Let's say the top four men traded some tennis shoes for a pair of running shoes... They all line up one by one on the starting line of the track...Nadal brings out some starting blocks, Federer is finishing his last touches on his hair using his secret mousse...Murray makes sure Lendl is watching in the stands...and Djokovic is simulating how he's going to rip his shirt off when he becomes victorious. The question is...who comes out on top? I would say Djokovic because he kinda has a runners physique, but you never know! So what do you say? And what times would you think they get?