Gravity is acting on our bodies all the time. As we eat, look at our phones, work in front of computer, the list can go on forever, unless you are consciously thinking about your posture, the tendency to allow the shoulders to drop forward is normal. Growing up as a dancer, posture was something that I was aware of all the time, however now as I practice and teach lots my shoulders get stronger, but also tighter if I do not give them some love. For athletes, artists, humans, here is a mindful movement exercise for the shoulders and chest that I feel anyone can benefit from.
Start on your belly. Extend your right arm out directly out to the side from your shoulder. If you want more sensation, bend your arm to 90 degrees. Perhaps try both to see what your body is craving. Place your left hand beside your left shoulder. I like tenting my fingers, making my hands look like a spider to keep the hand alive and active. Push into the left hand and roll towards the right. It really does not matter what your lower body looks like, the intention should be stretching in the chest (pectoralis major muscle) and the front of the shoulder (anterior deltoid muscle). Rest your head onto the mat. There is no need strain or stimulate any other muscles. Use gravity in your favour. Let the posture do the work. All you need to do is be there and breathe. I like to inhale to acknowledge the sensation, and then to exhale the "stuff" we may be holding in there. Hold for 5 breaths or as long as you feel guided to do.
If you want even more sensation, lift your left arm off the mat and towards the sky. This allows the body to open up even more. Simply let the body roll to the right as you stretch into the right shoulder and chest. Soften with every exhale and then repeat on the other side.
Below is a video of the movement I do to use gravity to open up my chest and shoulders in my practice and in my classes. I invite you to press play and come play! Namaste.