Yes, my pants are saggin’, but if you can look past that (lol) this is a really good circuit for rear shoulders/upper back. The emphasis is on posture.
When performing the kick backs your palms should be facing backwards throughout and you should be lifting your entire chest off of the bench while squeezing your shoulder blades in towards your spine. Elbows should be slightly bent, but stiff and not contributing to the movement in any way.
Go straight into lying reverse flyes. Turning your thumbs out as you raise will cause your shoulder to externally rotate. This will force the inferior angle (bottom corner) of the scapulae down – great for stabilisation. 👍🏾
The last move is what I like to call a prone shrug. Focus on squeezing the shoulder blades together while lifting your chest off of the bench. You should feel it in rhomboids.