Tri vs. Road

"Mike Jacoubowsky" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

This isn't correct. What John claims is that, by paying very careful attention to the details
(and with the aid of wind tunnel testing), you

can

Quoted message said:

be *nearly* as aero sitting further back and a little bit higher, vs. sitting forward and lower.
But Boardmanesque positions still generate

the

Quoted message said:

Quoted message said:

least amount of drag...

So it then comes down to more efficient due to increased power output with the seat further back?

That's the theory, anyway. However, I find that I can generate just as much power with my seat only
2 cm behind the bottom bracket as I can with it 8.5 cm back, consistent with all published and
unpublished physiological data on the subject. I therefore think that people who *know* (vs. think -
a crucial difference, in this context) that their sustainable power is lower when in a really aero
position simply haven't moved their seat forward enough (i.e., thigh-torso angle too acute).

Andy Coggan

"Andy Coggan" <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

"Mike Jacoubowsky" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

This isn't correct. What John claims is that, by paying very careful attention to the details
(and with the aid of wind tunnel testing), you

can

Quoted message said:

Quoted message said:

be *nearly* as aero sitting further back and a little bit higher, vs. sitting forward and
lower. But Boardmanesque positions still generate

the

Quoted message said:

Quoted message said:

least amount of drag...

So it then comes down to more efficient due to increased power output with the seat
further back?

That's the theory, anyway. However, I find that I can generate just as much power with my seat
only 2 cm behind the bottom bracket as I can with it 8.5 cm back, consistent with all published
and unpublished physiological data on the subject. I therefore think that people who *know*
(vs. think - a crucial difference, in this context) that their sustainable power is lower when
in a really aero position simply haven't moved their seat forward enough (i.e., thigh-torso
angle too acute).

You are right, but I've never understood why people even _think_ that sitting further back is better
power or efficiency wise. It's not as though the arrangement of muscles and bones changes or muscle
function is impeded or anything, it simply represents a rotation.

Maybe it's all down to the Guillmard/Lemond testing. I've only ever read wishy washy reports on
that. But apparently they found sitting back to be more comfortable, more "effective" (whatever that
means) more efficicient and more aerodynamic!

Andrew Bradley

"Andrew Bradley" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"Andy Coggan" <[email hidden]> wrote in message

news:<[email hidden]>...

Quoted message said:

Quoted message said:

I find that I can generate just as much power with my seat only 2 cm behind the bottom bracket
as I can with it

8.5

Quoted message said:

Quoted message said:

cm back, consistent with all published and unpublished physiological

data on

Quoted message said:

Quoted message said:

the subject. I therefore think that people who *know* (vs. think - a

crucial

Quoted message said:

Quoted message said:

difference, in this context) that their sustainable power is lower when

in a

Quoted message said:

Quoted message said:

really aero position simply haven't moved their seat forward enough

(i.e.,

Quoted message said:

Quoted message said:

thigh-torso angle too acute).

You are right, but I've never understood why people even _think_ that sitting further back is
better power or efficiency wise. It's not as though the arrangement of muscles and bones changes
or muscle function is impeded or anything, it simply represents a rotation.

Try this: put your bike in a relatively big gear, then power up a moderate hill while staying seated
with 1) your seat (hips) well back, and 2) your seat (hips) well forward. Presumably you'll sense
what I do (and what everyone else does), which is that it is easier to engage the hip extensors
(i.f., gluteus maximus) under condition 1. I realize that gravity should not impose the frame of
reference for us, but it certainly seems to...in any case, I think it is this impaired ability
to generate *peaks* in power that makes people think that sitting back is necessary to time
trial well.

Andy Coggan

Andy Coggan said:

Quoted message said:

Quoted message said:

I find that I can generate just as much power with my seat only 2 cm behind the bottom bracket
as I can with it

8.5

Quoted message said:

Quoted message said:

cm back, consistent with all published and unpublished physiological

data on

Quoted message said:

Quoted message said:

the subject. I therefore think that people who *know* (vs. think - a

crucial

Quoted message said:

Quoted message said:

difference, in this context) that their sustainable power is lower when

in a

Quoted message said:

Quoted message said:

really aero position simply haven't moved their seat forward enough

(i.e.,

Quoted message said:

Quoted message said:

thigh-torso angle too acute).

You are right, but I've never understood why people even _think_ that sitting further back is
better power or efficiency wise. It's not as though the arrangement of muscles and bones changes
or muscle function is impeded or anything, it simply represents a rotation.

Try this: put your bike in a relatively big gear, then power up a moderate hill while staying
seated with 1) your seat (hips) well back, and 2) your seat (hips) well forward. Presumably you'll
sense what I do (and what everyone else does), which is that it is easier to engage the hip
extensors
(e.g., gluteus maximus) under condition 1. I realize that gravity should not impose the frame of
reference for us, but it certainly seems to...in any case, I think it is this impaired
ability to generate *peaks* in power that makes people think that sitting back is necessary
to time trial well.

I do of course sense what you and "everyone else" does in these conditions, but I believe this to be
a misinterpretation of the effect (though it could well be at the root of the belief).

Many also believe that a high saddle gives "more power" and I think the two are connected.

If you sit on the back of the saddle, you are increasing effective saddle height which makes a given
gear feel easier to push (for leverage reasons - one of which I may go into in a separate thread as
I'd like somebody to BS check it, but the easy one is moment arm variation at the knee joint).

If you were to lower the saddle appropriately then sit on the back of it (or gear up appropriately)
I'm not sure you would feel more powerful. I know I never did.

Personally (and for other people I know who have tried it) if I move the saddle forward (as compared
to "the norm"😉 I feel I climb _better_ than sat back since more hip-stabilising reaction force is
available from gravity, what with me not being a spinner on the hills...

And of course the sprinters sit forward.

Andrew Bradley

Andrew Bradley said:

Personally (and for other people I know who have tried it) if I move the saddle forward (as
compared to "the norm"😉 I feel I climb _better_ than sat back since more hip-stabilising reaction
force is available from gravity, what with me not being a spinner on the hills...

I think the moving back may be utilizing the muscles slightly differently, to the extent that tired
muscles rest and rested muscles work.

When my legs hurt, pushing up a hill, and I slide back a few inches and pedal more forward than
down, I feel like I'm using entirely different muscles, especially the ones in the bottom of my
thighs. I get new power that way, and it helps, when I remember to do it.

Quoted message said:

And of course the sprinters sit forward.

I'm certainly no sprinter. 😉

Quoted message said:

Andrew Bradley

--
Rick Onanian

Rick Onanian <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Andrew Bradley said:

Personally (and for other people I know who have tried it) if I move the saddle forward (as
compared to "the norm"😉 I feel I climb _better_ than sat back since more hip-stabilising
reaction force is available from gravity, what with me not being a spinner on the hills...

I think the moving back may be utilizing the muscles slightly differently, to the extent that
tired muscles rest and rested muscles work.

When my legs hurt, pushing up a hill, and I slide back a few inches and pedal more forward than
down, I feel like I'm using entirely different muscles, especially the ones in the bottom of my
thighs. I get new power that way, and it helps, when I remember to do it.

Yes, you are definately using the muscles in a different way (though they're the same ones). The
range of muscle-contraction will be shifted along the available range (and widened slightly in all
probability). Also the leverage changes will likely be different at knee and hip, modifying relative
contraction speeds and forces of the various muscle groups.

You might even find yourself ankling off the higher saddle. Apart from getting out of the saddle, i
used to find that was the best way to give the muscles a "break" on the hills. Now I do it all the
time, I never get a break...

Andrew Bradley

Andrew Bradley said:

You might even find yourself ankling off the higher saddle.

What's "ankling off"?

Sounds dirty...or maybe like a fishing term. <G>

Quoted message said:

Andrew Bradley

--
Rick Onanian