While there are several variables in which can lead to injury today we look at the Stress/Strain Curve and how it can either help our bodies adapt or cause them injury. The amazing part of the human body is our ability to adapt to stresses placed on it but as you will see too much stress or the speed of the stress can lead to injury. The Science behind how the body functions.
Is there something you'd like answered just let me know. If I can't answer it I have access to a lot of Medical Professionals who can. The human body is amazingly complex so always verify the 'expert' that is giving you advice.