Saddle Height and Power Output

tonyzackery

I don't profess to be an expert, but it appears to me what is being communicated here is an increase in seat angle (higher numerically) results in higher power for a given effort; aka increased efficiency. Lowering the saddle height effectively increases your seat angle, with the reverse decreasing it.

I too have experimented tremedously with this concept and have discovered I am most efficient with my knee approx. 1/2 forward of the pedal spindle at the horizontal pedal position. Due to the fact I have large feet (size 48 or size 14) getting my knee over the spindle of the pedal (let alone forward of it) to set up fore/aft saddle position is difficult if not impossible with any seatpost that has a setback. Ergo, I use zero setback or Profile Design's forward seatposts. I experience higher power with lower heart rates (everthing else being equal) with this forward saddle position, irrespective of saddle height (within reason, of course).

FYI, I use time trial/triathlon frames for road races and crits due to the fact their (tt/triathlon ~ 75-78 degree, and road ~ 72-74 degree) seat angles are greater than traditional road frames.

Experiment with it. Keep within the UCI rules - tip of saddle must be at least 5cm behind bottom bracket in a vertical plane. Be wary of any suspect handling traits with this forward position.

This works for me, it may or may not work for you...

swampy1970

Yeah, but this testing was done on a hill on a road bike. No "ass higher than head" aerobar positions here.....

sogood

But you'll still get more power if you sat a bit more forward on your saddle. Typical TT position (aerobars don't help with power production but reduce power loss and possibly even reduce power production by restricting chest expansion).

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Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac

Billsworld

Do those guys even sit? They sure do spin though

sogood

Clearly it's a case of Virtual Saddle™.

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Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac

Steve_B

I always thought the power loss was probably due to a tight torso-to-femur angle.

swampy1970

I've always wondered about that and it's something that I keep meaning to test on a steep hill with a fairly constant gradient. My road bike has a fairly steep seat angle and I have an old Look Ergostem so I can basically put the bars whereever.... Maybe one day I'll pop the bars up and see what happens.

Training on my old time trial bike I didn't notice any drop in speed or cadence (in a given gear) when changing from the regular bars to the aerobars. Then again, we did spend close to two months getting the position dialed in on a fully adjustable ergometer beforehand, so maybe mine really isn't a valid comparison.

sogood

Any body posture change that restrict your respiratory muscles will limit your chest movement and ventilation. Diaphragmatic compression from tight torso-femur angle is just one part of it.

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Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac

jbvcoaching

No argument there, I think SteveB was hoping you'd show evidence that lung capacity is a limiter in aerobic power production in healthy (i.e. - no lung disease) humans.

sogood

No direct experimental data apart from first principle. Maybe I should be more evidence base and search Medline.

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Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac

Steve_B

I guess if someone rode with a metered gas mask at FTP in both road and (compressed torso-to-femur angle) TT positions and compared the VE and VO2 between the two positions, we would know, right?

I doubt that I'm the first person to propose that.