Depends very much on the reason for the wear and tear. The back is a set of synovial joints which means the cartilage between them is fed via a synovial membrane, a system I am going ot over-simplify and someone may slam me for as I explain.
The membrane is like a sponge that is fed into via the blood and squeezed by movement to release some of the nutrients into the cartilage between your discs. This next isn't totally true, but it's close enough to be sensible to treat as if it is. Each movement squeezes the same amount out regardless of pressure behind it, so arching backwards and forwards with no weight will release as much nutrient to the cartilage as one with all the weight you can hold. As I said this is not totally true but the difference is not enough to cover for the next part. The damage to the cartilage is greater the more weight you move with none are without impact but the less weight you are carrying the less damage you cause.
If the damage is because the cartilage is too worn to protect the discs but it is at a level where it could be regenerated by keeping mobile and allowing the nutrients to build it back up, you could add in some weight training when this is recovered enough but will always have to accompany this with low intensity movements to undo the damage done by the overloading weight training, or high impact work. If you go to far you will have to drop such activities again until your cartilage repairs again. This is best case scenario, do not assume it without consulting your doctor to be sure. If you take guidance of someone on the web who has never met you without checking with your doctor if it's safe you are an idiot, and trust me when I tell you stupidity can be very painful.
If the synovial membrane itself is damaged or the cartilage is too damaged to self repair over time you will need to contact a physio to find out what is possible and what isn't and take details from your doctor with you. That is something no-one who can count above their IQ would advise you on without personal contact. Backs are too risky to guide you on without a lot more info. If anyone does treat them with distrust.
If you know what I am directing you to checking out here is not the issue please let us know what you have been told and that will help us help you.
