Title says it all I tend to keep my legs straight while hitting my two handed backhand any tips or drills to help me solve this?
Early shoulder turn is the key.
As you turn your shoulder away from the ball, you should naturally coil down, bending your knees during your backswing.
During your forward swing uncoil up. Push up off your legs as you uncoil back towards the ball.
Start practicing it to just feel the rythmn of the upper body rotation coodinated with the bending and unbending of the knees.
Practice the rythmic motion with backhands off the wall to engrain muscle memory.
Practice the rythmic motion with a partner who can sustain long backhand to backhand rallies.