Cycling "knock knees"??

[Melstar]

I just realized something.

I was having a ride the other day and i noticed when i was viewing from behind (I was cycling behind my friend), that my partner cycled with her knees sometimes tilted medially ie towards the bike frame...something like knockkneesm except on a bike.

When i mentioned it to her, she said that I was doing it to.

Anyone knows what i'm talking about, and any idea if its just an illusion or a bad cycling habit?

erin

[Kalidurga]

If you watch pro bike races, you'll notice that most of the pros ride that way, too. I haven't really researched it so I can't explain it, but I assume it has to do with which thigh muscles are used depending on how the leg is positioned. Generally, the adductors on the inside of the thigh are weaker than the abductors along the outside. Pedaling with the knees pointing out, which I see fairly frequently on the bike trail, pulls the adductors into play and puts the knee in a stressful position. It's an inefficient position. Pointing the knees slightly in toward the top tube, though, brings all of the more powerful quad and abductor muscles into play and keeps the knees in a safer position. Much more efficient and powerful for pedaling. Plus, pulling the thighs toward each other that way will eventually help to strengthen the weaker adductors a bit.

That's all my own speculation based on what little I know of anatomy, though. I could be totally off-base.

[7rider]

Kali,
That's actually consistent with what I've read - when pedalling you should nearly brush the top tube of your bike with your knees. The more efficient pedal stroke you describe would pretty much do that.

[Snicklefritz]

I think the position you describe is also more aero. In fact, I was reading an article in one of the cycling magazines that referred to a new bike design that one of the pro teams was involved with. Apparently these new bikes were built so that the riders knees would be brought closer to the top tube, helping to reduce frontal area.

[KnottedYet]

"Sometimes tilted medially" (which I'm assuming means sometimes NOT?)

We spend a lot of time training athletes NOT to do that. Especially women. Strengthening their hip external rotators to stabilize the femur, so the knee tracks properly through the entire motion.

If your knee is tracking straight up and down as you pedal, life is good regardless of how close your knee is to the top tube. I've seen some pretty funny looking knee postions, but the rider's knee joint is tracking straight without generating medial-lateral stress so we don't change a thing. Everyone is built differently.

If the knee is wobbling left or right toward or away from the bike, or making little swoops (as viewed from the front), you are setting yourself up for trouble regardless of where your knee is relative to the top tube.

A lot of that is also the function of the foot mechanics. The loading pattern for the foot/ankle is vastly different walking vs pedalling. You can have wildly expensive cycling-specific custom orthotics made, or you can buy Specialized Body Geometry shoes (which Andy Pruitt had a hand in) which are already posted medially in the forefoot. That's in the shoe, rather than in the insole, so you can switch out the insoles without losing the posting. (most folks can be corrected with a simple posting, but don't rule out orthotics if you really need them)

Be kind to your knees! Pretend they are a simple hinge, and try to minimize any twisting going through them, whether the "twist" is initiated at the hip or the foot. (we usually work on the entire leg, pelvis, and the lower abs)

Mind you, I'm not saying anything about where the knee hangs out relative to the top tube. I'm talking about knees that CHANGE POSTION through the stroke relative to the bike frame. Melstar said "sometimes tilted medially" and it was the word "sometimes" that got my attention.

[aicabsolut]

If you watch pro bike races, you'll notice that most of the pros ride that way, too. I haven't really researched it so I can't explain it, but I assume it has to do with which thigh muscles are used depending on how the leg is positioned. Generally, the adductors on the inside of the thigh are weaker than the abductors along the outside. Pedaling with the knees pointing out, which I see fairly frequently on the bike trail, pulls the adductors into play and puts the knee in a stressful position. It's an inefficient position. Pointing the knees slightly in toward the top tube, though, brings all of the more powerful quad and abductor muscles into play and keeps the knees in a safer position. Much more efficient and powerful for pedaling. Plus, pulling the thighs toward each other that way will eventually help to strengthen the weaker adductors a bit.

That's all my own speculation based on what little I know of anatomy, though. I could be totally off-base.

Knee-in position actually works the adductors more, not the abductors, as the abductors work to pull the knee in outward rotation from the hip. My inner thighs are infinitely stronger than my outer, from riding horses, and in a hard effort, I'll enlist those muscles more and my knees might come a little closer to the top tube, toes floating out slightly. I also know this is the case because my right leg has a bit of a curve in it--slightly bowed. Even with body geometry help, it still tracks more knee-in than the other. And if I'm not careful, I'll strain one of the longer groin muscles--the one that runs right next to the inner ham. Clearly overusing the adductors, not the abductors. Knee-in might pull on a tight ITB, but it's not enlisting those abductors more than normal.

[spokewench]

I've been riding for about 20 years - have a hitch (what I call it in my right leg) where my right leg (knee) dips towards the top tube. It gets worse when I'm tired. I've always attributed it to the fact that I have crushed vertebrae in my lower back and compensate for that.

So far, no knee pain - so I'm not sure about the theory that this is going to cause trouble in all people.

[aicabsolut]

Yep, I agree.

I should've added that my right knee tracking in is a biomechanical thing--not that the left one is way out, but it's straighter--and while I've got a host of issues with my right side, the knee is definitely not one of them.

[CR400]

Actually riding with your knees in toward the top tube is the natural position for your legs, especially for us women with wider hips. Unless a person has a problem with bowlegedness no matter how slight they will ride with their knees pointed in to some degree. I have read that it is actually a bad riding position to Not have your knees in at least slightly. It is not only not aero but it is also anatomically less efficient.

[Kalidurga]

Knee-in position actually works the adductors more, not the abductors, as the abductors work to pull the knee in outward rotation from the hip... Knee-in might pull on a tight ITB, but it's not enlisting those abductors more than normal.

Thanks for the correction, aic-fan, that does make more sense now that I think about it.

I'm just amazed at the number of people I see riding with their knees sticking out like little wings on the side of their bike. When it's an older couple cruising slowly on touring bikes, it's one thing. When it's some guy on a fancy road bike in full spandex kit and gear, I just want to stop him, smack him on the knee, and say "Tuck those suckers in, dude!".

[KnottedYet]

I've been riding for about 20 years - have a hitch (what I call it in my right leg) where my right leg (knee) dips towards the top tube. It gets worse when I'm tired. I've always attributed it to the fact that I have crushed vertebrae in my lower back and compensate for that.

So far, no knee pain - so I'm not sure about the theory that this is going to cause trouble in all people.

Yep, I agree.

I should've added that my right knee tracking in is a biomechanical thing--not that the left one is way out, but it's straighter--and while I've got a host of issues with my right side, the knee is definitely not one of them.

If your joints are happy and you aren't generating medial/lateral stress, life is good. Like I said, I've seen some pretty wild knees and some pretty interesting compensations, but if they are tracking straight (femur relative to tibia) we don't try to change anything in the clinic.

Legitimate biomechanical compensations are exactly that, and shouldn't be changed.

However, if someone doesn't already have something they are correcting for, and they find their knee is wobbling due to a weakness or a force imbalance; they need to be aware of the stress they are putting through the structure.

I have seen plenty of sucessful knee replacements, but keeping your own knee healthy is usually a pretty good idea.

[RoadRaven]

Like its already been said - "knock knees" is desirable.

In my experience, many new cyclists tend to ride with their knees out - and so do many older cyclists.

That was certainly me, with one knee pointing more out than the other.

Getting my knees both pointing forward alleviated knee discomfort.

Getting my knees in the habit of pointing in to the frame has "disappeared" my knee pain and of course in a race situation, you become more aero.

Having knees pointed out, or even straight ahead creates a "bucket" which "catches" wind and slows you...

The most important thing is your comfort though... find the best way for you to ride and stick with it.

[velogirl]

Actually, I would say that neither knock-knees nor bow-legs are desirable, but they're very common with inexperienced riders (or more experienced riders who've never been taught how to pedal correctly).

Typically women are more knock-kneed; men are more bowlegged. The condition has to do with hip flexibility. Neither is an efficient way to ride because you see wasted motion in the pedal stroke. It takes time to correct the flexibility differences and track in a straight plane. While we don't want to "force" the pedal stroke (which causes stress on the ankles, knees, and hipe), we want to correct this within an acceptable range of motion for each individual.

[RoadRaven]

Sorry Velo... what I meant when I chimed in on the "knock knees", I was not referring to true 'diagnosed' knock knees...

I just meant that when you cycle, if you are aiming for aero position, you try and "aim" your knees inwards to reduce the bucket effect - in the same way aero bars reduce the bucket created on the tops or drops.

You are very right, Velo, you still want comfort for the rider and position should not compromise comfort.

[SouthernBelle]

Would properly positioned cleats, assuming your are riding clipless, help alleviate some of this?