I read Tom House’s book “Fastball Fitness” and in it they produce a study in which participiants- youth, high school, and college throw from their knees and velocity radar readings are recorded. House’s evaluation of the participants found that elite pitchers throw with 40 to 60 degrees of hip/shoulder separation. The average velocity increase from the knee drill to pitchers mound was 15MPH. From that, House also concluded that about 80% of velocity was from hip/shoulder separation and 20% from stride, direction off the mound, and arm speed.
My question is, how can they assume arm speed to be apart of the 20% making up stride? Although by having his participants throwing on their knees, House eliminated the directional/stride part of the equation but he didn’t do anything to eliminate arm speed.
One way of making it a more effective study is to have the participants sit cross legged - shoulders continuously square to the target. That way you can see how fast each individual’s throwing arm moves without other influences such as hip/shoulder separation and stride/direction off a mound.
There is no denying House as a knowledgeable pitching pioneer, but I’m giving you some reasoning as to why arm speed isn’t one of three factors making up 20% of pitching velocity.
What do you guys think?