We had our Yorkie in it for a while. I didn't think we'd ever get her to do the 4 jumps, and then the swimmer's turn, and another 4 jumps; but, she surprised us, and was doing it consistently. There was no way she could compete with the speed of the other dogs; so, I pulled her. She was good for 2 solid runs, and then she'd lose interest, and scavenge for biscuits on the floor. The other thing she would do was break from her lane, and go for the other dog. We let her do trials; but, she was never in an actual race.