Obviously, the best way to train for Andrade La Sombra is to keep training. Off-season, shmoff-season; the Colorado Raptors were so tantalizingly close to winning the cup last season and it absolutely came back to haunt La Sombra over the course of the offseason. Even if he wanted to rest at the end of that epic series, he wouldn't be able to. The feeling of that championship and the feeling of coming so close to winning is enough to push La Sombra's training regimen to the max. Weights can be heard slamming against the ground in the Raptors' gym hour after hour, night after night. 
That being said, this likely doesn't fall into a typical offseason for La Sombra; he makes it a point to go back home to Mexico, visiting his father's lucha libre wrestling promotion sporadically. To him, watching what his father and the rest of his family do is something that calms him, and reminds him who and what he's fighting for. That balance is going to be important in the coming years as La Sombra continues his hockey career.