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Old 03-25-2017, 04:38 PM
Grumbs Grumbs is offline
Join Date: Feb 2011
Posts: 51
Originally Posted by fuzzalow View Post
OK and with equal respect I'll simply accept you at your word about this. I'd like to see an example someday as to what this limitation does and its effect. In fact, I'd like to see the entire position on the bike to see if indeed the hamstring is the limitation or if that "tight hamstring" is the accepted blame for the limitation.

This is the side view:

Yes the hamstring must allow the pelvis to pivot further forwards and still complete a range of motion for a pedal stroke. But the hamstring is tiny in relation to all of the other muscles used in cycling. And yet this muscle is the one often given as making riding a racebike impossible.

Surely such a pronounced limitation must impact movements in living a normal life - like bending over to pick up a dropped pen. I am not disputing you, I am trying to make sense of this as, for me, the biomechanics don't add up. No reply necessary, I felt compelled to rebut because this oft-given excuse is way outta left field for me.
Limited ROM in this area does impact movements in living a normal life. But in normal life its easier for people's bodies to compensate in various ways. Mostly, when picking up a pen, people will bend at their back instead of their hips, or -- if they have to crouch -- they will adduct and internally rotate their femurs because there isn't enough slack in the hamstring to bend straight at the knee and hip.

On a bike it's harder to compensate like this, because you have parts of your body set in fixed positions. Pelvis fixed on the saddle is the most difficult to get around.

All you have to do to figure this out is imagine yourself with a really tight hamstring, then try to repeat your habitual movements and see where you compensate.
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Old 06-16-2017, 06:12 PM
asiantrick asiantrick is offline
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Old 07-07-2017, 10:17 PM
Pastashop Pastashop is offline
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Join Date: May 2004
Posts: 1,077
Interesting discussion...

For what it's worth, I'm 6' tall and am comfortable riding 57-60 cm frames with 57 cm up to ~58.5 cm top tubes, provided the frame has a slack seat tube... but a lot of adjustment can be obtained via the stem / bar / brake lever combo, obviously.

To the OP's original intent, it seems like getting into an "aero" position is not a limitation for the OP. This often begets a longer top tube than for less flexible folks, all other things being constant. LeMond bikes tend to have top tubes on the longer side for a given frame size. A 55.5 cm LeMond frame would produce a rather short seat tube and quite a bit of saddle to bar drop, no?
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