I have another anecdote about this product to share...

A couple of years ago, I got golfer's elbow from doing high volume chin-ups (supinated pull-ups). I'm at an age where this kind of thing is common (I've heard of it referred to as "middle age pull-up syndrome").

I tried to ignore it and work through it, but it got worse, and I eventually went to therapy where they recommended the Flex bar. It took more than a few weeks, but eventually it completely resolved the pain. For me at least, it did the job, and it's a lot cheaper than a single visit to the therapist (even if you end up buying multiple "levels" of it).

Nowadays I do my pull-ups on gymnast rings, so these creaky old elbow joints can move freely rather than being stressed by a fixed hand position.

Same story here. MAPS from frequent pull-ups. TheraBand has kept it at bay. Also switched to gymnastics rings. I also modified my programming to alternate between pullups and seal rows for 6 week training blocks, so I'm also doing half the volume of pullups as I was previously when the pain was very bad. But the elbow pain is practically gone now.

Had Golfer's Elbow and acupuncture did not work - physical therapy with these flexbars worked.

Conversely, my wife's debilitating ankle injury was going nowhere with physical therapy and after a single trip to a local acupuncturist she could walk pain free.

Second this. I believe the real benefit comes from being able to exercise the extensors instead of the flexors, which helps with remedying an imbalance in tendon strength that leads to tendonitis.