Hoping you guys might have any suggestions for this problem I’ve been having..sorry long post alert :roll:. Since around end of June, any time I do a hard effort for over 5mins, my left quad just slowly loses power until its completely fatigued. It starts at my vastus medialis (inside quad muscle closest to knee) and just kind of spreads outwards up my quad. Furthermore my quad/hamstring is a wee bit smaller on that side. I do around 15hrs a week of training (4hrs turbo on TT bike, rest outside).

I’ve managed to quantify the issue in a FTP test, using a powertap hub and a left-side garmin vector pedal. For FTP the power tap recorded 307w, but the left side only recorded 285w. My FTP is around 330w so it rings true that the left left is definitely bringing it down.

I’ve been seeing a physio for 3 months but they can’t seem to see a ‘magic bullet’ fix for the issue…my hip flexors are loose, my calf was a bit knotted but nothing obvious that would be causing the quad to fatigue so quickly(i.e calf/hamstring opposite muscles weren’t tight enough for the quad to have to push through that tightness). I’ve been given strengthening exercises for my hamstring and glute to try and get them firing more, but I’m still looking for that ‘quick fix’, primarily as the issue started quite quickly in July so it doesn’t seem like a slow deterioration of muscle power(I won two TTs in June so all was fine then for going over 300w!).

I’ve seen a bike fitter who specialises a bit more in the body/physio side of things and his machine could see I was a bit tighter down the left side (less ankle angle etc), and noticed I had quite high arches, but nothing that would be a primary cause of the issue (plus it happens on all bikes/shoe types etc). I’ve fitted superfeet inner soles anyway and that hasn’t changed much.

Sooo on to the pinched nerve! It started about 2 months ago..I’ve been getting numbness/tingling all along the front of the dodgy quad. It gets worse when sat down at my desk, and lying on that side in bed. The physio is massaging my lower back every 2 weeks and says it’s not very tight at all (it was at the start). I can ‘activate’ the tingling my doing the hip flexor stretch (dodgy leg kneeling, leg in front then move hips forward).

It is definitely the femoral nerve that’s trapped, but I’m wondering if that’s enough to cause the weakness/fatigue in the muscle? The physio says it only is a symptom when the nerve is fully trapped for long periods of time that causes the weakness (and knee buckles etc) rather than just the mild numbness I have. Could the nerve have been pinching for much longer before I had the numbness symptom 2 months ago(i.e July), and cause the issues I’m having? I’m wondering if it’s pinching whilst on the bike somehow, and instantly causing the fatigue..?

Finally, I’m absolutely terrified it’s this, but all the symptoms match..iliac artery narrowing: http://www.cyclingweekly.co.uk/fitness/is-surgery-a-cure-for-iliac-artery-furring-27258 (More info https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4212352/). If it is that, then I’m pretty much screwed as I’ll never be able to get anything like that sorted via the GP/NHS.

(Sorry for the long post, the problem is really stressing me out now! It was quite cathartic even typing that! Even if no one replies, at least I can copy/paste this to other places or emails to my GP friends!!)

Hi, my femoral nerves (i.e. Both sides) were pinched for years by a damaged disc that eventually totally disintegrated. It was gradual deterioration over 25 years after an injury in my teens. I ended up with muscle weakness (but not numbness) in my quads and had a spinal fusion 2 years ago which freed the nerves and restored my muscle strength.
If you have numbness and tingling that might possibly suggest a nerve issue. Why not go and see your GP as a first step?

Great thanks, yep I think a trip to the GP is in order as I’m not sure the physio can do much more for the nerve issue than the deep massage on my lower back.