Knee pain on flats, not hills or muni

My unicycling has been limited over the last several years due to knee pain under the center of the knee cap. I’ve been treating it with flexibility exercises with mixed success. However, I find muni and hilly rides to be much more friendly to my knees than flat easy rides. Based upon everything I have read most people with knee pain have the opposite experience. I have had to deal with knee pain on muni rides but it seems to respond better to stretching. I should add that I use a KH 29’er with 150mm cranks for my muni rides and I use a Nimbus 29’er with 110mm cranks for my flat and hilly pavement rides. It doesn’t seem to be related to the change of unicycle since my knees like hilly rides with the 110 cranks.

Has anyone else had a similar experience?

I have very similar problems. I think.

My ride for the last two years was a 29" Oracle with 150’s.
Several times I swapped out my 138’s and very quickly developed knee pains. They went away when I swapped back to 150’s.

I just bought a KH29 and the stock 31" diameter of the Duro “Crux” caused a little discomfort in my knees. I now run a 30" Maxx Minion with no discomfort.

I’ve also tried the 127 holes in my cranks and could really feel it in the knees.

So I’ve settled on a 30" tire and 150 cranks and no pain whatsoever.
I’m guessing the large number leap is too much for my weak knees. I’ll ride with this and try changing something when my knees and technique are stronger.

With muni you’re also standing up lot and that is a welcome break for your knees. Riding street this doesn’t happen.

Once I lowered the saddle of my g36 for a muni ride. For whatever reason later on the street I didn’t put it as high. This was a great improvement in regards of knee pain. So try having the seat 0,5cm lower than you think what is the optimum.

Engage the buttocks…
When on the flat you don’t engage your buttocks. When you work harder doing muni your buttocks have to work harder. Over worked quads cause knee pain.
Doing squats can train your buttocks to work harder. There are
Quite a few articles on the internet about it.

Hope this is useful. Stew

Not at all an expert since I haven’t experienced chondromalacia myself but I know a little from running pals who’ve been through it, and that seems like good advice if you have a particular spot of inflamed cartilage.

The larger range of motion with your muni cranks might be spreading the work over a larger area instead of staying right on that irritated spot, or there could be some better self-lubricating action going on.

A quick search turned up this page which looked pretty good:

Assuming that cartilage is like ligaments and tendons and other tissues with little blood flow and not much metabolism, not doing the thing that aggravates is a good first step. Stretching the muscles the affect it might help a little but doesn’t do anything for connective tissue itself. A big thing is to be patient and anticipate it probably taking months rather than days or weeks to get better, sometimes years if ever to really be right again. Good luck with it.

I’ll have to give this a try. When I ride on pavement I do keep the seat quite high but strangely enough not when riding hilly terrain. In the past I’ve found that a 36’er wheel with 125 cranks is friendlier to my knee on flat terrain that an 29’er with 100 cranks.

I recently got a plyo box to do one-legged squats. The tricky thing is that I’m currently riding 3 days a week of muni (45 minutes - 1 hour) and that leaves my legs too tired to recover from squats. Perhaps I need to reduce my riding. On the upside my knees have been good to me the past month so my stretching routines seem to be helping. I still long for the time when I could go on 4 hour muni rides.

I’ve not pesonally really experienced this, but it seems to me that the 2 most likely things have been mentioned:

  1. seat height
  2. short canks causing increased forces and/or different muscles involved.

It wasn’t really a problem for me, but I did develop some isses from road 36 with 100mm cranks because the muscles necessary for unicycling were way different. My IT-band along the outside of my legs was really getting overworked, which I think was from a much smaller range of motion also requiring muscles other than the large quads/thighs to produce lots of the torque.

Now that I’ve been riding with longer cranks (mainly as my 100-120km/week of commuting have been reduced to 1.5km/direction but also because I’ve been riding my new KH29+ more offroad - with 150mm cranks) my IT band problem has pretty much disappeared.

It is strange that the pain is not on hills as that is when the forces should be the highest… which maybe points to the seat height as the issue. That should be pretty easy to test by simply reducing your saddle height for a few weeks.

When I first got my 29’er I rode it with 125mm cranks. When my knees started bothering my on flat easy rides I switched to 110mm and later 100mm. The shorter cranks allowed me to ride a bit longer before the knee started giving my grief. It didn’t completely solve the problem but it allowed me to ride a little longer without pain. The 36’er with 125mm cranks seemed to be friendliest to my knees but I can’t say for sure since I don’t own a 36’er and I’ve only ridden one about a dozen times.

I suffered from ITB syndrome on the left knee, back in 2015.
I managed to understand how to fix it once for all : lowering the seat height (on all my unis) so that the distance between the seat and the low pedal was never higher than 82cm in my case.(about 83 if I have five tens shoes).

Since then I never encountered this issue anymore, but I had to deal with another kind of pain, still on the left knee but a more patellar kinda pain.
I feel this pain especially when I ride a geared unicycle or a 36er (or both now)

If I want to minimize my chances to feel this pain during a ride, all the more so as I rather ride a 36er and a G36, I have to warm my knees before each ride.
I do some kind of progressive squats and one leg squats, with a lot of low movements and a bit of stretching (I stretch one knee while I do one legged squat with the other leg).
It works pretty well.
I also have to be careful with my pedal stroke: it has to be light and easy, if it’s hard this often means that my other leg (upstroke) is fighting against the down stroke by resisting, or that I’m not leaning forward enough to let the gravity help me (unicycle is a perpetual fall forward process, right? we can use it to decrease the needed torque).

Strangely I 'm also ok with uphills, but I try to think “raise the legs” rather than “push downward”.

I also think that short cranks are more likely to bring knees/tendons issues than longer cranks because of the higher torque required and because a restricted part of leg muscles are doing the job.
It’s ok when the speed is high and constant but at low speed, on complicated situations, on uphills, after each freemount, each time you have to accelerate or slow down, short cranks must be a nightmare for the knees and the muscles/tendons involved compared to long cranks.

Try doing some deep jumping squats just before you ride and a few when you finish your ride. It will “fire up” your buttocks and relax your quads. Ensure that when you extend you push your hips out to fully engage your buttocks.


I have a very similar experience. I alternate muni between a 29" with 150/127 (set at 150) and a 24" muni with 150’s. I almost never have problems with muni, but do with road riding, and it seems to come on much faster with the 29" with and pedals at the 127 hole. Same pain you describe, behind the knee cap. Very frustrating.

Doc took x-rays etc. and did not see any bad issues. PT helped, see attachment, but still had problems road riding more than an hour especially with the 127’s.

My final conclusion is that I should ride with the 150’s on the 29’re and if I take a couple of ibuprofens before I ride, I don’t have problems for the duration of my typical ride (usually 45 min to an hour, 2 hours at most).

Hope this helps and good luck! Knee pain can be really frustrating!

knee PT.pdf (361 KB)

Several months ago I started taking a brisk 10 minute walk before my rides and I’ve definitely had more success. The only time I had a problem was when I rode an easy route and I warmed up by doing body weight squats instead of my walk. A few days ago I returned to my easy route and I did a 15 minute warm up walk and I did not have any knee pain. I was planning on lowering my seat about 1/2 inch but I forgot my tools so I’ll try that as well next time. In any case it does seem that a warmup is crucial. Of course I’ve been working hard on my flexibility as well so it is always hard to figure out what helped.

In any case I’m not ready to declare victory just yet. In the past I’ve had several good months without knee pain and then it comes back again. I need at least 6 months of success before I can declare victory.

I’m also wondering if a high cadence is part of the issue. I need to get back to some tougher trails that I’ve been avoiding for quite a while and see how my knee responds.

Thanks to all for the good suggestions. This is still a work in progress and hopefully other riders will get some relief from these suggestions.

Very interesting thread.
I’ll add my 2cts. Once I could ride my unicycle, I spent a lot of time taking it to the local forest, going on trails. Each time I would hit a tarmac section, it would suck, but I blamed it on the low pressure knobby tire.

And then I realized I was not riding properly. Having spent too much time on trails, I integrated bad habits, number one being that I wasn’t putting all my weight in the saddle. Which is fine off road because you’re always alternating moments: a few seconds in the saddle, then a root or a dip makes you stand even slightly, then you seat until the patch of mud and so on. I had become pretty good at riding with more weight on the pedals than on the saddle.

I probably did that for a good 3 years, so it became really ingrained in my riding. But my knee never hurt.

When I got a 29", I started using it the same way. The forest here is pretty flat, so a bigger wheel was still appropriate. But it made me want to use it in town. And that became more exhausting. I slowly realized that there was something wrong with my riding. I always had slightly too much weight on my pedals as it was the only way I knew how to control the thing. But unlike off-road riding where there were alternating moments: it was constant. And I started developing a pain in the right (dominant) knee. To the point that after some rides, going down a staircase was really painful. For the past two years, I’ve been working on changing my bad habits and relearning. I’m getting much better, but the weight on the pedal reflex is still lurking, ready to push out the newly acquired technique. So when I start to get tired, or get in a stressful situation (big camber ahead, lots of people on the sidewalk), it takes over. And the knee pain creeps in.

Each ride allows me to get better at this, I haven’t had lasting pain for a while, but it feels like the knee has become fragile. Maybe from all the rubbing/grinding it got because of the weight plus movement. Talked to my physiotherapist and there’s no evidence, the knee seems to work properly. Just have to continue relearning until my feet are light as a feather!