The Physics of The American Ninja Warrior Warped Wall

I was watching American Ninja Warrior the other night and watched as contestant after contestant made it through the entire course and then failed to get up the warped wall. The warped wall is 14.5 ft tall (4.4m) and almost completely vertical. Contestants must run up it, grab the top, and pull themselves over. The hardest part for most contestants is getting high enough up the wall to be able to grab the top. This made me think about why this obstacle, that looks much simpler in nature than others, is the reason so many contestants fail. Additionally, what do the contestants who make it up the wall do differently than those who fail. Obviously, taller people have an advantage as they need don’t need to get as much height from the wall. However, numerous shorter people have completed the wall and many taller people have failed. The contestants starts with completely horizontal velocity and momentum as they run across the short runway that needs to be converted into vertical momentum once they reach the wall. Momentum is mass x velocity so the smaller contestants will need to be faster in order to achieve the same momentum. In order to change the direction of the momentum, a force is required. The forces on the contestant include the normal force of the wall on the person, the force of gravity, and the force of friction of the feet against the wall. One thing I noticed is that all of the people who made it ran up the wall in about two steps and then jumped slightly off the wall. This allows the contestant to continue accelerating upwards while the contestants who continue their jump in the direction they were already moving collide with the wall before they reach the top. They lose energy from colliding with the wall whereas the contestants who jump slightly outwards, in an ideal situation, would have conservation of energy and momentum until they reach the top ledge. The contestant must exert a force on the wall large enough to get them to the top. This force comes largely from their thighs. The force exerted on the wall must be enough for the person to overcome the force of gravity, which is mass x acceleration due to gravity. 

A 5 foot tall woman completing the wall: https://youtu.be/XfZFuw7a13E?t=172