For a long time, we have believed that repetitive lifting causes back problems. It seems to make sense that repeated loading on the spine can cause degeneration of the discs and spinal joints. But studies have not been able to confirm this idea.
In fact, a recent study from Finland suggests that routine (daily) physical loading of the spine may have a training effect. The old sayings, Motion is lotion and Move it or lose it may be true once again.
As it turns out age, body weight, and genetics may be the key factors in back problems from degenerative disc disease. Older age and higher body weight may be more important in disc degeneration than physical activity at work or during our leisure time.
If it turns out that routine or repetitive loading actually benefits the spine, you may be ahead of the game. This type of activity may actually delay the effects of aging on the discs.