Here are 2 dudes that did a trial, they produced more watts going up hill in flats, sprints were a big difference though. These were people used to being clipped in, and not using flats.
Where's the studies to the contrary? Nothing I've seen has been more than marginal at best.
https://gearmashers.com/clipless-pedals-vs-flat-pedals-faste...
Here are 2 dudes that did a trial, they produced more watts going up hill in flats, sprints were a big difference though. These were people used to being clipped in, and not using flats.
Where's the studies to the contrary? Nothing I've seen has been more than marginal at best.