Bad Back Chin Ups?

[hardcorejab]

I am trying to find a way to keep my back mass. I normally train back twice a week with heavy rows, pulldowns and deadlifts. I have always had a bad back since childhood. Heavy training actually improved my posture and allowed me to compete in some local powerlifting competitions. Two years ago I picked up a heavy printer at work and have been in pain ever since. I am trying to find a way to continue working out my back without being crippled the next morning or permanently. My back issues are as follows. I have scoliosis, slight arthritis and few lower discs that are almost gone and pinch a nerve. Had scoliosis since I was very young. The disc touching the nerve happened when I was 13 lifting something really heavy overhead. The other dissc just got worse over time. I have seen some of the top orthopedic doctors and they say take pain meds and wait a few years. They dont recommend injections or any back surgery. They also wanted me to loose weight so I dropped from 320 to 270 and tryin to get to 240( bodyfat now at 23%). Trying to swim as advised, but I suck as a swimmer. Doctors said no physical job, moving any furniture, or weight training. Funny thing doing laundry, dishes and sitting in certain chairs kill me way more than trainin. Sometimes the pain is so bad I cant sleep and my wife has to help me out of bed. So what about chin ups and any other advise.