You can use this Workout as a Warm-Up, but its no upper back included! The last two exercises are in a bridge, as you can see my upper back is not open there. Focus on this exercises are to strengthen your lower back muscles and your glutes, to get a better active cobra or a better closed bridge.
If you wanna do backbending afterwards please do some exercises for your upper back (like wall stretches) too!
You can even enjoy a nice 15 min workout for your easy stretching days. 🙂