Does a bike fit really “fix” your pedal stroke?

I got an e-mail from a blog reader recently about his experience with a bike fit. I want to say up front that this guy has a really good perspective on the whole thing and that our exchange was very beneficial. However, he did bring up some good points about a bike fit that I had not really thought about before.

He basically pointed out how, during the process of the bike fit, he was told that his knees caved in with each pedal stroke and his pelvis was rotated forward. Through the use of arch supports, shims and some other adjustments this problem was “fixed” and his legs now move much more efficiently, which resulted in more power and comfort while riding (I also need to point out that this was mostly on his road bike).

This got me thinking about how the problems were not really “fixed” and how a bike fit may actually be masking your real problems and setting you up for more pain down the road. Here is my take on bike fittings…

It really depends on how much you are in the saddle. A bike fit centers around you being in the seated position and as soon as you stand up the “fit” goes out the window. I know that stem length and bike size play a role and those things will stay the same but the majority of a fit centers on the getting you butt in the right position when seated.

So, if you are a roadie it is critical. If you are a mountain biker that tends to sit a lot then it is beneficial as well. However, for a rider who tends to stand a lot (around here the trails are really technical and you have to stand up a lot) a fit is not nearly as valuable.

Personally, I think most riders tend to sit too much (and the skills coaches I have spoken with agree) so while it is valuable, it is more valuable for some riders and less valuable for others.

Now, I also have to point out that all of the problems that were solved with your fit could also be fixed with corrective strength training. Your knees caving in is not from a bad fit, it is from your glute medias not firing properly which causes your femur to internally rotate and cause your knees to cave in. What happened was that the fit, shims and sole inserts masked that functional movement issue, not cure your pedaling problems. Yes, you are now pedaling in a more efficient position but I can guarantee you that some sort of problem will pop up down the road because you did not really fix the true problem, you put a patch on it.

However, that is the common approach to movement issues because most people do not understand movement or how to fix it. Those issues you identified in your fitting don’t just exist on your bike – they exist in everything you do. The bike fit helped you on the bike but what about all of the stuff you do off of it? Every time you run, jump, walk, bend down to pick something up or any one of a thousand other things those same issues are there and causing problems.

So, as you can see I am not anti-bike fit but I do think that it tends to get overplayed for mountain bikers (since they should be standing more on the trail) and that it masks problems instead of really solving the underlying issues. I want people to be better riders but I also want them to be better, more pain free human beings off the bike. The mobility and corrective type stuff I recommend will help you actually fix the problem.

Let me know what your thoughts are…

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  1. electric says:

    I have found that entering the world of bike fitting is a strange place where millimeters seem to matter a lot more than in everyday life. Not to say I haven’t uncovered a few facts that seem important to my comfort. Facts such as appropriate saddle height, saddle tilt and saddle setback(distance off vertical from BB). I was far too low, tilted too far down and setback too far. It didn’t seem to matter much to me when riding mtb, since most of my time was out of the saddle. It started to matter more when i sat in the saddle on long road rides.

    Anyways, i have noticed some quirks about my pedaling style… heel rotation is one(rubbed paint off chainstays). I’m curious now about this gluteus medius muscle misfiring, how does one correct? I had read on a different site about a lower-back doctor who had found many of his patients suffered from misfiring abdominal muscles, such that the posterior ones would fire a few milliseconds before the anterior ones and this would cause disc compression.. sorry about my physiology language. Anyways he recommended doing specific core exercises.

    I found the article:

    Reply • March 1 at 8:24 pm
  2. Adolfo says:

    Jim, The great thing about your articles is that it gets me thinking. You mention most mtb riders spend too much time on the saddle, of course depending on the demands on the trail, but I question, what happens when you have previous knee injuries? Supposedly, according to doctors, standing on an MTB, puts too much pressure on the whole articulation and may cause further damage (assuming the bike frame and fit are alright). What is your opinion? I suppose you will recommend strengthening the muscles that support the knee, which exercises are best?


    Reply • March 1 at 8:46 pm
  3. Ole says:

    Thank James for another thought provoking article. I too am interested in the glute misfiring thing. I had my knees caving in and the heel rubbins chainstay thing.

    This winter Ive done a lot of your BB-drills and lots of exercises at home like the single leg deadlift and core stuff: Im happy to say that Ive doubled the weight I can do on the single leg deadlift 🙂 (not very impressive 25 kg)

    So maybe the problem with knees caving in will be less this season. I wont know till the snow melts.

    Anyhow. Any specific drills to emphesize to stop knees caving in and heel rub?

    Regards Ole

    Reply • March 2 at 4:40 am
  4. bikejames says:

    I’ll do a blog post soon on the glute medias but in the meantime you can look up exercises like banded side steps and clam shells to get some ideas.

    @ Adolfo – as long as you are being told that you can not run or jump for the same reasons there may be something there. If not, I’d get a second opinion. Exercise that will help that are single leg squats, Bulgarian split squats and swings, among many others. Getting the leg strong and teaching it how to absorb impacts with the muscles instead of the joints is what you want to do.

    Reply • March 2 at 6:52 am
  5. Ole says:

    Thanks James…

    Reply • March 3 at 6:21 am
  6. Adolfo says:

    Thanks James, I was actually suggested not to run too much, to cause stress on the kness, so I try nordic walk instead and mtb. I´ll follow your advise and incorporate these exercises to a greater extent

    Reply • March 3 at 11:11 am
  7. electric says:


    How about using old spare-tubes for the clam-step and banded side steps instead of those elastic bands? Might be a good tip… you can also lock them valve side in between a door and frame for a hip adductor exercise

    Reply • March 3 at 7:55 pm
  8. Ken says:

    Agreed 10000%.

    I used to have knee problems and couldn’t ride more than 30k or 1hr – which ever came 1st. I played with cleat position (in / out), seat position (up, down, forward, back), bar height, stem length and each change made things better but only for a while.

    After a bike fit, 2 physios and almost 10 years of just dealing with the problem, I found a physio who diagnosed my problem as poor glute and VMO activation. We worked for about 6 months on the problem before I could ride as much as I wanted. It took lots of training (both on and off the bike) but now I can ride as much as I want with NO knee pain.

    Now, bike fit doesn’t seem to matter as much – I can feel if the seat/stem/bar is in the wrong position, but only because I’m not using my muscles (gluts, VMO, quads) properly.

    That’s my experience anyway…

    Reply • March 5 at 10:35 pm
  9. Jowee says:

    This is a good discussion to have. One that will benefit some people. I have built a few bikes for myself and others (mainly mountain (HT and full sus) but some commuters, the odd road bike and some real monstrous hybid frankenbikes too) and I am an *insatiable* tweaker. I believe in bike fit. One can see how important it is just by the fact that freeriders and hard trail riders change out their long XC stems for shorter ones. This is a practical move, but it inevitably alters the FIT of the bike. So even when not thinking about FIT specifically, these riders are changing it and they are doing so because they deem it to be critically important to their ride – even if they stand up most of the time.
    Some people use only one all mountain machine. They will put a longer stem and lower bars on it for epic rides and when they take it to a resort or park they slap on some riser bars and a short but stronger stem. They are dynamically adapting the fit of their bike to suit its purpose.
    So that is the next thing that needs to be considered. For people that live in real mountains, the fit can and will be different than if that same person and same bike were living in flat-land. In parallel universe #1 (mountains) the rider will likely have a shorter stem and perhaps some bar-ends so they can climb hard, but descend steep stuff too.
    In parallel universe #2, the same person and bike will likely be more stretched for speed on the less steep grades.
    Now relating specifically to knees. Fit is not just about saddle position. Do not forget crank length, or indeed the interplay between the two.
    You can have longer cranks with the seat farther forward and still keep the knee above the pedal axle. Whether this would be a good thing or bad would depend on many factors. But it WOULD be EITHER good OR bad. Not neither.
    One position and crank length would v likely be better (inverted commas) than the other for that rider on that bike on the trails used. So, I say, tweak away. If you do not, you will never find the sweet spot unless you are v lucky. Moreover, you will never understand the differences tweaking can make. And it can make really important differences. Just a 1cm difference in stem length can make the dif between cleaning gnarly climbs and falling off the back or spinning up. Just as tires selection makes the world of difference to performance. So does body position and that means fit. I sympathise with all riders insomuch that there are many variables and they are often v expensive to experiment with. But, once you have done it and understand what works best for you in each situation, you will be a better rider. Well, you wont actually be a better rider, but you will ride better! Get me! Lol.
    Tweaking can only go on so long with any bike before you find perfection on it. At that point, you know it is as good as it can be and then you really love it. But you MUST tweak to get there. Otherwise, you may well be (are likely to be) riding something that could be way off what it could and should be. That can lead to stress injuries, or even crash injuries too. But tweaking is beyond the reach of most riders (need tools, lots of free time, plenty of cash, a high boredom threshold…). Most shops can never tweak someone ELSEs bike anyway, even if they gave you a good many hours free. Only doing it yourself can get it right. That requires a lot of reading, thinking etc. There are plenty of resources to help get the process started. Like this discussion. And Sheldon Brown (bless him) can help anyone achieve the rest. My bikes would not be the PERFECT shredding machines they are if it were not for him. IMO, you cannot be a great rider without having spent plenty of time on his site and of course the review sites/forums to find out what others are doing and relate it to your own needs/problems and setup. TWEAK AWAY – for a better ride.

    Reply • July 17 at 10:36 pm
    • bikejames says:

      @ Jowee – Good insights, however I’m not sure I totally agree with all of them but that is what makes for interesting discussion. Personally I think that a traditional bike fit comes from a road riders perspective of efficiency, where is a mountain bikers fit should be with balance and technical skills in mind. Mountain bikers should also stand way more than roadies do and a bike fit is made in the seated position so when you stand the “fit” is gone. I don’t consider experimenting with stem length and crank length a “bike fit”, so maybe we are not comparing the same thing. I think that tweaking is fine, just a traditional fit has very limited application for real mountain biking (not to be confused with road riding on dirt).

      Reply • July 19 at 10:15 am

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