Firefighter for four years here, I checked out Athlete Strong Athlete Lean as I have never heard of it. I honestly think it looks like a great program, to be a firefighter you need to be very well rounded...that program will do the trick. Explosiveness, strength, and conditioning are all really important. We have all types of people at the firehouse; the powerlifting but no conditioning guy, the bodybuilders, the crossfitters, and so on so forth. Some of the strongest guys at our house I wouldn't want to follow me in, they get gassed damn near before we even make entry. The crossfitters struggle with some of the heavier job tasks but make the bottles last much longer than most. Athlete Strong Athlete Lean looks like it will give you a great mix of everything. Out of everything I'm saying here....make sure you are well conditioned, you really dont want to be the guy that has to make his crew back out of the fire after a few minutes from being so out of shape.