Support Your Back when Riding Horses

you can modify the exercise with your belly on a fitness ball or chair. Using the fitness ball from time to time will also challenge your balance.
If improving your alignment and balance is high on your list try using the exercise ball or placing squishy surfaces such as cushions pool noodles or balance cushions under your knees and hands.
However you do the exercise its important to keep your torso square to the floor. Do not allow your hips or shoulders to turn or rotate or your lower back to sag in. If you cannot lift your arm very high its a sign that you need to also be doing stretches to open up your shoulders more.
Stretch Flex and Extend Your Spine
To help keep your spine healthy and mobile its important for your vertebrae to be stretched gently forward flexion and backward extension.
Round your back from a standing position or on all fours.
Next spend a few minutes with your back bent backwards.
Laying back over a fitness ball footstool couch arm or other prop will allow you do completely relax into the stretch.