Is lead knee extension something to work on? I've focused more on the back leg and the hips (Hershiser drill, etc.), but what about the front leg? I've focused on there being no give in the knee. However, is it enough that the knee doesn't give (can remain bent as long as it's stable) or should it actually extend back/straighten before or just after release?
See this hard throwing 14u pitcher, who is on our team, who almost hyperextends his front knee back:
And Verlander, who does the same:
Here is a description of a drill that I found. Does this make sense or does lead knee extension depend on the pitcher/natural result of upstream movements?
Velocity Variable: Push and Lead leg Stability
The strength and stability of pitchers lower body has been proven to be very important for throwing velocity. In 1998, Bruce MacWillams conducted a study that examined ground reaction forces during the pitching motion. The study’s results indicated that leg drive is a significant factor in pitcher’s throwing velocity. The push motion in the delivery is not the only important action of the lower body. The lead leg that blocks forward movement is also an essential element in a pitcher’s throwing velocity. In a 2001 study, Matsuo found that high velocity throwers were able to plant and extend the lead knee to provide stability to the pitching motion. In addition, the Lexington Clinic was provided an outline evaluating kinetic movements. They included a .89 correlation between throwing velocity and lower body strength. The following drill promotes strength and extension of the lower body:
Lead Knee Extension Drill
Objective: To promote forward momentum and the transfer of energy directly toward home plate from the pitching rubber by forcefully extending the lead leg.
Procedure: The pitcher will stand with their feet shoulder’s width apart. Their arms will be crossed at chest level. The pitcher will pivot the throwing foot and kick the lead leg up, just like a regular pitching delivery. With their arms crossed, the pitcher will bring the lead leg down and plant. When planting, the pitcher will have transferred all their weight from the backside to the lead leg. This will be indicted by the back foot sliding forward approximately 3-4 inches. After the plant, the back leg will stop moving. At this point, the pitcher should be in a lunge type position with their weight forward. In the next step, the pitcher will forcefully extend the lead leg. The back foot should be turned over, with the toe dragging on the ground. The pitcher should bring the back leg forward to a standing position. The pitcher should feel a strong pull in the lead leg’s groin, hamstring, and quadriceps. Once the movement is mastered with the lower body, the upper body can be added. The pitcher must remember to stride forward as far as possible, landing on a flex lead leg. Eventually, the pitcher can add 10-15lbs. ankle weights to the back leg to increase resistance during lead leg extension. If the drill is done in pairs, a partner can add resistance by holding on to the back ankle during the front leg extension. The tension can vary and the drill should be done until the groin, hamstring, and quadriceps is fatigue to failure. After mastery, pitchers can incorporate throwing into the drill. If a baseball is added to the drill, the pitcher should release during the extension and drag of the back foot. If a pitcher releases before lead leg extension occurs, the focus point of the drill is lost and bad habits may be formed. Players should thoroughly master the drill and add resistance to the ankle before incorporating a ball.
Lexington Sports Medicine Clinic, Kinetic Chain in Function and Dysfunction.
MacWilliams, B, Choi, T., Perezous, M, Chao, E, McFarland, E. Characteristic Ground Reaction Forces in Baseball Pitching. The American Journal of Sports Medicine, 26(1): 66-71, 1998.
Matsuo, T, Escamila, RF, Fleisig GS, Barrentine, SW, and Andrews, JR. Comparison of kinematic and temporal parameters between different pitch velocity groups. Journal of Applied Biomechanics, 17(1): 1-13, 2001