Today in class we covered more laws of motion. As it turns out, the action of walking/jumping/running (Really, pick one) aren't only because you push down and forward. The floor is actually PUSHING RIGHT BACK. "Equal and opposite reaction", one can almost hear Mr.Meredith mumble. But in stricter terms, every force is met by and equal and opposite force, which is Newtons Third law. When one pushes off the floor, they find themselves back on the floor soon after (at least, one would hope). This relates back to newtons First Law of Motion. An object at rest wants to stay at rest; and object in motion wants to stay in motion. If gravity wasn't at work, pushing off the floor would cause you to keep moving upward until you burned up in the atmosphere or bumped your head on the ceiling (of course there are other forces, friction, etc, however i'll only discuss gravity here). We are actively fighting a war with gravity ALL THE TIME. Our movements are all met by it, all the time. The only escape is space.
Anyways, next time Mr. Tytler makes a backhanded comment about how fast i run a 5K (i admit, the 29 minute race is a bit embarrassing) i'll simply explain my legs are trying to deal with the way the earth pushes them when i apply force, and my body is engaged in the ongoing conflict with gravity.