For some people the concept of rolling the balls of your feet is a phenomenon mainly because "ball" is just a term given to the firm front part of your foot, it's not actually a ball. But there is space to manoeuvre the joints inside the foot.
so if you find this hard..
Try rolling your eye balls at the same time. It is a similar sensation and stimulates a relaxation within the third eye in between the forehead where all our thoughts block off the creative energy of the body.
Rolling the balls of the feet feels like nuzzling your feet into the sand.
Your feet can feel the floor-aaah it feels so good!
The bones then, literally reach out to the floor growing from the root, inside the foot so we can become strong from the ground!