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Bike seat positon and muscle recruitment?
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To start, I have read tons of stuff about bike fit, but I want to know what you all think is the best way to get a pretty decent fit (instructions please) without going to a professional because I don't have the money right now. I mean like the best way you have found to get a good reliable fore/aft position and proper height. Now, after that, can you please explain to me how adjustments in each direction (up, down, front, back) will effect which muscles are being used more or having more strain put on them? Thank you very much, any other comments about seat position and resulting injury would be great.
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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It can be hard to say, since things like body morphology, flexibility and simple preference influence how you sit. I would say that most people make the fit issue too complicated, you really want 3 things: to be comfortable, powerful and aerodynamic. Its not a bad thing to toy around with your position too, while you ride, just explore and get a sense of how to keep all of the 3 in balance. I can be very comfortable and powerful in an upright position but my aerodynamics suffer massively, so the key for me is trying to get as low as possible without impacted what I know are quality power numbers and my own perceived comfort level. It simply takes trial and error. One problem I see with fitting a person in 1 session is the fact that although your optimal position may feel a little off at first, you can adapt to it over time with practice.

If you want to do it yourself, I would highly recommend, or hope you already have a power meter, quantifying how powerful a position is based just on perception is not going to work, I have tried high saddle positions that 'feel' really strong but my power meter shows me I'm in fact putting out a lot less power than in lower positions. Personally, my optimal seat height is where I can sit in my aero position and put my heel on the actual pedal with a straight leg without leaning to that side. In terms of seat angle, I would say 85 degrees is a good place to start. One of the biggest issues for me is saddle tilt, I like the nose tilted up, takes weight off my arms and I don't feel like I'm slipping forward. As for the aerobars, thats where comfort just takes over, place them wherever they feel most comfortable, personally for me, I like an angle greater than 90 degrees, allows me to put some of the tension in my lats and relax more.

Without respect to fore/aft, seat height on its own mainly impacts glute vs quadricep activation, a higher seat means more quadricep activation. One reason my power numbers are lower at higher heights is that your glutes just can't contribute much when your leg reaches a certain extension. Basically you want a happy medium in height where you get the leverage from being at a reasonable height, but are able to use your quads and glutes together for maximum power, for me thats the height where I can place my heel firmly on the pedal without leaning.

Fore/aft adjustments in my experience also impact glute/quad activation and also hamstring activation. Without respect to height, a more rearward seat puts more effort into my quadriceps, whereas a steeper angle utilizes glutes more. When I raced road bikes at a much slacker geometry, I had massive quads, something that went away when I went steeper. Steeper geometries also seem to activate the hamstrings much more for me, but that also depends on how you pedal.

Overall, the complicated part is that fore/aft and seat height, working together, produce some interesting results. Additionally your pelvic tilt can have a massive difference on where you feel the effort. Like I said, with a power meter and some experimentation, you should be able to dial in a strong, comfortable and aero position in a few weeks.

If you can, post videos here of your position, posters here can help you with some of the finer details just be watching you ride.
Last edited by: HXB: Jan 24, 13 8:32
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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Seat Height can effect your actual for/aft, so raising your seat higher (too high) typically moves you more towards the front of you seat which will give you the same effect as correct seat height with saddle too far foward realative to front end...Seat forward will be more quad dominate if pelvis and front end aren't moved proportionately...

Futher back is more glutes.....unless your seat is (too low) then this too will feel pretty bad and may effect the quads disproportionetley...(more likely you just won't feel very powerful if you are too low)


When I fit myself a good starting point is puting your saddle in the postion listed above...Heels can touch pedals when leg is straight. I start this from a relatively slack postion (more slack then I will ride)

Assuming you are on the right size bike (and depending on saddle), but this will be a touch behind a neutral saddle position which would be dead center on the rails....but in any case start towards the rear with correct height...

Start off with a level seat (just lay a board across the top and make sure it is realatively flat)

get nice and warmed up and then find a little bit of a hill that you can ride up and down for about a min or two and a pretty strong effort...

Do it once at a high cadence then once at a lower cadence in a bigger gear...Move you seat up a little bit at a time and repeat the process...You should feel like you are pedaling in nice smooth circles without reaching for the pedals or feel like you are just mashing (stomping) on the pedals...once it feel a little too high like your reaching or the saddle is really jamming your stuff then go back down to last height...

This will give you optimal saddle height...now start moving it foward a little bit at a time...Go to a neutral postion and then to a steep postion, but make sure you adjust the height again at each fore/aft position...

When you move your seat foward it will have to go up again...Eventually you will get to a place that doens't feel good and you won't feel very powerful or your quads will burn disproportionetly.....

Once you find your most powerful/comfortable/stable saddle position then adjust your front end for comfort...This is the same process for a road or a tri....Tri bike is just going to allow you to rotate around the bottom bracket (steeper) more...

once you have your optimal postion dialed you can tweak the angle of your seat a little for even better comfort...Once you have this done spend a lot of time riding in this postion...and then worry about minor little tweaks and getting more areo later...

You really have to find your sweet spot and how your pelvis settles into your saddle before you can effectively start trying to ride in your steepest postion possible...


Couple things to watch out for....people sometimes don't have a comfortable saddle and end up moving there seat too far foward for a front end that is relatively high...you get crunched up and the pelvis is too vertical for seat tube angle...The tendancy here is to raise your saddle too high...don't do this...

If you follow the process above you don't need any measuring tools...I can tell you that you will measure very well.....


Now with that being said...If you don't know if you are on the right size bike...don't really know how to make adjustments and/or generally figure things out then you might want to consider a professional fit...

But it really isn't that hard.... The biggest issue that newbies run into is that they have a bike that is too big for them with respect to how low they are gonig to be able to get....(the bike is too long and they end up stretched out....)
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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Big wrote:
Seat Height can effect your actual for/aft, so raising your seat higher (too high) typically moves you more towards the front of you seat which will give you the same effect as correct seat height with saddle too far foward realative to front end...Seat forward will be more quad dominate if pelvis and front end aren't moved proportionately...

Futher back is more glutes.....unless your seat is (too low) then this too will feel pretty bad and may effect the quads disproportionetley...(more likely you just won't feel very powerful if you are too low)


When I fit myself a good starting point is puting your saddle in the postion listed above...Heels can touch pedals when leg is straight. I start this from a relatively slack postion (more slack then I will ride)

Assuming you are on the right size bike (and depending on saddle), but this will be a touch behind a neutral saddle position which would be dead center on the rails....but in any case start towards the rear with correct height...

Start off with a level seat (just lay a board across the top and make sure it is realatively flat)

get nice and warmed up and then find a little bit of a hill that you can ride up and down for about a min or two and a pretty strong effort...

Do it once at a high cadence then once at a lower cadence in a bigger gear...Move you seat up a little bit at a time and repeat the process...You should feel like you are pedaling in nice smooth circles without reaching for the pedals or feel like you are just mashing (stomping) on the pedals...once it feel a little too high like your reaching or the saddle is really jamming your stuff then go back down to last height...

This will give you optimal saddle height...now start moving it foward a little bit at a time...Go to a neutral postion and then to a steep postion, but make sure you adjust the height again at each fore/aft position...

When you move your seat foward it will have to go up again...Eventually you will get to a place that doens't feel good and you won't feel very powerful or your quads will burn disproportionetly.....

Once you find your most powerful/comfortable/stable saddle position then adjust your front end for comfort...This is the same process for a road or a tri....Tri bike is just going to allow you to rotate around the bottom bracket (steeper) more...

once you have your optimal postion dialed you can tweak the angle of your seat a little for even better comfort...Once you have this done spend a lot of time riding in this postion...and then worry about minor little tweaks and getting more areo later...

You really have to find your sweet spot and how your pelvis settles into your saddle before you can effectively start trying to ride in your steepest postion possible...


Couple things to watch out for....people sometimes don't have a comfortable saddle and end up moving there seat too far foward for a front end that is relatively high...you get crunched up and the pelvis is too vertical for seat tube angle...The tendancy here is to raise your saddle too high...don't do this...

If you follow the process above you don't need any measuring tools...I can tell you that you will measure very well.....


Now with that being said...If you don't know if you are on the right size bike...don't really know how to make adjustments and/or generally figure things out then you might want to consider a professional fit...

But it really isn't that hard.... The biggest issue that newbies run into is that they have a bike that is too big for them with respect to how low they are gonig to be able to get....(the bike is too long and they end up stretched out....)





BTW - if you want to feel which adjustments effect which muscles you can overexagerate your fit in either direction and your body will tell you right away...

Put your seat back to its furthest fore/aft postion...(make sure saddle isn't too high) and then get pretty low in the front (so bend at the waist (which will close your hip angle off)...and you will feel glutes big time (you won't be able to spin a cadence very well, but you will feel the leverage from pushing behind the bottom bracket).........Put your seat really far foward (all the way) and your will feel you quads burn....
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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Big wrote:
Big wrote:
Seat Height can effect your actual for/aft, so raising your seat higher (too high) typically moves you more towards the front of you seat which will give you the same effect as correct seat height with saddle too far foward realative to front end...Seat forward will be more quad dominate if pelvis and front end aren't moved proportionately...

Futher back is more glutes.....unless your seat is (too low) then this too will feel pretty bad and may effect the quads disproportionetley...(more likely you just won't feel very powerful if you are too low)


When I fit myself a good starting point is puting your saddle in the postion listed above...Heels can touch pedals when leg is straight. I start this from a relatively slack postion (more slack then I will ride)

Assuming you are on the right size bike (and depending on saddle), but this will be a touch behind a neutral saddle position which would be dead center on the rails....but in any case start towards the rear with correct height...

Start off with a level seat (just lay a board across the top and make sure it is realatively flat)

get nice and warmed up and then find a little bit of a hill that you can ride up and down for about a min or two and a pretty strong effort...

Do it once at a high cadence then once at a lower cadence in a bigger gear...Move you seat up a little bit at a time and repeat the process...You should feel like you are pedaling in nice smooth circles without reaching for the pedals or feel like you are just mashing (stomping) on the pedals...once it feel a little too high like your reaching or the saddle is really jamming your stuff then go back down to last height...

This will give you optimal saddle height...now start moving it foward a little bit at a time...Go to a neutral postion and then to a steep postion, but make sure you adjust the height again at each fore/aft position...

When you move your seat foward it will have to go up again...Eventually you will get to a place that doens't feel good and you won't feel very powerful or your quads will burn disproportionetly.....

Once you find your most powerful/comfortable/stable saddle position then adjust your front end for comfort...This is the same process for a road or a tri....Tri bike is just going to allow you to rotate around the bottom bracket (steeper) more...

once you have your optimal postion dialed you can tweak the angle of your seat a little for even better comfort...Once you have this done spend a lot of time riding in this postion...and then worry about minor little tweaks and getting more areo later...

You really have to find your sweet spot and how your pelvis settles into your saddle before you can effectively start trying to ride in your steepest postion possible...


Couple things to watch out for....people sometimes don't have a comfortable saddle and end up moving there seat too far foward for a front end that is relatively high...you get crunched up and the pelvis is too vertical for seat tube angle...The tendancy here is to raise your saddle too high...don't do this...

If you follow the process above you don't need any measuring tools...I can tell you that you will measure very well.....


Now with that being said...If you don't know if you are on the right size bike...don't really know how to make adjustments and/or generally figure things out then you might want to consider a professional fit...

But it really isn't that hard.... The biggest issue that newbies run into is that they have a bike that is too big for them with respect to how low they are gonig to be able to get....(the bike is too long and they end up stretched out....)






BTW - if you want to feel which adjustments effect which muscles you can overexagerate your fit in either direction and your body will tell you right away...

Put your seat back to its furthest fore/aft postion...(make sure saddle isn't too high) and then get pretty low in the front (so bend at the waist (which will close your hip angle off)...and you will feel glutes big time (you won't be able to spin a cadence very well, but you will feel the leverage from pushing behind the bottom bracket).........Put your seat really far foward (all the way) and your will feel you quads burn....



Well, I was mainly trying to figure out the cause of my hamstring tendon pain. Basically I went from a position that I know was too far forward (it was as forward as possible), and it was most likely a little too high and I got pain in my left hamstring tendon. So I moved it lower and further back and my next ride I had some pain the next day again, but I am assuming it was just not all the way better from before... But if you are saying that further back is more hams then I guess that is not the answer for me. I mean I took a video of my new position on my road bike, but its not on a trainer its just me going back and forth in front of the camera a few times...
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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Best position depends on your strength which will dictate flexibility. Your hamstring weakness is leading to your hamstring strain. Lower your seat a bit and move forward over the crank. More power less strain. If you feel you hamstrings still you are likely pulling back and up which is a useless activity to power a bike and causing your problems not your strength or setup.

Technique will always last longer then energy production. Improve biomechanics, improve performance.
http://Www.anthonytoth.ca, triathletetoth@twitter
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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Hamstring problem is probably more of a function of (too high of a saddle)...Which was probabaly the case if you were riding too steep...(this is a common overcompensation)

Moving you seat back will engage posterior chain more (ie..glutes and hamstrings), so if your saddle is still too high it will make the hamstring issue worse...Sounds like it wasn't completely healed though...

The goal isn't to ride saddle back or forward...it is to find optimal for the amount of rotation (drop) you desire and can handle up front...But this is proportionate...

Chances are you have been riding a saddle too high for a while and your body has adapted, so it feels more powerful...but what is really happening is you are unloading and cutting off a significant portion of the arc of the pedal stroke....
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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You can't make that kind of a declaration, a seat that is slack doesn't necessarily mean more posterior chain engagement. A lot of pros cyclists ride slack and have large quad muscles, a lot of triathletes ride steep and have more slender quads. Your glutes become more engaged as you upper leg moves to the posterior side of your body, something accomplished more in steep angles. When you're pedaling, from 12 oclock to 3 oclock your knee has to extend because the pedal moves away from you, the slacker you are, the more quad dependent this movement is.
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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Have a read throu the fit articles, start here:

http://www.slowtwitch.com/...it_system/index.html
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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http://www.arniebakercycling.com/books/b_bike_fit.htm

______________________________________
"Competetive sport begins where healthy sport ends"
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Re: Bike seat positon and muscle recruitment? [HXB] [ In reply to ]
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HXB wrote:
You can't make that kind of a declaration, a seat that is slack doesn't necessarily mean more posterior chain engagement. A lot of pros cyclists ride slack and have large quad muscles, a lot of triathletes ride steep and have more slender quads. Your glutes become more engaged as you upper leg moves to the posterior side of your body, something accomplished more in steep angles. When you're pedaling, from 12 oclock to 3 oclock your knee has to extend because the pedal moves away from you, the slacker you are, the more quad dependent this movement is.


Move your seat really far foward without adjusting the stack and reach and tell me what burns? The only declaration I was making is that there isn't a more foward or slack postion that is going to make you a more powerful/faster rider...There is an optimal position for our relative rotation around the bottom bracket that will engage the appropriate muscles...

1. Obvioudly Cycling utilizes the quads...The size of your quads is much more dependent on genetics and the type of training a person does than there bike postion....

2. The case I was making above was a bit of an oversimplification....However, I can see how you think that the quads become much more dominant from a slack saddle because you are looking a more knee extention...The quads are knee extenders...However this is also an over simplification because the top of you pedal stroke is still effected by hip flexion before you transiton back down to hip extension...12 to 3 is not going to be the peak power phase of your pedal stroke...

3 oclock is right in the range, but again that depends on your relative steepness which will effect the force vectors (directional force)...because peak force is going to get applied when hip extention is a primary mover....

To make the point above of need to use more knee extension from a more slack position is oversimplified with respect to peak pedal forces as well because a lot of riders who ride relatively slack are more than likely heel droppers which allows them to still generate power from all that is involved in hip extension....

again...this is oversimplified, but I am not sure of your level of experience with respect to biomechenics as it relates to the body applying and transefering force....

Could what you were explaining above be true...Yes, I am sure...but there other factors at play....My experience with most new riders who experience fit problems is a saddle postion to steep for a relatively high front and it puts a lot of stress on the quads and knees..............which consequently causes them to raise the saddle too high...
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Re: Bike seat positon and muscle recruitment? [Triathletetoth] [ In reply to ]
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Triathletetoth wrote:
Best position depends on your strength which will dictate flexibility. Your hamstring weakness is leading to your hamstring strain. Lower your seat a bit and move forward over the crank. More power less strain. If you feel you hamstrings still you are likely pulling back and up which is a useless activity to power a bike and causing your problems not your strength or setup.

So you are thinking that its not related to my position at all, I am just being a retard and pulling with my left while my right leg is in its downstroke? I honestly think this might be it, what should I do to get rid of that habbit?
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Re: Bike seat positon and muscle recruitment? [thejunk] [ In reply to ]
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Stop pulling up. Ride on top of your shoes not strapped down. Only put body wt on the pedals at 1-4 o'clock and relax the rest of the time. We can do more doing less muscles work on a bike and relaxing.

Technique will always last longer then energy production. Improve biomechanics, improve performance.
http://Www.anthonytoth.ca, triathletetoth@twitter
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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Big wrote:
There is an optimal position for our relative rotation around the bottom bracket that will engage the appropriate muscles...


x 10.

From what I see I would guesstimate 10% of triathletes riding time trial geometries actually rotate around the bb. The rest jam the saddle up as far as they can, keep posterior tilt, chop off their pedal stroke and have all sorts of back/neck/lower extremity problems. It's not like they are doing it to punish themselves...they just don't know what they don't know. Sadly there are a few fitters in my area who are clueless to pelvic tilt and rotating around the bb. Modus operandi is jam saddle to rear of rails and call it a day and when I listen to people talk about the agony they are in on their new $5K machine I just cringe. 'Oh my fitter says I need to work on my flexibility and then all this will go away'.
Last edited by: tigerpaws: Jan 25, 13 2:24
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Re: Bike seat positon and muscle recruitment? [tigerpaws] [ In reply to ]
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Hi Big, I know this is an old topic but there lots of good infomation here. I have ridden for a good 5 years, and I've had low back pain i trained in a very exeessice postior pevlic tilt and flexing at the low back big time, over the years I hve built up my spinae erectors lots of muscle mass there now, since I've seen this post, about 4 months back I've aimed to get more of a neutral/anterior pelvis from what i've experianced if my glutes are more stimulated in the pedal stroke my spinae erectors relax more and I have less pain.. I found a really comfortable postion that stimulated my glutes big time and my low back relaxed.. only a few days after I picked up a hamstring injury.. thinking it was the bike, it was actually a pull i did off the bike.. so I moved my position back and totally forgot about the measurements.. Since then I cannot find that position again and would like to try get my glutes working lots more, I found that my cadence dropped, but I felt more comfortable and more power.. and centre of gravity was really good corners improved.. My quads were pretty fresh too.. My sprint seemed different as I probably had to shift body further to get to the front, unless its the glutes that are being overworked and they cant contribute as much to the sprint, What do you think off this? Have you experienced with anyone or yourself, where the low back can get overactive/painful if the glutes are not being stimulated? I hope you reply back as I know this topic is old. Cheers

Edit - I should mention my posture is very good off bike, I am classed as a 'high function freak' But when it comes to being on the bike my low back wants to fire and my glutes don't..
Last edited by: SamYO: Aug 20, 14 8:34
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Re: Bike seat positon and muscle recruitment? [SamYO] [ In reply to ]
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Bump
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Re: Bike seat positon and muscle recruitment? [Big] [ In reply to ]
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Big wrote:
HXB wrote:
You can't make that kind of a declaration, a seat that is slack doesn't necessarily mean more posterior chain engagement. A lot of pros cyclists ride slack and have large quad muscles, a lot of triathletes ride steep and have more slender quads. Your glutes become more engaged as you upper leg moves to the posterior side of your body, something accomplished more in steep angles. When you're pedaling, from 12 oclock to 3 oclock your knee has to extend because the pedal moves away from you, the slacker you are, the more quad dependent this movement is.



Move your seat really far foward without adjusting the stack and reach and tell me what burns? The only declaration I was making is that there isn't a more foward or slack postion that is going to make you a more powerful/faster rider...There is an optimal position for our relative rotation around the bottom bracket that will engage the appropriate muscles...

1. Obvioudly Cycling utilizes the quads...The size of your quads is much more dependent on genetics and the type of training a person does than there bike postion....

2. The case I was making above was a bit of an oversimplification....However, I can see how you think that the quads become much more dominant from a slack saddle because you are looking a more knee extention...The quads are knee extenders...However this is also an over simplification because the top of you pedal stroke is still effected by hip flexion before you transiton back down to hip extension...12 to 3 is not going to be the peak power phase of your pedal stroke...

3 oclock is right in the range, but again that depends on your relative steepness which will effect the force vectors (directional force)...because peak force is going to get applied when hip extention is a primary mover....

To make the point above of need to use more knee extension from a more slack position is oversimplified with respect to peak pedal forces as well because a lot of riders who ride relatively slack are more than likely heel droppers which allows them to still generate power from all that is involved in hip extension....

again...this is oversimplified, but I am not sure of your level of experience with respect to biomechenics as it relates to the body applying and transefering force....

Could what you were explaining above be true...Yes, I am sure...but there other factors at play....My experience with most new riders who experience fit problems is a saddle postion to steep for a relatively high front and it puts a lot of stress on the quads and knees..............which consequently causes them to raise the saddle too high...

https://www.youtube.com/watch?v=0BiCpRbDauM
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