Bo Jackson was a freak of nature: at 61 and weighing 16 stone, Jackson was nonetheless one of the most blistering men on the planet, running a (still record) 4.12 second 40-yard dash at the NFL Scouting Combine. A hip injury cut his NFL career tragically short at just four years, but he continued to play professional baseball, and is the only athlete to be named an All-Star in two major American sports. Last year ESPNs Sport Science named Bo the greatest athlete of all time.
