Originally Posted by
Hermes1
It is true racers cannot afford to have their foot fly off the pedal when attempting to accelerate and clipless pedals prevent that so agreed. However their is also an efficiency component to wearing clipless, if the rider is pedaling correctly, since clipless pedals enable the rider to pull through and up in the pedal cycle.
They measured it on pro racers and found it to be a myth -pro racers unweight the foot, but don't pull up.
I believe they measured this on a trainer which replicates being on the flat, so there is some debate over whether people might get a little additional power pulling up when sprinting, or going uphill. But the idea that racers were gaining extra power or efficiency on the flat by pulling up on the pedal is a complete myth.