i thought i mentioned in passing by way of the runner example, but i guessed i need to spell it out a bit clearer.
when i heard the word "athleticism", in my mind, i thought of runner, swimmer, weight lifter, high jumper, basketball player, soccer player, and so on. from my point of view, athletes trained to be one dimension dealing with force. if a push straight from the front of an athlete he/she/it would push straight back. however, if someone would apply a force lateral to the athlete at the same time, his/her/it would have a hard time dealing with it. if you watch some of the soccer plays, you would see a soccer player running full tilt and if another player body check him/her from the side, the running soccer player would often goes tumbling into the grass. IS folks basic training is to be able to deal with forces coming at many directions at the same time - up, down, front, back, left and right - to name a few. so from my point of view, IS training, at the foundation, is multi-dimensional force neutralization. now, if normal athlete learn such training, would make them much better athlete than before. the soccer player would keep on going and score!
(yup! me likes soccer!)