emceemanners wrote:
Good example of correct physics but wrong conclusion. Reminds me of the sports scientist podcaster that claims running on flat road has no mechanical power going on and means zero work.
"Strength" riders, use low cadence, choose longer cranks and use broad muscle groups at more angles of the stroke cycle (especially glutes and calves at the 12 o'clock). Their feet move SLOWER - because the cadence is lower and ride style smoother. These guys normally have the saddle further back and have their torso higher. many triathletes also gravitate to strength riding when going uphill by shuffling backwards in the saddle.
"Spinner" riders treat the chainring as a flywheel and twitch their thighs up and down with a smaller range of hip and ankle motion. They could benefit from short cranks. These guys are typically further forward over the BB and have less glute and calf activation.
As a low, aero position that doesn't tire out your posterior chain is beneficial for overall long-course performance, shorter cranks (--> spinning) might improve ironman/70.3 performance in most people, in the short term. But only in the same way as if you suddenly only did all your run training on a track with super shoes.
Good example of phenotyping that doesn't stand up to scrutiny. (Sorry, I had to start it the same way).
It's perfectly possible that a "strength" and "spinner" riders have the exact same leg speed. 2pi*(crank length)*rpm=leg speed. 100rpm on a 160mm crankset=100.5m/min. 92rpm on a 175mm crankset=101.1m/min.
FWIW I don't disagree with the saddle position in relation to cadence, that's pretty well established.
But there's no reason to think that using shorter cranks is a fleeting gain that will only apply in the short term. The aero benefits don't degrade with time. Having 'less glute and calf activation' is a mushy term. If you're going to race in a hip-forward, short crank, high rpm style then it's beneficial to train in that style. I don't buy the argument is that people should train on long cranks as a "strength" cyclist even if they plan to race a a "spinner". Train the way you plan to race, and race the way that gets you the most efficient power output.