Originally Posted by charles vail

This is a hot button in my book. It has long been my contention that the only thing foot retention does is encourage confidence, to spin like a madman, at a proper cadence, for maximum performance, in all weather, wet or dry. Having said that, I can site a reference from a book by a former trainer of U.S. Team cyclists who has coached racers to more than 50 U.S. National Championships who is himself a medical doctor, a consultant to US Cycling and the USCF plus, he is a Cat 1 USCF racer and 5 time national champion. Dr. Arnie Baker states on pg. 118 of his book, on the subject of pedal stroke, he says," pulling up forces were once thought to be significant......however, re-examination of the data and subtraction of the inertial forces of the legs has shown that these forces are not as strong as was formerly believed. Elite cyclists are more effective because of their greater downward forces, rather than because they unweight their pedals or pull up more than recreational cyclists."

I believe the only benefit to pulling up with retention is, it rests your muscles slightly and at the same time allows your feet to stay on the pedals. Of course the same thing can be done without attachment by just slightly lifting the upward traveling leg but thats not something you do in a race.
For recreational cyclists, clip in retention is hardly neccessary and good foot retention can be accomplished by other methods without the drawbacks of clip ins or simply by using wider platform pedals with traction and regular shoes with a softer sole. This combo actually for me has proven to be supremely comfortable as I use sandals and my toes are free to wiggle around, keeping my feet from going numb. The wide pedal surface area lowers psi and you get no hot spots or pressure points. This is simular to walking on flat ground as opposed to walking on the edge of a narrow rail. It also dispences with the need for overly stiff shoes since the pedal is wide enough to spread the load. Of course this approach doesn't sell shoes and pedals so its not popular and for those with $$$ invested in clip ins they won't want to admit to having purchased or promoted a solution to a non existant problem.

To each his own ultimately.