Anyone who has ever pulled a hamstring knows how painful it can be. Former Louisville defensive lineman B.J. Dubose, competing at the NFL Combine Sunday morning, did just that, pulling up lame near the end of his 40-yard-dash run. Dubose eventually lost his balance and fell to the ground as well. It’s tough to watch.B.J. Dubose. That’s no good. https://t.co/ZRBQeo3N0k— Chris Burke (@ChrisBurke_SI) February 22, 2015We’re actually surprised this doesn’t happen more, given the fact that these athletes are giving it their all for four to five seconds. Hopefully he makes a fully recovery.