You are currently sitting on a chair. Put something soft under your heels. During the exercise make sure that your knees are hip-wide apart and point outwards.
Now imagine three points under the heel that form an inverted triangle. One point is at the back of the heel, the second is on the front inside of the foot and the third is on the front outside. Try to press the points into the ground at the same time.
No part of the heel may lift off the ground or give way during the exercise. The toes also remain on the floor. Do the exercise with one foot first and then switch to the other. Continue with the next exercise for the foot
