What is a one-sentence summary of the following article?
Over-exercising your dog when he is young can lead to bone and joint issues that may lead to the development of hip dysplasia. Gentle, low impact exercises can be beneficial for puppies, but avoid letting your pup run, leap, or jump until he is physically mature. High impact sports like jumping and leaping can be hard on your puppy's developing joints, so avoid doing these activities with your puppy until he is fully developed. Keep your dog active to help him stay physically fit with moderate exercise like running, walking, and swimming. Dogs with large, strong leg muscle mass may be less likely to develop hip dysplasia than dogs with a smaller muscle mass. Activities that might apply too much force on your dog's joints, such as jumping for a Frisbee or leaping for a ball, can lead to development of hip issues. Consistent walking, running, and swimming can help your dog build muscle strength without putting too much stress on his body.

Summary:
Do not allow your dog to run or leap when he is a puppy. Take your dog on walks or runs when he is an adult. Avoid doing a lot of jumping activities with your dog.