Which is the best position and instruction for a scoliosis client to strengthen lateral benders of right side trunk?

Position: Sidelying with a pillow under the head, knees bent and stacked, the affected arm extended overhead, and the unaffected arm across the body.

Instruction: Inhale, then exhale and lift the hips and knees off the floor, keeping the legs and arm extended. Hold for 5 seconds, then slowly return to the starting position. Repeat for 10 repetitions.