I've had a serious lower back injury about 3 years ago and thought to share my experience so far..
Up till the injury happened, I used to practice martial arts focusing on Taekwondo (which involves mainly kicking/ using your legs to attack). Since I was about 12 I was in love with the sport.. always practicing and later competing.
One time I was training at a gym and they had a really heavy punching bag. That's where the injury comes in.. I used to practice this move where you push the bag away from you, and as it's coming back and gaining momentum I would jump and do a flying back kick. The bag at this gym was so heavy and I probably tried to kick it so hard, that my back was never the same after that kick...
To make a long story short, my doctor told me I'd never heal or fully recover. She said all you can do is pain relief therapy. She said as you get older, your back doesn't just get better. That's not how things work she said. I was depressed, I quit martial arts, and tried to find another sport where I can work around my injury.. that's when I started bodybuilding.
As I was learning basic lifting principles and applying them in the gym, whenever I told anyone about my injury their 1st reaction was to tell me "STAY AWAY FROM DEADLIFTS AND SQUATS!!" I followed their advice at first. I was making good muscle gains in both my upper and lower body, but my back was always weak, the pain would always come and go, I was constantly trying to relieve the pain, etc.. up until recently, when the pain has simply vanished!! Here's how it happened:
First I was trying the lower back machines at the gym and also tried doing hyperextensions. Both were very bad ideas as the pain would always get worse after doing these even with almost no weight. I thought maybe doing lower back exercises wasn't the greatest idea.. But later for some reason I thought of trying the dreaded deadlifts. I started with very light weight (just the bar). I was surprised I didn't have much discomfort from that. I was happy. I tried it again and again each workout. For 5 months now I've been slowly working my way up with weight. Now I can do a few sets of 135lb 15 - 20 reps easily with no pain/ discomfort. I started doing this with almost every workout I do now!
Now my lower back is getting stronger. I no longer need physiotherapy. I can do front squats with heavy weights and get a good leg workout too. This really has been a miracle exercise for me. From now on I'll never go without deadlifts! The best exercise known to man!!