Quote Originally Posted by beccaB View Post
OK, I hope I won't appear stupid, but what is "degree of float"?
Float means you can move your heel side-to-side (well, more pivoting around the pedal) without coming unclipped. If your pedal doesn't have float, your foot (and, by extension, knee) is locked in place.

Most pedals that have float do not have "free float" and will encourage your foot to go back to the center position. Speedplay pedals have free float, so your foot can move freely and (hopefully) not torque your knee.