Low Inertia vs High Inertia

wiredued said:

I have a trainer with a 6 lbs flywheel which is considered low inertia I've heard that low inertia trains fast twitch muscle fibers better and high inertia trains slow twitch muscle fibers better. If I got the 18 lbs flywheel would I notice a drop in L6 and L7 power and an increase on the aerobic side of the power curve?

It doesn't seem at all possible that you could change your physiological characteristics by riding a different trainer. Maybe I am missing something?

Maybe I am too. 😕

I don't believe I've ever seen trainers classified as either low or high inertia, but flywheel weight is not the only factor in inertial loading. What makes your KK Road Machine a 'low inertia' trainer?

I guess rollers would be about as 'low inertia' as they come, but I couldn't imagine anything about them that would specifically train or develop the fast twitch fibers. That depends on the power level at which you train rather than the inertia of your trainer.

This may not be a true statement maybe the guy is just talking through his hat or maybe he has some studies to back it up I don't know.

jeffdevlin.comindoor.phpOpen ↗

"There have been a few studies on stationary trainers that suggest that the inertia of the trainer affects the muscle fibers and how they are trained. Low inertia trainers require more use of fast-twitch fibers while high inertia trainers more effectively train slow-twitch fibers. A few more popular trainers that would be considered "high inertia" trainers include Velo Equipe's Chaindriver, Velodyne Sport's Ve
lodyne, Racermate's Velotron and most "spin" bikes."

wiredued said:

This may not be a true statement maybe the guy is just talking through his hat or maybe he has some studies to back it up I don't know.

jeffdevlin.comindoor.phpOpen ↗

"There have been a few studies on stationary trainers that suggest that the inertia of the trainer affects the muscle fibers and how they are trained. Low inertia trainers require more use of fast-twitch fibers while high inertia trainers more effectively train slow-twitch fibers. A few more popular trainers that would be considered "high inertia" trainers include Velo Equipe's Chaindriver, Velodyne Sport's Velodyne, Racermate's Velotron and most "spin" bikes."

Did he provide the reference anywhere? I did not see any. I tend to more agree with frenchyge, its not the machine rather the power levels that affect muscle fiber recruitment (and training).

However, spin high-inertia trainers are more specific to cycling biodynamics, I believe this provides a clear benefit to high-inertia trainers. They certainly feel more like riding a real bike.

I'm inclined to go with john979. In my experience, lower inertia trainers tend to recruit greater involvement from the hip flexors. This may be OK for certain physical therapy reasons; I consider it an artificial "limiter". By this I mean that since the hip flexors aren't used as much out on the road as they are on indoor trainers (normal or "high inertia"😉 they may become a limiter to how much power one can put down indoors vs. outdoors.

My 0.02 and not based on anything factual,
dave

wiredued said:

This may not be a true statement maybe the guy is just talking through his hat or maybe he has some studies to back it up I don't know.

Interesting. First I've heard anything about that. Maybe send the person an e-mail asking him for references to the studies he mentions.