Originally Posted by
thump55
Clipless may not "significantly" increase power output, but it allows you to maintain the same power output for a longer time, which is in all reality, an increase in power.
I've never seen a single scrap of evidence to support this claim.
By using other muscles besides the main "push down" group, you spread the burden around which makes all the muscles involved last longer.
You use the same muscles, whether or not you use any foot retention.
Researchers and experts like Andy Pruitt have used pedal-based power meters for years. No one adds power on the upstroke, not even top pros. All you wind up doing is lifting your leg, without losing contact.
Clipless is not about power, it's about control.