@dshesgreen I have some personal experience with what @yds is saying. What I would have done differently is to start even more slowly on my own, and then get a personal trainer or PT for several weeks before I got to full LIFTMOR movement ranges at full LIFTMOR 80-85% of 1RM. The subtilties in deadlifts are intense.

With no Onero near me, and Personal Trainers very expensive I started various exercises patterned after LIFTMOR type about a year ago on my own. I will credit myself some for working up slowly and my spine T-score is only -0.9. I watched hours of videos about form especially for the deadlift. By 8 months in I was doing back squats with 80lbs and slightly-shallow deadlifts with 100lbs.

When I started to go deeper on the 100 lb deadlift, bending over more, I did a somewhat minor strain in my back that may have been a minor costovertebral sprain. There was no pain at the time, and I finished my gym session that day. Only later was I sore. LESSON: go really slowly with every change in what you are doing and back off at even a whiff of something not being perfect, even if not painful.

The strain drastically reduced my back exercises so I went to my doctor and got a referral for Physical Therapy with a reasonable co-pay to me to heal faster. Every PT session I bugged the therapist to also help me with form on deadlifts and that helped some. But my 2 therapists were more about fixing issues and not as great about advising proper form in deadlift etc. LESSON: pick your PT carefully for exercise form if you use one.

At the end of physical therapy I resumed my hunt for a Physical Trainer searching further afield, and being willing to pay more. I finally found a lower-cost gym that offered 5 sessions for $300. And I could do those 5 sessions scheduled individually. My usual gym makes you set up a weekly schedule for about $100/session and that was not flexible enough.

The trainer was open to the LIFTMOR type protocol and helped me in key points. Most importantly is that she was able to augment how I was bracing my back for deadlifting and supervise me in that until it became rote. The rest of my form was already good she said! Still, I added in more back bracing technique based on videos that reinforced what she was teaching me. The trainer also had me work more with Sumo (wide stance) deadlifts than regular DL.

I have worked my way back to 80 lb back squats and 90 lb full-depth deadlifts. I no longer see the trainer as continuous physical trainer sessions are not in my budget. But if I feel even a hint of something odd, I back off so my training sessions are sometimes only 75 lb squats and 85 lb DL or I just stop free weight lifting for that day and use the gym machines for back extensions + leg press as substitutes.

As much as I love LIFTMOR researcher Prof. Belinda Beck I wish she had tested exercises less tricky than a deadlift.

ASIDE: Technique notes that affected me: Using videos on my own I got pretty good lifting form in most areas according to my trainer. My trainer got me to brace my back more by tightening my arms more as if to pull in both elbows towards my sides firmly as I lifted. And she was able to spot it if I was not doing that enough. Videos helped by adding arm rotation force that. The videos said to pull in your arms as if you are bending the barbell firmly around your legs. When starting on my own I had mostly been bracing based on how my back felt, not what my arms were doing, and not pulling my arms strongly enough.