I recently rescued a Sheltie/ Aussie/ JRT? mix from an in-state animal control facility. She has since been to the vet and tested positive for Lyme and heartworms. After much consideration, I've decided to go with the slow kill heartworm method, due in part to her activity level. She came to us with a slight limp which seems to be improving after 90 days of doxy in case it was Lyme related arthritis. As she has now been spayed and completed the antibiotics, I'm interested in possibly doing a sport with her. Would agility (not competition level, just for fun) at one of the local clubs be a viable option, or can it be much more stressful on the joints than I'm thinking... any other suggestions? She loves being outside and is very food motivated and has the trainability of an aussie. Any ideas that might be okay given her past medical history?