Conventional Wisdom vs. Science
"Conventional Wisdom has been defined as an opinion that has been repeated so often, by so many people, for so long, that it has subsequently become accepted as fact."
- Tom House
Unfortunately, a lot of what is taught in pitching is based on false conventional wisdom, not biomechanical studies or science. The reason for this is the human eye is not capable of processing movement fast enough to see the critical movements in a pitchers delivery. Therefore a discrepancy has been developed between what coaches believe they are seeing versus what is actually happening.
With advancement in video and 3D technology, along with many years of research by organizations like the NPA (National Pitching Association) and RDRBI (Rod Dedeaux Research & Baseball Institute), many false conventional wisdoms have be tested and disproved.
Here are just a few of the most common false conventional wisdoms (there are many more) that have been disproven by biomechanical studies. I realize that I'm probably offending some that currently teach these conventional wisdoms, but admittedly I did as well until I learned about the newest technology and studies. The key is to stay open minded, focus on the best interest of the players, and know that there is always something new to learn.
"Stay Back, Don't rush".....False!
Elite pitchers begin forward movement before reaching the top of their knee lift, creating an energy angle, getting to foot strike quickly.
The "center pole" of the kinematic sequence is timing to foot strike. When slowed, it has a compounding negative effect on performance and health.
"Pull Glove to Body"......False!
In real time many elite pitchers give the perception that they are pulling their glove to their body, but in reality, they are working their bodies to the glove, maximizing their release point distance.
"Throw over the top, create downward angle".....False!
When an effort is made to change a pitchers arm position to create a more downward angle, you are actually creating more biomechanical failures, such as: reduction in release point distance, decreased late ball movement, reduced actual and perceived velocity, and poor upper body/head position. Downward "movement" should be taught, not downward "angle". If you disagree with that, you would have to tell Randy Johnson he was doing it wrong all those years.
If you're interested in the data collection behind these studies and learning more
about the many other false conventional wisdoms in pitching, they can be found in
Tom House's book "Building A Million Dollar Arm", A Science Based Guide
to Pitching Health and Performance.