Like you said there are questions of efficiency, but hardly any questions of effectiveness. By clipping in and being able to muscle around the full rotation might burn more calories, but it does allow you to push out more watts. Try climbing a 10%+ incline clipped in vs flats. You might be more tired at the top of the hill clipped in, but with flats you'll likely spin out and be forced to hike your bike. Regarding this study, I don't think form in cycling can be trained on the typical trainer. You'd need a rocker plate and something raises/lowers your fork to perform any of the movement that outdoor riding requires.
>Try climbing a 10%+ incline clipped in vs flats. You might be more tired at the top of the hill clipped in, but with flats you'll likely spin out and be forced to hike your bike.
Doesn't "spinning out" mean your power output is bottlenecked because you can't move your legs fast enough? It only happens when your gear is too low. I don't see how that's possible while climbing, regardless of what pedals you use. I ride with flats, and there's a 10% incline hill not far from where I live. I've climbed it several times (at about walking pace) and never had any problem.
