Q: Recently, at a yoga workshop, we were trying to understand how the psoas is released in Vrikshasana/tree pose. I would be grateful if you could explain this to me?
A: Standing tree pose does not “release” the psoas per say but it does take a released neutral psoas to be in the asana. The psoas as core muscle reflects skeletal alignment of the spine and pelvic keystone. If weight does not run through the bones there will be psoas tension and possibly tight hip sockets.
I recommend tree pose first on the floor. If one can articulate the hip socket and free the leg to move differentiated from the pelvis on the floor it is more likely that one can do so while standing. If it is impossible than begin slowly and with the bent leg begin at the ankle, moving the foot up the leg, keeping pelvis level and hip socket articulated.
The focus is to sense your core and pelvis as a whole and to not push past the point where the leg moves the pelvis off center. Weight in tree pose is not on the standing leg but through the plumb lines/center line of the human spine.