VO2 Max training, knee issues and a very close A Race

Hey knowledgeable folks of Trainerroad

I’ve been using Trainerroad for a few months now and am feeling good overall, and strong on the bike outside as well as hitting all my workouts inside. I have an A race in the middle of January which will be a 24 hr mtb ride - so hopefully absolutely minimal Vo2 anything! I’ll be plodding along and only using effort to get up climbs that would otherwise have me off and pushing.

However, I have started noticing knee issues when I am doing VO2 intervals. They have been part of the program for three weeks now, and each time I have a slightly uncomfortable/weak/sore knee after. I put this down to the faster cadence (that I am not used to) and sloppy form. I may be wrong about that, but it seems the most logical answer. I have come from training with a very slow MTB cadence in the 70s. Even on the road bike I doubt my cadence used to get over 85. On the Kickr, my comfortable cadence is a surprising 95-100 and I spin faster than that on VO2 intervals. I have no problem completing the intervals so far, if anything, they feel much easier than sweetspot work.

I know I need to sort this problem through appropriate training/technique, but right now, I just want to focus on the A race and what I need for that.

So, should I:
a) replace the VO2 max intervals with another form of workout - if so, which one?
b) modify the VO2 max internals -if so, how?
c) drop the cadence and see if I can muscle through the intervals as they are?

Do I even need VO2 max intervals as part of this race prep?

Any input appreciated :slight_smile:

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High cadence VO2max sessions are recommended way and you need them improve and make it comfortable for plodding along etc so I wouldn’t ditch them altogether that would just be masking the problem which is could arise again (at worst and I hope not in your A race). I would ease back on them just now and if you are doing them on ERG switch it off and do them how is comfortable for you. ERG was the source of my knee niggles a while back. Its maybe was the quality (or lack of to be precise) but I found it would ramp up resistance faster than I could cope with or turn it completely off too fast when I was at a high cadence. If you have any future problems though get it checked out by a physio ASAP.

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I usually do my 3 to 5 minute VO2 efforts at a cadence of 80-89. Try lowering your cadence a little next time and see if the knee pain is a little less.

Actually, I would consider getting a bike fit. It can be hard to find someone with the breadth of knowledge needed. However, you said your form is sloppy at high power. Is that sloppiness caused by your bike position? Is it caused by muscular imbalances? A good fitter can address both types of issues. Or does it arise just because you are weak and soft? Then perhaps you need encouragement, but many serious cyclists would still benefit from bike fits.

And yes, position issues and body issues can cause knee pain. I had my saddle too high, like probably a number of performance-oriented cyclists. Eventually I got knee pain. My fitter lowered my saddle by 20mm. That’s nearly an inch. Well, I’ve never had any sustained problems after that.

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@JoPage set up your phone or GoPro to video your pedalling technique during these efforts. From behind & from the side at least. Maybe you’ll notice some things about your pedalling technique that will help.

A lot of times pedalling technique will change at higher workrates & cadence.

Are you using the same bike inside on the trainer that you race outside?

Overall, this reads like an issue where you are spending time at power zones and cadence ranges inside that you don’t use outside. Broadly speaking, I think it’s best to try and train in ways similar to how you plan to ride/race outside. Using a cadence range notably higher in this case, than the range you use outside may lead to some less than ideal conditioning and prep for your body and mind in those efforts.

All that said, stepping up to faster cadence as you’ve done is a common issue for riders who don’t have the ability to cleanly handle that motion. Choppy bouncing and irregular movement of the legs are something to be refined and improved if those higher cadences are part of your goal.

I do think it’s good for people to widen their range and fill in the areas they lack. But when heading in the the faster cadence range it’s good to do it in smaller steps. Try 5-10 rpm faster than your default cadence and make sure you have a handle on that before going to faster cadences. I think that’s better than jumping 20+ like you are doing and dealing with problems you can already sense. Dial it back a bit and work on form first.

  • Proper Practice = Proper Progress

you really should describe the type of knee pain. Is it the front of the knee? I have Patellar Tendonitis in the right side. It sometimes flares up when doing full effort intervals during the winter and then impacts less intense riding too. Hip flexor stretching helps and a bike fit would probably be a longer term solution.

Recently a doctor mentioned a patellar tendon knee band. I could tell it instantly made the knee feel better just sitting around and was very critical when on the bike to prevent flareups. They are like $10 on amazon.

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Do you strength train your lower body? I dealt with bike-induced knee pain on both knees for the last two years and it wasn’t due to poor bike fit. I saw a respected fitter and he determined everything looked good. However, another fitter who happens to be a physical therapist determined it was because I had neglected working on my glute strength and hip mobility. I had poor hip strength and mobility. Once I started addressing this—and it took a year or longer—those weaknesses and my knee pain went away.

That isn’t to say that bike fit isn’t the cause or isn’t important, however, it’s not a magic bullet and working on lower body strength could help you and is good general practice. The funny thing is, most people will immediately point you towards a bike fit (probably because it’s easy to do) and bike fitters rarely advocate for strength training.


For what its worth, I had the same problem while using TR plans. I appear to have resolved this issue by switching to doing plans with more endurance riding - about 6+ hours/week. My “I’m not a coach” explanation is that doing more endurance provided the conditioning I needed to do hard intervals.


Even if your race won’t have too many VO2 max efforts in it, over the course of 24hrs, you’re certainly going to rack up plenty of time in that zone. You’ll also still be training and preparing your body for the demands of your event, and fitness from each zone you train has crossover with the other zones you’ll be riding in. We’d recommend trying to stick with your VO2 workouts if that’s possible.

We’d also strongly advise seeing a physiotherapist/expert when it comes to knee pain like this. It’s tough to get to the bottom of these issues on the internet. We do have a lengthy Forum thread on this subject from the past that might be worth taking a look at – but if your knee pain persists, seeking professional help would be the right move!

Ahh, thank you everyone, lots to think about here.

@MN_XC and @anthonylane I probably didn’t elaborate enough about the knee pain in the initial post (not wanting to be a moaney snowflake) - I have long term knee issues which have been seen by various experts over the last 25 years, and which have been rehabbed in various ways over this time, but which culminated in a meniscus tear a couple of years ago. I have raced a 24 hr when it was still healing and it didn’t worsen it. I do, however, have to undertake long term forever maintenance physio. Squatting heavy weights helps loads, and I have various other glute activation work (clam shells, bridges, complex bridges, hip stretches, glute stretches etc). I have had to reduce the squatting significantly whilst focusing on the training though, as it just takes too much out of me and I need a couple of days to recover. So the reduction in squatting may be partly to blame, however, until starting the VO2 max work I have had no issues with the knee outside of the normal careful management. Even now, it is only the VO2 max work that causes any issue. I rode outside tonight on my enduro bike, with a stuck on brake, and my knee felt better after riding than it did at the start, because I know how to focus on activating my glute in that leg.

@mcneese.chad - thanks so much for your input. I use my road bike on the trainer and I will be racing on my XC mtb in January…but I have always trained and ridden on a mix of bikes (roadie, hardtail, xc susser, enduro bike). I have ridden 1000s and 1000s of kilometers audaxing on the roadie which is now on the trainer so it’s not an unusual position for me. Although I appreciate I probably should have the XC bike on the trainer for the upcoming event, the fact is, I am very time pressed and it is far easier for me to have the roadie on the trainer and the XC bike always ready to ride outside. It makes more sense for me to get my XC bike miles in outside as I am still getting used to the tyres and I need constant reminding that I can’t throw it around like I do the big bike with big tyres or I end up on my arse :rofl:

I have had a bike fit previously on the roadie, a long time ago, but I have since dropped my saddle (actually have on all bikes) since the meniscus injury to ensure better glute engagement. So I agree with you there @Weiwentg about lowering the saddle.

So as I say, it is only the VO2 max work that is triggering the knee pain. However, reading all the replies above, it sounds like I need to keep it in there. I will try a few things:
a)Turning off the ERG - thanks @HLaB for that suggestion.
b)Reducing cadence for the VO2s thanks @stonerider - I’m not sure I’ll manage them that low, but I can certainly reduce a bit. so I can concentrate on form more. I guess I can always turn down the intensity if I am struggling to muscle through it.
c)Videoing is a great idea, thanks @Brennus

In terms of why my technique is sloppy at higher cadence - I think it’s practice, or lack of it, at that kind of leg speed with flat pedals. I now run flat pedals on everything (for other special snowflake reasons I won’t bother going into) including my roadie, and I just haven’t ever done these kind of cadences with flats.

I’ll also add some squatting back in. Maybe this entire thread is just a good reminder that I need to prioritise the physio above everything, even FTP. Because if I am injured, FTP is totally irrelevant, isn’t it?


Every doctor when telling them your knee hurts riding your bike… :rofl:

“Stop riding your bike. Take 6 weeks off and if it still hurts come back.”

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I’m going to throw this out there. I injured my knee doing steep climbs. Something internal. I started taking collagen to see if it might help. I kept riding and over time the pain went away. This is not very scientific so who knows if it did any good.
Just a thought.

Good info overall, and specifically with the bike question I had.

Using a road bike on the trainer is fine IMO. I use one trainer bike (old endurance Roubaix) for all my training. That is despite using 2x MTB’s, 2x Gravel bikes, 2x Road Bikes, 1x TT bike and 2x BMX bikes through my entire season. It’s possible to take that trainer time and use it just about anyway possible. May not be “ideal” for people aiming to tweak out every last ounce from their training, but I think it’s more than adequate for the bulk of us around here.

My may reason for the question was to see if might be fit related in the sense that some have no issues outside on a bike but have problems on that same bike when put on a trainer. Not your case here.

That said, fit could still be a consideration so at least keep that in mind with respect to saddle setup and such. But I think the difference in your power & cadence is potentially the greater issue unless you are marginal on your trainer bike fit. That and the bulk of the other stuff you mention that I am not adept enough to address.

Hopefully you can figure it out. So what happens if you do high cadence in an easy gear (low power)? Does it still aggravate your knee?

It seems like the issue could be one or both of:

  1. High power = more force = more muscular load
  2. High cadence = less flexion control (poor tracking)

Again, I’m curious to know if your knee hurts when doing high cadence spin ups at a low relative power. If it doesn’t, then I would think that it’s the power (force), not the cadence that is causing the issue.

Irregardless, I don’t think it’s bad advice to tell you to keep working on hip and glute strength. Also adductor and abductor strength. Basically the muscles above the knee that can significantly impact how the knee tracks. For me it was very weak gluteus medius muscles.

Bottom line, don’t stop riding if you can do it in a way that doesn’t make your pain worse. Ultimately you want to be able to ride so it’s important to keep doing that.

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Thanks for your so much for your input. I’ve been assessing and the knee pain is present at all high cadences, whether high or low power. So I’m thinking technique.

I’ve also been paying more attention to the difference between my outside (on the mtbs) and inside stuff (on the roadie). I have much more glute activation and use on the mtbs, although I do use my glutes inside at lower cadences.

I can work on these things. :slight_smile: