So for every action there is an equal and opposite reaction. This is the most simple form of physics and at the basis of human form and movement. The thing that amazes me is how many "coaches" forget this important notion or may be they just don't understand the concept. There are so many "concepts" or "gimmicks" out there.
When looking at technique or a technical model remember the human body is not a machine, the technical model should be a base for what an athlete looks like, however athletes come in many different shapes and forms.
You can look at the three fastest men on the planet. They all look different, Usain Bolt is tall and thin, Yohan Blake is short and stalky, and Justin Gatlin is a hybrid of both the fore mentioned. To make generalizations that would be beneficial for all three could be done but each one still has to have their own distinct style and method.
The reason I bring up this topic is I've listened to coaches, read blogs, and hear coaches spewing information that is not based on any of Newton's principles. Maybe it's a lack of knowledge or maybe too much belief in their own knowledge. I'm fortunate because I am able to surround myself with some of the most brilliant minds in the world. If you haven't read Ralph Mann's book on the sprints and hurdles then you need to go out, buy it, read it, then read it again.
If you don't understand it then just live by these easy principles:
1. The fastest people create the greatest forces in the shortest amount of time
2. Strength to weight ratio is critical, so athletes need to be "fit" and strong
3. If you are looking at a technical sprint or jump issue that happens distally from the body you must first look at whats happening proximally (the feet only can do what is created at the hip)
4. The body cannot get into ideal positions if there is a lack of postural stability and postural integrity
5. It takes hours to become an expert, so quantity needs to be balanced with quality
6. Always learn, seek new knowledge, The first book every coach should read is: Neurophysiological Basis of Movement
7. Finally ask questions, we are afraid of sometimes seeming ignorant, ignorance is not a bad thing, it is simply a lack of knowledge
Head Coach and founder of Maximum Velocity Athletics.