Tosas are fought even if they can barely stand up. Somehow they pull themselves together for enough time to do their thing. Absolutely, must do xrays to see where the hips and elbows are at before breeding. Many dogs can do well on poor hips, but their offspring might not be so lucky. I put my dogs in a 12 mile endurance trial, and run them regularly to make sure they have strong structure and good health. The majority of Tosa breeders think they have xray vision, and can tell if their dog is dysplastic LOL