Proper Leg Extension Question vs. Modern....?
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  1. #1
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    Proper Leg Extension Question vs. Modern....?

    sorry if this isn't the correct forum for this, but after watching the last few pro tours, I couldn't help but notice a trend in low seat/less leg extension among all the pro riders. They seem so low with their knees maybe reaching 45 degrees. Is this just me or is this a new take on proper set up? I can't imagine they do it for any other reason than it being more efficient, powerful, etc.

    I come from the leg slightly bent, drop a plumb line from your knee to intersect the pedal shaft. anyone have some info on this or at least a theory?

  2. #2
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    If you look a little closer, you'll see every rider is a little different. Some have fuller extension and some have less (like Boonen). They are setup this way because this is how they feel comfortable or generate the most power.

    KOPS (knee over pedals) being an end-all be-all method of fitting was disproven quite some time ago. Everyone is a little different.

  3. #3
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    interesting. i'm getting closer and closer to going in and paying for a set up analysis.

  4. #4
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    If you don't know what you're doing, it'll be money well spent. Pay attention. I know I learned a lot. I don't know that I'd do it again, knowing what I know now, but I learned much of it getting a fit done.

  5. #5
    wim
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    Some thoughts.

    Quote Originally Posted by boleiro
    I couldn't help but notice a trend in low seat/less leg extension among all the pro riders. They seem so low with their knees maybe reaching 45 degrees. Is this just me or is this a new take on proper set up?
    A knee angle of 45 degress at bottom dead center would be considered very low even for a pro road rider. But your observation is correct: many (but not all) pros ride lower, and some much lower, than a recreational rider would. Part of the reason is simply that many recreational riders ride too high, making the pros look "low." Why that is so is open to speculation, but a good guess would be the proliferation of bad or nebulous saddle height advice in popular literature ("knee almost straight," "proper leg extension," "raise the saddle until the hips rock, then lower a bit," and such stuff.)

    Another thing to consider is how you're watching the pros. It's a fact that a video of someone pedaling a bicycle at normal road cadences will always show that rider with much more of a knee angle (like your 45 degrees) at what appears to be bottom dead center than it is in actuality. Not sure why this is so, but it's definitely true. If you doubt it, video yourself on a trainer at 80 rpm or higher and be amazed how "low" you look. Then advance the clip frame-by-frame and see how your knee angle looks normal again on the frame that shows your foot at bottom dead center.

  6. #6
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    Some basic fit guidelines.

    A fitting is not needed. Especially one you have to pay for.
    Heres what you do:

    Position cleats so a little extra foot is on top of the pedal. Set saddle height so your heel just grazes the pedal at bottom of the pedal stroke. Set the seat for/aft so plumb line puts your knee 1-2cm behind the pedal spindle.
    This is the power position.

    tweak this position by putting the bike on a computrainer and measuring wattage for a given heart rate.
    Lots of time(some of it aerobically agonizing) is spent on the tweaking process by pro/Cat1's who are fortunate enough to have a kinesiologist on the payroll.

  7. #7
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    Three standards with long running success:

    .883 x true inseam. Applied between BB spindle and saddle top along the angle of the seat tube.

    1.09 x true inseam. Applied between the pedal spindle at the bottom of the stroke and saddle top along the angle of the seat tube.

    Using a goniometer, setting 25 to 30 degrees leg bend at the bottom of the pedal stroke.


    All of these are time proven to reduce knee strain and be efficient. They are all usually a bit higher than the straightleg method.

  8. #8
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    I've tried both fitting techniques by rx-79g and bicyclemech1 and they put me scarily close to the same saddle height. in all cases, its just under 2 inches below my current saddle level. I'll give it a go tomorrow and see how it feels. cool how that all pretty much landed me at the same level?

    thanks for the help.

  9. #9
    Bianchi-Campagnolo
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    Almost 2"? Whoah, that's a stretch!

  10. #10
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    yeah, exactly what I thought. So, I'll give it a go tomorrow and see how it feels. Its seems really low but thats why I started this thread since all the pros seem so low. We'll see. Hell, I might have even implemented the advice above incorrectly.

  11. #11
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    Don't be a toe pointer!
    Lots of riders spin around like they wearing stripper heals. Drop your heel, spin smooth circles and unleash the power of large muscle groups

  12. #12
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    try this...

    Try adjusting the saddle height so the foot is horizontal with the leg fully extended at the bottom of the stroke. During normal pedaling, it will require a 2-3cm rise of the heel to create the commonly recommended 30 degree bend at the knee.

    If you feel pulling at the back of the knee or hamstring, it probably means that you don't normally pedal with that much heel rise. If it feels low, then you might try that setting for awhile to see how it feels.

    This method automatically take into account your pedal and shoe stack height. Formulas and the heel on the pedal method don't.

    The problem with static devices like a goniometer, is that you don't really know what your normal foot angle is. If the 30 degree bend at the knee is measured with the foot horizontal, then pedaling with very much heel rise would create far too much bend at the knee.

  13. #13
    wim
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    Quote Originally Posted by C-40
    Try adjusting the saddle height so the foot is horizontal with the leg fully extended at the bottom of the stroke. During normal pedaling, it will require a 2-3cm rise of the heel to create the commonly recommended 30 degree bend at the knee..
    This has worked really well for me, especially in preventing a saddle too high with the resulting and very noticeable loss in power. Keep in mind that there needs to be some flexibility left in your leg muscles and tendons around bottom dead center of the crank circle. You're cycling, not pushing a power boat away from the dock with your legs. Disagree with the toe pointer comment. IMO, just do what comes naturally when it comes to ankle flexion.

  14. #14
    Ride bicycles? Why?
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    Quote Originally Posted by C-40
    The problem with static devices like a goniometer, is that you don't really know what your normal foot angle is. If the 30 degree bend at the knee is measured with the foot horizontal, then pedaling with very much heel rise would create far too much bend at the knee.
    This is why it pays to have a flexability test done first. Too many riders are over-extending and putting too much stress on their bodies.

  15. #15
    wim
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    Quote Originally Posted by zach.scofield
    This is why it pays to have a flexability test done first. Too many riders are over-extending and putting too much stress on their bodies.
    Agree with what you say, but C-40s "too much bend at the knee" = under-extending = too low.

  16. #16
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    Quote Originally Posted by zach.scofield
    This is why it pays to have a flexability test done first. Too many riders are over-extending and putting too much stress on their bodies.
    I would say that's pretty rare. Most people are too low.

    The easy way to tell if you're too high is to ask someone who's riding behind you. If you're too high your hips will rock as you pedal.

  17. #17
    wim
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    Quote Originally Posted by rx-79g
    I would say that's pretty rare. Most people are too low.
    Shows you how perceptions, localities and opinions differ: many people around here are too high.

  18. #18
    orlin03
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    Quote Originally Posted by bicyclemech1
    Don't be a toe pointer!
    Lots of riders spin around like they wearing stripper heals. Drop your heel, spin smooth circles and unleash the power of large muscle groups
    This led to a huge improvement for me, as well as a huge drop in my seat height. When I finally went in for a detailed fitting (basically spent all day at Elite in Philadelphia), Dave stressed the importance of keeping the heel low, and I ended up with a pronounced drop in saddle height. This was right before going into the most intensive training of my career, and when the intervals reached ridiculous status, keeping my heels down was the only way I was able to remain at the intensities I was striving for throughout the set and still keep my cadence in the right range.

  19. #19
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    And many people around here are too high, too low, too far back or too far forward.

    But brake hoods normally are too low, which is sort of like an inversion of the US Fred setup.

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