A few weeks after Plax was released from prison he approached the Sports Science crew and asked to be put to the test. He showed up alone and ready to go. According to host John Brenkus, Plax's jumping and core abilities actually increased over the two years he was away from the game. This, in large part to Burress's focus on working out his legs and core muscles while incarcerated; muscle groups largely ignored while he was active.
Its a fascinating video to watch, you can see the whole thing HERE.