Another way to do this with less effort is to place a stick under your back and do sit ups as you move the stick from point to point to learn to relax with the ground you are on and to use it to your survival.
lie on your back and tense up your body to the max and hold it for a few heart beats. Relax and repeat this a few times till you feel more relaxed on the ground. Now raise both arms in the air so the shoulders are in the air as well and slowly do a few leg raises overhead. Defend your spine by using your sides and movement to move and check how you can be aware to more of the movement in your back.