Well, I thought of yet another aspect of swimming to analyze for my blogs posts!!! Sometimes at practice we use these bungee or stretch cords to work on resistance training. The premise is simple, strap one end around your self, and the around the block at the end of the lanes. The bungee cords act just like a spring in that F = -Kx, the further the displacement the larger the force. As you get closer and closer to the other end of the pool, the force pulling you back becomes larger and larger. This especially sucks when your coach is pulling on the other end, leaving you just enough slack to get really close to the wall but not enough for you to be able to finish!