There are many exercises out there that can strengthen your back. Here’s a few of them:

• Superman Exercise: Lie face down on the floor and lift your arms and legs simultaneously. Doing this helps to engage your lower back muscles. 
• Lat Pulldowns: Lat pulldowns target your latissimus dorsi muscles which play an important role in your overall back strength. 
• Pull-Ups: Pull-ups engage multiple muscles in your back and arms, helping to build your upper body strength and back strength.