can you please better describe this action using the muscle…

can you please better describe this action using the muscles:
9. Lie on the stomach. Have the knees wide enough for it to be possible to place the two soles of the feet one to the other, on the floor. Then, lower the legs and, like this, lean them on the sides. The toes move outward and the lower legs are in the air and the heels are in the middle. The heels are toward the middle and the toes point outward.
Like this, extend the legs wide, like a frog. Now, place the left hand on the floor. Place the left temple on the back of the hand. Lift the right hand and look at it. Allow the legs to adapt so it will be possible to lift the hand comfortably and to roll the head. Allow the right leg to bend even more. The right arm is almost long, almost completely extended forward, forward and up, long.