When a hiker gets trapped under a one-and-a-half ton piece of sandstone, he is shockingly able to throw off the slab. Because we normally use only one-third of our muscle fibers at a time, the potential for more is available in emergencies. See street jumpers utilize the strength of their bodies as well. Though not many scientific explanations are given, this is a great resource to pique interest and stimulate analysis. The clip ends abruptly and picks up in part three.