I don't know about how ITBS might relate to crank length, but can tell you that the only way I have been able to keep ITBS at bay is to stretch and roll my IT bands religiously every day. Not a really big deal in my opinion. Your PT is probably telling you now how to stretch and roll.

It can certainly can be fit related---could be cranks, or other hip/knee/foot related items. I fought ITBS on the road bike (left knee) for a couple of years. I finally got a proper fit from Boulder Center of Sports Medicine. Besides the normal "fit" stuff, they made a couple of adjustments specifically to ease the ITBS:

1. Longer pedal axels to open my stance a bit. Keeping my knee more in line with my hips.
2. Added some wedges between my shoe and cleats on my left side.

I over-pronate on my left side during the downstroke. So, my left knee was diving into the top tube and putting tension on my ITB. Prior to the changes my left knee would frequently tap the top-tube as I began to apply downward pressure to the pedal. Note these changes were specific to me and my bones/mechanics. I'm not suggesting you make the same changes...except perhaps to have your fit evaluated at some place like BCSM that specializes in sports injury related bike fit. In injury related fit questions, its best to make those changes under the supervision/advice of an experienced medical expert (just like custom orthotics).

In addition, I did ITB stretches, and muscle activation therapy (exercises, estim, etc) (all via PT with a cycling specialist) to train the correct firing sequences in my left quad. Additionally, I was advised to stretch immediately at any detected onset of discomfort. I learned how I could stretch the ITB while on the bike---so I didn't have to stop and get off. You're just trying to break the reflex-arc...ITB pain causes you to reflexively hold tension, which causes more pain, which causes more tension...etc. The stretching helps to break that cycle.


[[[EDIT: I originally had the legs flipped around. After writing this I went for a ride and tried the stretch---verifying that I had written it up backwards. I've updated the description to correctly describe the stretch. ]]]

Basically, stand and coast, and level the pedals with the 'leg to stretch' to the front. Let the ankle drop like a calf stretch, and lean over at the waist like a hamstring stretch. Once in this position, bend your opposite leg at the knee and let that hip drop---basically relax. You should feel the ITB of the affected leg stretch around the hip. Sometimes I will also twist my torso, to help put more tension on the ITB. I generally hold this for 30 seconds or so. By then its usually time to pedal a bit. I generally do both legs, and might repeat the stretches after about another 5 minutes of pedaling. Back then I would typically be good for 60-90 minutes before needing to repeat the process.

After the fit adjustments and the primary PT was completed, it probably took six months of continuing the on-bike stretches before I rarely had to think about it any more. 12 years later, no recurrences....but, I still do it now during my warmup, mostly out of habit and as prevention of relapse.

100% anecdotal, but I had some IT band issues that I fixed with shorter cranks.

I always found it tough to get a position, I either had my saddle too high and would develop saddle sores from my hips rocking or it would be too low and I'd develop IT band knee pain.

I switched from 172.5 to 170's and was immediately more comfortable and could fine tune my position better since, with the shorter cranks, I could get a little lower on my front end.

When you went with shorter cranks did you adjust saddle height at all?

If my saddle is a smidge too high I have almost instant IT issues running. Curious if your immediate comfort might also have been related to a lower effective seat height via the shorter cranks.

Yes, I think I actually raised my saddle but I didn't keep track of measurements. I experimented a lot since previously +/- 2mm would mean knee or hip pain. Now I can adjust the saddle +/- 1-2cm without issues.

Thanks for the replies.

I ended up picking up an IT band strap and was able to go for 1.5 hours on the trainer today between 65-75% FTP with no pain. I think I will keep my rides short and easy for the next couple weeks as to not put much strain on the ITB while hopefully minimizing the fitness losses.
At the same time I will be pounding my arse.....with the glute/hammy/hip strengthening exercises. Looking at the positive here that this didn't flare up a week before my 'A' race. Still have a few months to get some strength back in the butt and get back to the bike fitness!

---

Ask me how much I love my Kiwami LD Aero Trisuit

Note: I originally described the on-bike ITB stretch incorrectly. I had the legs reversed front/back. I've fixed the original description to be correct.

Do what works for you---Short is good---extend the duration as tolerated. But, you might experiment with the intensity...after a few days. Sometimes I found that easy was worse for whatever reason.

You won't lose anything appreciable in a couple weeks of reduced volume---especially if you compensate with S/R. Or, if intensity doesn't cause pain, then you can trade THAT for the reduced volume...and could even come out stronger on the other end. Whatever you do, stop / stretch at the first twinge...never ride through the pain.

I agree that there is a bit of a sweet spot to find in regards to intensity, when I go too easy, it will start to hurt, likewise if there is a power spike. I will definitely be using your on the bike stretch to keep it as loose as I can,

---

Ask me how much I love my Kiwami LD Aero Trisuit