Planking
This is very good for your back. You can lie on your stomach on the floor and engage your back by lifting your arms up. When you plank, you can feel your back getting stretched out and your core getting strong.
Pushups
Pushups are great for your arms and chest, but when you get lower into the contracted position, you’re engaging your back and using your body weight to gain muscle. Hold your position at the bottom for a couple of seconds and then push back up to make your muscles work harder.
Dumbbells
There are a variety of ways you can use dumbbells to your advantage. You can do dumbbell press, hammer rows, dead lifts, opposite toe lifts and many others. Check out this video:
At the Gym
There are a couple of machines you can use at the gym that will make your back muscles stronger. You can take a spinning class where you can use an upper body bike, which makes you push up hard, waking up your back muscles. The rowing machine works your back great because you are using your whole body, especially your arms and back strength.