In all honestly I would have his back end checked, his gait appears off and I would want to know while he is young if there is something wrong that way I would know how to properly manage it. Better safe than sorry in the long run just to be sure. As for the standard being outdate- no, just no! The standard was written by those with knowledge into the breed. There are actually 3-4 (depending on how you feel about some of the clubs with their own standard) for the breed. The US AKC standard is the only one without height/weight limitations and we are seeing some huge dogs coming out because of the "bigger is better" thought process and it is damaging out breed. They are meant to be one of the most agile of mastiff breeds and as you continue to breed dogs that are too large for standard you start to loose the functionality of what they were original bred for. In Canada our standard has the weight/height restrictions and while you can get larger dogs from correct ones, those looking to ensure the prosperity of the breed don't go seeking to breed them. Breeding 135lb female to 170lb male, I hope they were fabulous examples of the breed with something the breed could just not do without and not just because they were huge we have enough incorrect dogs being bred for profit that rescues are taking a serious hit.