Back bending means also opening the chest. The shoulders pull back. This is a movement we don't do often in daily life. Back bending asanas like urdhva dhanurasana, but also kapotasana aim at opening the upper chest. I got some additional asanas. I put the elbows next to the head on blocks. The palms lie on the back. I am on my knees. Important is that the thighs are vertical ( 90° ankle to the floor). The chest pulls to the floor. Gravity helps.
"20 breaths", M said last time. I feel that this exercise is good for me.
I'll go to a Mysore class this morning. It's cold outside. I refuse to dress a winter coat!