I was watching some American Football, and I noticed that the kicker Blair Walsh wore a white shoe on his right (kicking) foot, and a black shoe on his left. Is there a reason for this? Does it benefit the kicker somehow?
Team trainers and players work within NFL guidelines for player equipment. The colors do not benefit the kicker or team, but must "conform" to NFL equipment guidelines.
"League-approved tri-colored shoes are permitted with black, white, and one team color."
"Punters and placekickers may wear any combination of tri-colored shoes provided that the colors are consistent with those selected by the team and with the policy listed above."
Generally speaking, one shoe is important for gripping the turf, the other for striking the ball. Shoe soles may however, vary in their number, arrangement, shape, material, diameter and length of cleats.