How can i strengthen my back?

Core exercises: Other than spine/back exercises, strengthening your abdominal muscles would be a great way to improve your core strength.

Yoga exercises: One great exercise is to lie flat on your back looking up. Now raise both feet off the floor 2 inches and hold for as long as you can. Then raise your feet 2 more inches and hold again as long as possible. Continue until you are on your shoulders and feet straight up.

Build a Strong Core!: To get a strong back you need to develop your core, especially your abdominal muscles. The best way to build a strong core is to exercise. Exercises that build your core muscles work your entire body. Walking on the treadmill, plyometrics, as well as weight traing are all important. Hope this helps get you started!