I tried another easy spin on the trainer. This time I made it about 35 minutes before the pain returned. However, it was now on the inner part of my left quad. I stopped immediately, since pushing through it didn’t work the day before.

Then today, again feeling better and hoping for some progress on the 35 minutes, I hopped on the trainer. Just 2 minutes in the pain hit my left inner quad. I knew there was no pedaling through it, so I stopped, mad as hell that I couldn’t train, and searched the web for some clues, which lead me here.

This is the first time in my life I have experienced this. It’s just so baffling for it to come out of nowhere after so many years of cycling. It’s bad enough that I was forced off by a cold, then this hits. I hate being off the bike, knowing I’m losing fitness that’s increasingly hard to attain and maintain as my age progresses.

Guess I’ll give it another shot tomorrow.
Jun 5, 2018
Dear fellow sufferers and cycling colleagues
I am a paediatrician from Brisbane. I would’ve been on the forum much earlier but I’ve had trouble logging in for quite a while realising it was my browser.
I am drinking my endura rehydration solution as we speak. I think I have cracked the case but unfortunately don’t have any proof at present. I do believe we share a common condition related to an abnormal enzyme glycogen synthase the same as in the horse polysaccharide storage disorder PSSM 1.
I have not looked into it any further but I’ve had a number of investigations including muscle biopsy and metabolic testing. I have had the symptoms for 20 years and had many episodes have rhabdomyolysis and unfortunately didn’t realise until reading this post a few years ago that it is the same condition and I’m not the only one suffering . The pattern is similar. If I ride regularly I never get any symptoms at all, no cramps, no pain, can ride as intense as I like,and forever (I am a very average cyclist at best (see Mcgilla on Strava)) however if I have more than 2 to 3 days without riding my bike, I get rhabdomyolysis on trivial exertion eg walking. This goes against the grain for previously described rhabdomyolysis, that is it is related to overexertion or inadequate fluids, hot weather etc. There is nothing in the literature about this condition in humans but I think we are onto it. I’m convinced it’s related to an abnormal glycogen synthase enzyme as a primary or secondary event. I do believe that Steph Valberg finding this condition in horses is embarrassing for us poor humans. My theory for it not being that common is it tends to come on later in life and not many people are athletes like us (he he). My first episode came on after doing a half marathon when I was 26 years of age. I stopped running for a few days and had my first bout of rhabdomyolysis in my calves. I started cycling as mentioned 20 years ago and it’s only come to now to realise what the problem is. I’m hoping that we can come to that answer and I do believe we all have, a never described condition in humans, a variety of PSSM1 or very similar. It could also be possible that another protein called glycogenin could be at fault. The only way to prevent it is to exercise regularly without breaks and have a low carbohydrate diet. The main reason I want to have this formally diagnosed is my wife just thinks I have obsessive cycling disorder and won’t let me take my bike on holidays even though I’m always limping around even after a short walk ( as well as help you guys). I’m looking forward to hearing everybody’s feedback. My overall plan would be to have a study done, potentially have as many people as possible have bloods sent to a metabolic laboratory in whichever country, I just don’t know what to ask for yet but do have a metabolic colleague who will be giving me advice. If I wasn’t so busy at work I would have enough time to organise a website where everyone put their details ( privacy issues of course) eventually write it up as a medical paper although I am not into research, I just work clinically (let me know if someone out their does research). Be keen to hear your responses on such a frustrating painful condition.

Dr Mike McGill
Suite E, Ramsay Place
137 Flockton Street
Everton Park 4053
Brisbane, Qld
Jun 5, 2018
I had the quad pain episode Monday as described 2 posts up. This morning I went to a sports PT who thought it was a classic overuse injury. I disagree with this diagnosis. The level of pain, the unfocused nature of it (different specific muscles in each quad), the unusual triggers (spinning easy after a rest week), it just doesn't make sense. I am a well trained athlete but I am not overtrained.

I tried riding again today, pushing a little harder from the beginning as somebody up-thread suggested, but I didn't make it 5 minutes from my house. I had to walk home. There was no question of pushing through the pain, when I got home I was afraid that bending my leg would rip the quad in half. I can understand how some sufferers have gone to the ER for fear of compartment syndrome or some other emergency. I can move around now but my legs feel sore and bruised, as if they were beaten with a pipe.

I feel that I can rule out a localized physical cause such as muscle pull, trapped nerve, etc. The pain is on both sides, and the specific affected muscles were different today than they were Monday.

I don't see any alternative now except to take yet more time off the bike. This is very disappointing to me as the racing season has just begun and this is usually my best time of the year.
Jun 5, 2018
Hi all
I've had a number of episodes of this issue and have been working with my coach (Phd with focus on sports science and genetics) and some sports doctors, and have come up with a hypothesis as to what is going on:

Onset of the condition in my case:
  • relatively high training / racing load
  • 3-4 days of inactive rest
  • normal / increased carb and sugar intake during the training load, and importantly no moderation /and often an increase in carb and sugar intake immediately during the rest period (ie pigging out a bit post a stage race / big block, or at least not reducing intake during this period)
  • pain as described above, in quads, calves, hammies, abductors, glutes.
  • importantly the fact that during an episode the pain moves around (anterior, posterior, right leg, left leg) indicates that this is not a nerve/skeletal issue
  • significantly increased CK levels indicating some for or myopathy
  • CRP levels normal indicating that it isn't an autoimmune issue
  • the issue is an enzyme related issue in the muscles specifically related to the production of glycogen synthase.
  • glycogen synthase is the enzyme which is responsible for converting glucose into glycogen for storage in muscle cells.
  • in a "normal" person, during high load, levels of glycogen synthase increases in order to store fuel to meet the increased requirement for energy for the body. When exercise load decreases, the body automatically regulates the level of this enzyme as the body's need for stored glycogen reduces.
  • the theory that we are working with is that in my case, the body is not regulating this enzyme level, and so the body is continuing to convert glucose into glycogen and packing it into the muscle cells.
  • the problem is twofold in that firstly exercise has stopped and so the glycogen is not being used (but continues to be stored) and sugar and carb intake has not reduced (and often increased) so there is excess in the body and it is being stored.
  • the theory is that the muscle cells get overloaded with glycogen and when exercise is introduced, the cells literally tear as a result of being overloaded.
  • this accounts for the pain felt, as well as the increased CK levels.
  • the hypothesis is that this is a genetic issue and there isn't a "cure" as such
Prevention and treatment
  • active rest as opposed to inactive rest has been effective in preventing onset (ie. 90 minute low intensity sessions with not more than a day of inactive periods).
  • significant reduction of carb and sugar intake as the rest period starts
  • during the most recent episode I went into a LCHF (virtually carb free) diet and within 2 days had no more pain
  • during the episodes, multiple, short (10-20min) sessions until onset of pain, with aim of stimulating metabolism and effectively burning off glycogen
  • once pain had subsided, introduced low intensity IMTG rides for the first few sessions.
  • use of ibuprofen to assist with inflammation in Muscles and for pain during the episode
  • increase water intake to assist kidneys with CK load
As I said, this is a theory that the guys i am working with have come up with and it seems to make sense and be working for me. I'm sharing it with you simply because I know the frustration and the pain associated. If (and hopefully we don't have another episode given our prevention strategy) we have another episode, we will need to do a muscle biopsy to test the theory - obviously invasive so would prefer to avoid!!

Once again, this is a theory - hopefully it helps!!
Hi Drewza101
I think you are spot on with the number of your suggestions as per my recent post #254. I do believe the condition we have is related to glycogen synthase being overactive adding too many 1,4 glycosidic bonds compared with 1,6 bonds which adds extra glucose onto the glycogen chain but continues to be upregulated If there are too many rest days (>2 days) and is not turned off sufficiently once exercise is has begun. I suspect it is the polysaccharide storage disease described in horses, never in humans. I suspect there is a polymorphism in glycogen synthase described by Stephanie Valberg in horses 20 years ago. I do believe the answer will be in serial muscle biopsies showing increased normal glycogen levels in rest days, possibly a DNA test. It disappointingly has never been described in humans but it looks as though most people who are posting this have the same condition, guessing it is more common than we think. There are 15 glycogen storage diseases and this has never been described in humans and I suspect we are onto something.
It has nothing to do with stretching or any other condition and Unfortunately I don’t think any treatment will be available for cure. The key is to exercise frequently, the draft horses have at least a 20 minute run per day and they don’t get the disease, They also swear by a low carbohydrate diet which may be a possibility. It does appear in the muscle biopsy of horses that there is an abnormal glycogen. My muscle biopsy did not show abnormal glycogen so I suspect it is due excess normal glycogen And unable to turn off the glycogen synthase which keeps over producing glycogen .
Feb 17, 2016
@mickmcgill68 - this is extremely interesting.

Amen to "The main reason I want to have this formally diagnosed is my wife just thinks I have obsessive cycling disorder and won’t let me take my bike on holidays..." (although fortunately my missus is incredibly understanding about it - even if she thinks it's all in my head!).

Thanks a million for posting and count me in for the study :)
Reactions: mickmcgill68