This is one of the most impressive things I've witnessed in training. This is tremendously hard to do. This is Olympic athlete Emily Azevedo brakemen for the US. She trains under John Carlock, who was just recently in Outside magazine. (My favorite magazine) John runs the Colorado Springs training facility. If you doubt how hard this is, try it out and feel your hamstrings about blow off the bone, most people and high level athletes can't even lower themselves to the floor under control!