^^ Yes, thanks Sylvia. I recall reading that article last year. It's interesting to take a look at it again. Many of the U.S. men mention the physical demands and also the mental challenges in training the quad, but none of them really speak specifically regarding the necessary pre-conditioning and all around physical monitoring required. (Probably they all are engaging in such warm-up, cool down and massage therapy strategies as part of their overall training in general, but it seems as if it's even more important to focus on in training quads).
In reading the article again, I took particular note of the fact that Max Aaron and Alexander Johnson both spoke about the importance for them of perfecting their triple jump technique first: "Aaron's first step was to refine the technique of his triple Salchow so that he got into a rotating position in the air faster..." And per Johnson: "I started working on the basic technique of my triples, and when that felt solid enough to try a quad, we went for it."
Ross and others mention the "toll on your body," and Doug Razzano cautions: "... don't overdo it and listen to your body because these are the jumps where the injuries happen." So, therefore, IMO a more structured and well-thought out training and conditioning approach should be carefully designed and implemented (taking into account physical variations and different needs and tendencies among individual athletes). As it is now, it seems to be a kind of Wild Wild West atmosphere with everyone trying stuff out and toughing it out to see what works best for them and when the showdown with the quad occurs event after event and season after season, it's just the luck of the draw as to who remains standing in the end. And even then, without a better overall strategy and physical conditioning program with orthopedic check-ups, multiple injuries and surgeries might loom either before or after retirement.
In regard to injuries stemming from overuse of the quad, probably a lot depends upon individual athletes' physical makeup and training strategies. For example, Ilia Kulik has not seemed to have suffered many (or any?) quad-related injuries, but then he didn't compete the quad over a long extended period of time. He won Olympic gold in 1998 at the age of 20 and promptly retired.