The key to preventing back injuries is strengthening the muscles of the back.  A professional athlete would not think about playing their respective sport without training to do so.  Why?  The answer is obvious:  their performance will suffer and injury is likely.  Why then should it be any different for those who do hard/heavy work?  It shouldn’t be.  Any employee working in a physically demanding job should take time to prepare their bodies for their job, just as an athlete would for a sport.  The following link depicts several exercises that can be used to strengthen the back:  Bulging & Herniated Discs