Question: A person wants to jump in the air. To do so, he has to crouch a distance C. He then has a push-off phase, where the he accelerates upwards by a distance C. At the end of push-off, he then achieves takeoff (airborne). The end of his takeoff distance is H, and H is the difference between maximum jump height and end of crouch distance. My professor says the Cons of E. equation is FC = mgH + WC, with this reasoning: "The total energy you need to take off at the moment of the take-off = F (reaction force) X C (distance). The total energy you spend during the push-off till the take off = potential energy to reach the jumping distance, H (mgH) + kinetic energy to overcome the gravity of the person (WC). Therefore, FC = mgH + WC" I don't quite understand his reasoning for this. Is there something more intuitive anyone can share?