I think that one of the biggest reasons we always see such huge blocks from behind by LeBron is because of his world-class closing speed. He once again put it on display for us last night as the Heat were in Charlotte to take on the Bobcats.
Watch below in the footage courtesy of Gamedayr. In it, watch as LeBron times a perfect block against Kemba Walker, as Walked appears to think he has an easy open lay-up. The ball ended up in the crowd.