Ryan Hall is a jiu-jitsu black belt, ADCC bronze medalist and proprietor of 50/50 BJJ in Arlington, Virginia. He's also the winner of a recent four-man tournament at the UFC Fan Expo in Toronto, Canada that was part of the UFC 129 extravaganza.
In this video above, Hall talks about his match with UFC welterweight Diego Sanchez. Hall eventually won on points, besting Sanchez 8-2 despite a 30lbs advantage for the Greg Jackson-fighter. Notably, though, Hall says he felt one of Sanchez's knees "pop" from injury during one of his patented 50/50 heel hook attempts.
Why bring this up?
Sanchez has a fight against UFC Hall of Famer Matt Hughes pending. There's no date set, so it's entirely conceivable Sanchez has recovery time if, in fact, he was injured from the heel hook. That's still disconcerting Sanchez would refuse to tap in a grappling tournament when he's got a hugely important fight on the horizon.
As for Hall, don't be mad at him. He's using legal techniques and releasing the dangerous heel hook submission the moment the fighter taps. In fact, I've included video of Hall's previous match at the Expo against Jorge Britto. You'll not only see Hall's mastery of the heel hook 50/50 variation, but Hall talks to critics in the comments section of the video about his techniques and why they're perfectly appropriate: