My thinking was that it would keep the dogs ticking over. This would be along with there walks and free running . I got a young bull cross bitch gifted when I got her she was very under weigh , and had very little muscle. I have a lot of weigh on her and the muscle is coming ,but very slow just thought it might help ,I'll get there with her. She is a young bitch .Ah ok,I took on a right state of a bull x at 7 months and the best thing I did for him was hydrotherapy 8 sessions of 1/2 hr swims he was a different dog and no stress to the body at all.Mills do have a place within a good excercise