Interesting topic...as I think I also do the "toe clenching" thing on the bike, as well as during my runs. I have been dealing with some major foot pain lately, and I think the toe-clenching might be adding to or even causing some of the problems. On nearly every ride, I get some degree of toe-numbing in my right foot only. Sometimes, it comes on rather quickly (within the first 20 miles)...and other times, it doesn't strike until well into the ride (past 50 miles). I have been fitted to my bike (a Cervelo S2 road bike), I wear Northwave cycling shoes which have a very wide toe box, I'm using a large platform pedal (Time RXS), my cleats are positioned correctly, and I always wear Smartwool cycling socks when I ride. So, from my perspective...I seem to be doing everything "right"...yet still suffer with this toe pain/numbness to some extent on every ride. It's very frustrating, and can often turn what should be a great and enjoyable ride...into sheer misery. Same goes for running...I start out fine, but by the first mile...the pain and numbness kick in with a vengeance. I've been fitted for my running shoes in addition to having my running gait analyzed, but the problem persists. I should note, that on BOTH of my feet...my 4th toes underlap and curve inward to my 3rd toes. I suspect that this may be contributing to some of my pain, but I'm not 100% certain. I have also thought that maybe it could be a neuroma, but I don't display all of the classic symptoms...so again, I'm not sure. Anybody have any insight or advice they'd be willing to share? Thanks!