Yes boxing is a sport! And you don't see boxers in the MMA (mixed martial arts) cage, which is the closest venue for real world fight situations we have. My point? PP stresses more real world situations, and at the end of the day the question for your PP dog is, will he protect you in a real world situation...although that anwer may be the same in some situations for both sport dogs and PP dogs, in others, in my opinion it will be very different! And that is the difference.