In a Cat Cow you're in a quarter pad stance, move your shoulders blades up and down, and band and extend your spine. In a hollow body position to pull your chin to chest. Make sure to keep shoulder blades to deep pressed all the time and Don't let them fall into elevated position. Imagine, to push your shoulders as far away from your ears as possible. In a hollowbody position you have to tilt your pelvis backward, by pulling your belly button to spine. In addition to that you should rotate your elbow pits forward to stabilize your shoulder joints. This outward rotation should be kept for the complete exercise. When you switch to the arched back position you need to retrack your shoulder blades to get all out this movement. Don't overstretch a neck, but keep it in a neutral position. Pay attention to elbows and keep them extended all the time. A Lev 2 you lift knees off a ground, which makes the exercise is hard to stabilize and coordinate. This exercise mobilize to complete spine and prepare shoulders for upcoming stress and release stress from a neck.