Don't want to derail, but anything that "returns energy" has injury potential. Think about it this way - you land and a foam absorbs and disperses. Energy gone, but shoe feels dead. Zoom and Boost - you land and energy is returned back up the leg - in theory- causing a ripple effect as the body comes down and energy goes up. Instability instantly, if you don't have body control.
Just a theory.
I agree. Coming off of meniscus surgery I had lot of trouble with sneakers with zoom airbags. They would feel amazing but after a game or two my knee would be sore and I'd have to stop. I didn't have a problem with retros that included zoom like the Flight Ones. I think its mostly because the zoom airbag was surrounded by foam. I also had no problems playing in lunarlon or any other foam for a long period of time.