I've been doing submission wrestling/BJJ for 8 years. I have no idea when I got them. I had an MRI last year and they showed up. I had an MRI about 10 years before, and they were not present. So I know the injuries occurred during that training period.
I know of at least 5 other high level guys that have the same injury. Some had surgery, some have tried to maintain without surgery. I haven't had surgery, but it's likely I will need it eventually.