Holding a weight plate with both hands directly in front of your chest, start seated on a yoga mat with knees bent and heels firmly planted. Lean back slightly so that your abdominals are engaged and you are balancing on your sit bones. This is your starting position.
While keeping your lower body as still as possible, twist your torso to the right and gently touch the medicine ball on the mat next to your right hip. Untwist your torso to return to the starting position.
While keeping your lower body as still as possible, twist your torso to the left and gently touch the weight plate on the mat next to your left hip.
Untwist your torso to return to the starting position. Continue alternating between right and left for 20 reps total (10 on each side).