"Good Mechanics Is Everything"

"...as sports physicians, we've all been amiss for years worrying about putting people back together and fixing things and new techniques. But we've largely ignored the real problem: prevention of injuries. Everybody now agrees that the time is right to keep these kids from getting hurt so often. That's been my mission for 10 to 12 years, and it's really come to the forefront that last three to four years."
http://www.cleveland.com/dman/index.ssf/2013/02/noted_surgeon_dr_james_andrews.html

"... [your] kid needs at least two months off each year to recover from a specific sport. Preferably, three to four months. Example: youth baseball. For at least two months, preferably three to four months, they don't need to do any kind of overhead throwing, any kind of overhead sport, and let the body recover in order to avoid overuse situations."

"PD: What advice would you give pitchers, in general?

J.A.: 1. Use proper mechanics. The No. 1 problem in any specific sport is improper mechanics."

The good news for all of us is that "using good mechanics" is also the key to generating the most force, whether that be with a baseball, a spear, a barbell, or manipulating one's own body through space for pull-ups.  

The problem is so few of the folks who coach kids have any idea what good mechanics are, or how to teach kids how to move well.

The keys to the CrossFit kingdom are to understand mechanics in every application of human force generation, and understanding how to coach any client who walks through the door how to achieve those mechanics.