Okay, I'm going to throw out the "Stupid Question" warning as a preface -
Why would we need to regress crawling in someone over the age of 5?
@B.Hetzler, Do you mean, "Why would anyone over the age of 5 not be able to crawl and need a regression?" Or do you mean, "Why would anyone over the age of 5 need to crawl at all?"
If the former, a lot of people have difficulty crawling because of wrist and knee issues, but can do dead bugs. Even though I guess dead bugs fall into the crawling category within OS, I think of them as a separate drill that I do for different reasons -- but then, I CAN crawl and so don't need a regression.
Brandon, I've seen a number of your questions about OS on this thread, and here's my general response as a user of OS:
I think I have pretty good base of knowledge and experience of OS: I've attended a two day OS workshop, read the first OS book, and have been practicing a lot of the movements for a couple of years. I'm a user of OS because I've eperienced and observed benefits from it, and it is fun, it feels good while I am doing it, and I feel good generally when I do it regularly.
I think that Tim and Geoff sometimes oversell and overemphasize the theory behind it and the idea of emulating and recapitulating the development of movement skills in children. I don't necessarily buy it, and largely ignore it. To me, it's completely beside the point of why I use OS.
However, Tim and Geoff also emphasize their empirical experience, and present the system as representing a spirit of play, exploration and experimentation. This is how I choose to approach it. Not as therapy. Not through a lens of dysfunction and correction. Not as mobility or flexibility training. Not as warm up for other activities. I approach it as play -- something to do for its own sake because it is fun and feels good to do. I approach it as exploration of and experimentation with movement. I don't look at the categories and principles (changing levels, moving the head, contralateral movements, limbs crossing the centerline, etc) as restrictions or instructions, but as inspiration to explore. If you look at Tim's videos on the OS YouTube channel, he exudes this vibe of play and exploration. He's constantly coming up with different variations, with only the directive to "give this a try."
In many ways, I look at it as just an extension of other physical training that I do, but generally less structured and goal oriented (although there are some "performance" variations that can be loaded and progressed as more structured training), and mostly with little recovery demand.
My take on OS may be a somewhat individual interpretation, but when I read some of your comments and questions about it, my reaction is that the premise of the comment or question doesn't reflect my understanding or experience of OS.