Djetzel,
I think you need to just take a step back here and look at what people are telling you. It's not that a traumatic injury caused the limp, but over time, repeated jumping/running/whatever have you, can and will have a negative impact on a young puppy's growing structure.
I have been there. I jumped my adolescent border collie too much and too high as a puppy and he ended up with a long lasting shoulder injury and retired from agility early. I wish someone would have warned me about the serious implications of what I was having him do.
The people that are warning you have experience just like I do. It may not be firsthand but they have it. They've been in dogs long enough to see fantastic dogs end careers early because of rushing training.
With my dogs, I am taking the safe route and always have. I've had them evaluated by orthopedic vets for weaknesses in their structure. Zinga had radiographic proof that her growth plates were closed before starting ANY jumping or contact work.
I pay close attention to the flooring and footing before doing any sport with my dogs and absolutely would never, ever throw a disc on concrete floor or even ask for any jumping behavior there. Too slippery and there's no give.
You will always find people who say that it's ok to jump young dogs, or ok to play on whatever surface. You as a handler have to weigh the risks and benefits. I know for me, that one training session is absolutely not worth the risk of ending my dog's career.
So yes, that one session of playing disc didn't CAUSE your dog's injury. However, it certainly didn't help it and adding all of the things you are doing with him at this young age together, it builds up and can eventually cause a chronic injury that presents similarly.
For what it's worth, my vet said it would be ok to do vaults with Zinga when she was 8 months old because her growth plates were "most likely closed".
ETA: that above was an example of bad advice. Her growth plates didn't actually close until 12 months.
I hope I can word what I'm thinking as well as I'm thinking it...
I think I understand, for the most part, what people are trying to tell me. The fashion they are doing it in is what is bothering me the most, since I feel that there is at least somewhat of a misunderstanding. Passive aggressive comments, comments from people I've never talked to before, etc. are not going to help anything.
I bought Recon from a breeder that has been showing in agility, flyball, and herding, for a long time. I have taken all of her advice and contractual limits and followed them to a T. I have been training with numerous successful agility trainers over the years and many veteran showers, all of whom I've gotten advice from regarding how much to do and what not to do, and when. I've gotten advice from my general vet AND a rehab specialist now, as well. I cannot believe that everyone I know that sees us train and knows what we are actually doing is ok with it while everyone online is not. There has to be a miscommunication somewhere. That said, we are taking a session off of training for a variety of reasons regardless, for Recon to heal and rest and build some muscle.
Was the frisbee thing (not on concrete, and with a textured surface, just for the record) pushing it? Probably. And that's why I only did it once and wasn't aiming to make him jump in the first place. I realized that and just, didn't do it again. Not even outside, because he won't chase a disc outside.
And I certainly understand Vets having crappy opinions, which is why I'm not sure why everyone is expecting me to take one vet's biased opinion here... And I say biased because she blatantly dislikes me, frowns upon everything I've ever done, and has publicly mocked or encouraged the mocking and ridicule of me for years. There is no way I am going to trust people that I only know through the internet when I have no reason to trust them because of stuff like this, or passive aggressive comments made about things that they were not there to observe. I do appreciate comments like yours and take them into consideration, which is why I am typing out such a long response.
I'm sure many people would still think that 4" jumps for a puppy once a week or every other week for 5-10 minutes accumulative is too much, but this goes back to me weighing the pros and cons of what I have read, what people are telling me on the internet, and what people are telling me in real life. Weave comments were obviously taken out of context, there is no way I would encourage a puppy to do that sort of impact, which is the same reason we are not doing anything on a contact except for finding 2o2o with a plank and getting used to a teeter moving at low heights.
We take a lot of time in between classes for rest, we warm up well and cool down well, and don't push it. We don't practice much on our own between classes because I am not trying to rush anything. We do a lot of jump sequences at low heights and tunnels/chutes. We do a lot of muscle memory stuff for crosses and sends on the flat. That is all? I thank you for the concern, genuinely.