Originally Posted by rod9301
wondering if there is any research that substantiated the need for these stretches vs any other ones.
Unfortunately there is rarely research about very specific topics. The challenge with things like sports performance is that for research to be valid, you really need to look pretty long term, and you need to be able to isolate talent vs training vs skill training. This is true for all sports, and frankly for most training topics at all. There is research on training being done - some of it good some of it not so good, but there are so many factors it's virtually impossible to make meaningful conclusions. I was an engineer before I became a trainer, and so I'm used to the answer always being either 0 or 1, and always being provable. Not so much with the human body!
There is research on stretching as it pertains to performance, and both the quality of the study and the results are mixed. Some of the studies are borderline useless as they do things like testing to see if stretching reduces injuries. They do this by having a group of people either stretch or not and then perform their sport, and then they count the injuries. Since the purpose of stretching is largely acknowledged to be long term movement quality and thus also long term injury reduction, a single episode is meaningless. Not surprisingly, the result was no difference.
There is some favourable research about dynamic warmups, which is what the exercises in the on-snow video are, although I don't think there is any pertaining to skiing.
Definitely no research on the specific band hip activation exercises above. I'm a fan of following what the research says if there is some of quality. But in absence of that, we're stuck with what makes sense based on theory and experience.
What I notice with the mini-band exercises is that people's knees move better in exercises like squats and lunges. I see much less knee collapse. If a person can't stabilize in a controlled environment (a squat at the gym), odds of them being able to stabilize in a dynamic environment (skiing) is very slim.
For the dynamic warm-up part, all I can suggest is that you try it. Do that for a few days on snow, and try not doing it for a few days. Notice anything? Myself, my ski buddies, and those who have reported back to me have all felt the warm-up helped. I've experienced similar results personally and as a coach in ultimate as well - a good warmup does help.
Now on the flip side, a guy like Pavel Tsatsouline (who is awesome - a former Russian special forces instructor and creator of the Strongfirst KB certifications), says that if you need to warm-up for an activity, you're not ready for the activity. I think there's some truth to that, although I think that statement needs perspective. If you're a 25 or 30 year old member of the special forces, then your body should be such a machine that it is ready to perform at all times. But if you're a 45 year old skier with a desk job, then odds are against you that your body is ready for anything at all times without preparation. While the enemy won't wait for the special forces operative, there really is no need to go from lodge to skiing in 3.5 seconds. Unless it's a power day.