Question

Short answer

Rising on your tiptoes cannot be done because gravity will exert torque on the body.

Step-by-step solution

Understanding the center of mass

Whenever a person is standing on their tiptoes, the center of mass of their body changes in the forward direction and the chances of falling are more in this case.

Explanation for the position of the person if they try to rise on their tiptoes

When a person is in a position where their feet astride the door with their nose and abdomen touching the edge of the door, the center of mass cannot shift toward the forward direction.

So, gravity will apply some torque on the person, and they will not be able to stand on their tiptoes and return to the floor flat-footed.