The lead/stride leg in pitching is rarely understood correctly and is often analyzed from a baseball-specific viewpoint. Unfortunately, the best throwers in the world are not baseball pitchers, so to truly understand how the lower half properly works, we need to get out of our comfort zones to disrupt the standard model of analyzing what’s already being done. Breaking things down from an anatomical and kinesiological viewpoint, we start with Frans Bosch talking about the “footstrike from above” concept from his newly-translated book on human movement and strength training:
The idea is that the footstrike should not “slide into” contact with the ground but rather should be directed nearly with the line of expected Ground Reaction Forces (GRFs) we are hoping to create. Baseball-specific research corroborates this finding; in Stride Leg Ground Reaction Forces Predict Throwing Velocity in Adult Recreational Baseball Pitchers (McNally, Borstad, Onate, Chaudhari; JSCR Oct 2015) the following data was presented:
Stride leg ground reaction forces during the arm-cocking and arm-acceleration phases were strongly correlated with ball velocity (r2 = 0.45-0.61), whereas drive leg ground reaction forces showed no significant correlations. Stepwise linear regression analysis found that peak stride leg ground reaction force during the arm-cocking phase was the best predictor of ball velocity (r2 = 0.61) among drive and stride leg ground reaction forces.
In an analysis of this research paper, Graeme Lehman discussed it further, stating:
The most important direction however wasn’t the vertical but rather in the anterior/posterior direction. Here is a direct quote from the study.
“Force imparted by the stride leg against the direction of the throw appears to contribute strongly to achieve maximum throwing velocity”
The fact that the stride leg is applying force AGAINST the direction of the throw means that this force is being applied in a posterior direction. The back leg gets our momentum going towards the plate in an anterior direction but the we must “slam on the brakes” and stop our momentum by applying force backwards with the front leg. This catapults our body and ultimately the baseball towards home plate.
While back leg “drive” did NOT significantly correlate with increased ball velocity, lead leg posterior force did. This can best be viewed by the following clip of Shohei Otani from the Nippon Professional Baseball (NPB) league in Japan, their version of MLB. Otani has thrown 101 MPH in a game and regularly sits mid-high 90’s! Watch how the lead leg not only compresses vertically downwards, but claws backwards in a direction opposite of the throw before it rotates over due to residual momentum of the trunk and hips following through:
Want more proof of the “clawback” mechanism? How do the world’s best runners actually make contact with the ground when producing maximum force?
Now the question is: How do you train this mechanism not only mechanically, but using training modalities in the weight room and track to ensure it transfers properly to the pitching mound and develops strength/power over the range of motion expressed in the pitching delivery? That’s a question for another day, but this betatest of a new ImMotus Training method at Driveline Baseball might give you some ideas to get kickstarted!
For more information on our flagship book on developing elite fastball velocity, be sure to check out Hacking the Kinetic Chain!
Want to learn more about what we know about efficient pitching mechanics? Check out the wide array of blog articles we have relating to mechanics here.