Golf's a game of precision motor control, while insanely long drives might be evidence of cheating, it's hard to imagine a way to make yourself more accurate besides skill, at least without it being obvious on live television.

Biking obviously involves a lot of different things but it's much easier to see how doping is going to help.

Football has so many facets that it's kind of surprising there aren't more cheating scandals, but at the same time it's harder to isolate any one thing and say that's what's giving a team an edge.

Michael Phelps rose to prominence after most of the big doping scandals by which point anti-doping measures were well established. Besides doping, it's tough to cheat at swimming.

With chess, it's trivial to have a computer on your person capable of beating any human alive, it's just communicating with said computer that is a challenge. Given that chess masters are supposed to be extremely good at strategy and making clever moves people won't see coming, I'm sure there have been some ridiculous cheating attempts.