Slowly in Oct of last year I was squating over 350lbs, I know it's not a lot, don't laugh. Now its june and I have to psych myself up to try and break 150. Most of it is mental I know I can lift it, but I'm scared of hurting myself again, and get really nervous every time I lift.
One my therapists is a personal trainer and competes in a local bodybuilding circuit, so he understands my goals and needs. That has probably helped the most, the first therapists I saw told me if I squatted again I may lose my ability to walk. Seriously, this is the advice I got.
By the way I've been back to lifting for about 1 month now so this is really slow progress. Hopefully it is slow enough. I tried to do more bodyweight training for about a month but there is no substitue for lifting heavy things. I have had to changed my warmup though and now takes about 20 min. This is spent getting the blood flowing, dynamic stretching, bodyweight excersices, and lifts with just the bar.
I still have not tried any box jumps yet, my therapist is trying to talk me into trying them, but I'm hesitent, again probably mostly mental. Also, there is still discomfort, but limited pain. This occurs usually when my posture, lifting and not, is less than perfect at all times. Supermans have probably helped the most with this.
Sorry for the long response.