When moving down in space all the joints should be free to move.
The habitual reaction is to over tighten by pushing down which causees excess tension in the feet as well as the legs (and back).
Be aware of the soles of the feet and keep undoing/preventing any gripping/tightening working with the head going forwards with the lower legs to counterbalance the back going back – achieving a deep stretch.
When the directions build down the legs and they antagonistically work against the directions up the spine – there is a spring in your core.
The habit energy is for the muscles of the legs to pull the lower spine down through “doing”. Through conscious awareness you maintain the upward direction through the spine – starting at your sitting bones working upwards.
At the same time the legs are directed forward and away from the back. Note the upper leg bone is not vertical – it falls inwards from the hip joint before resting on the 2 supporting lower leg bones.
This orientation coupled with the antagonistic directions creates a supported sprung core.
See the resource centre for a skeleton app that is very good to navigate through.