According to fitness coach Belle Badell, “the idea of the chest pop is to squeeze the back muscles and then squeezing the upper abs. …Press the back muscles in and downwards. Press and release. If you ever wonder how Shakira does it, this is the trick.”
I notice Belle tightening and compressing her shoulders and neck as she does this exercise. If people imitate that, they’re likely to feel lousy and have less free movement.
If you’ve got distorting tension patterns that cause bad posture, I doubt you’re going to improve by doing this or any exercise. You’re just going to ingrain the habit of adding more compression to your back, shoulders and neck. That’s going to diminish your breathing and your emotional and physical freedom.
The idea of exercises to improve your posture holds that you can just add layers of corrective procedures to undo the damage of interfering tension patterns. The Alexander Technique instead focuses on letting go of those interfering tension patterns so that you can move more easily. You learn to undo rather than to do.
Shakira has beautiful use of herself and I doubt it is because of the chest pops outlined above.