Why does Corey channel his energy into training at Bestway, the Brazilian-Jiu-Jitsu gym, in the novel, The War For Gloria?

Through the novel, Corey seeks an outlet to channel his aspirations. Training at Bestway, the Brazilian-Jiu-Jitsu gym is one such pursuit. He begins to train here soon after Tom and he have a heart-to-heart, and Corey is remorseful for being a hoodlum. The energy he previously wasted hanging out with Dave, he begins to channel at Bestway. Corey takes his training seriously, using the only money he does not spend on essentials, for training equipment and food.