First, almost everyone has some disc structure that's amiss. That doesn't mean that's causing you any pain or ever will, and it can mean it will cause you pain. It's very hard to tell, because if you talk to orthopedists who look at MRIs, they will tell you that all humans especially after age 35 have problems there. Again, most people never notice it. What they're more likely to notice is muscle strain. Strengthening your core theoretically also helps your back, as it takes some of the strain of activity off the back. But as to which exercises to do, and how to do them correctly, for that you should seek professional help. Getting advice on the internet doesn't show you very well how to do these exercises, and you can't tell the internet, hey, that one hurts. You can tell that to a live person. Physical therapists do this, as does anyone who specializes in sports movement medicine. Some will be good at it, some will be terrible at it. A question: are you in pain now, and does exercise cause you pain?