I searched for about 20 minutes and couldn't find an answer. I heard(from boxerworld.com) that you should be very careful about exercising/over exercising your boxer until about 15 months because of their growth plates. Major is 9 months old, 24" at the withers, and about 50 lbs. I run him at the dog park 3-4 times per week, and he loves it. Once he's tired we go home. I also take him on walks. I don't want to stunt his growth or ruin his growth or anything because he exercises too much, but he has soooo much energy. Any thoughts?