Tom Dempsey
For 43 years, kicker Tom Dempsey’s 63-yard field goal had been the longest in history until Matt Prater made a 64 yarder. This in and of itself isn’t problematic, but some teams questioned whether Dempsey gained an unfair advantage because of his special footgear. Since he was born without toes on his right foot, he wore a shoe specially-shaped for playing. It was basically a half-shoe that came with a hardened, flattened surface to allow him to kick with, but there was never any conclusive evidence supporting the claim that it gave him a definite advantage. Nevertheless, the league introduced a rule which states that kickers wearing prosthetics are required to have the prosthesis shaped like a normal foot, but Dempsey was grandfathered in.
Martin Brodeur
In the NHL, goalies stay mainly in front of the goal, though that wasn’t the case with Martin Brodeur. He had exceptional stickhandling skills and the league theorized that allowing him to play the puck from behind the net gave him an unfair advantage. He was great at neutralizing the dump and chase, which is a strategy involving sending the puck to the corners and going after it in order to set up plays. When other teams tried it against him, they would end up with the play suddenly going the other way, since he could go after the puck and have the skills to counterattack with pinpoint accuracy. The “Martin Brodeur Rule,” as it is unofficially known, states that a goalie cannot handle the puck if they are behind the net, except if they are standing in a trapezoid that is behind the net.