@anon103 That's a really good question and deserves more upvotes. I made it sound way more definitive than I should have. I edited the post.
Here's the injury history as I remember it:
With both protocols I experienced the very early warning signs of an injury but nothing more. I had a slight twinge in my shoulder when doing an arc row during a 1x work out. I started taking my shoulders through the full range of motion every day during my light activity and warming up more thoroughly for hard workouts. I had no issues from then on. In fact, I was surprised at how hard I was able to go without feeling any pain whatsoever. This was especially true with the one arm chin up progression. Again, I’m a sample size of one, but I felt like I was limited only by my capacity for discomfort rather than by my tendons. Personality plays a role here because I am a very risk averse person… I’ve never even tried skin the cat because I’m too scared. That’s why I did overhead press instead of HSPU. Less cautious people might need to be careful about doing progressions they can’t handle.
On three different occasions, I tried very slowly adding in an exercise to my 7x workout that caused a slight twinge after about a week. Those exercises were arc rows (elbow issue), ring push-ups (elbow issue), and tuck L pull ups (shoulder twinge). Each time, I took a week off of burnout sessions, did some slow wrist extensions and rice bucket exercises, and had no issues. I still do those exercises in burnout sessions but it seems like some things just shouldn’t be done every day. Personally, it feels easier to prevent injury with 1x because my body stops me from going so hard that I injure it. With 7x, I have to be careful. YMMV