the argument is convincing if you accept that corrolation = causation. the easy thing to say is "well what else explains the change in fumbles" - dunno, but i'm not convinced it's having a little less air in there. i would love to hear from a RB how helpful it is having a ball at 11.5 psi instead of 12.5. i suspect it gives you a slightly better grip... but i maintain my (completely unfounded) belief that it doesn't account for that sharp a drop in fumbles. now maybe other things they started doing to the ball (scuffing, rubbing, etc) might explain it, but i just don't see how air pressure explains it.