The old pitching “Balance Drill” is when a pitcher lifts his lift leg and holds the leg in the air, parallel to the ground, for a good amount of time, to work on “Balance.” This drill is extremely outdated in my book because it goes against today’s understanding of explosive mechanics. Velocity is very important in pitching because it gives the pitcher more power over the hitter. This is also what all college and professional scouts are looking for in prospective pitchers.
Balance is an major component of the elite athlete but it must be developed through force production. This is when the athlete pushes force into the ground and then stabilizes the joints to allow for the force to then push back into the body to create movement. This has to do with Newton’s Third Law of Motion that says, To every action there is always an equal and opposite reaction. This stabilization of the joints during this force production is what is considered to be “balance”. The more force the athlete can drive into the ground, while stabilizing their joints to allow for that force to push back, then the more explosive the athlete. This means that performing a drill that requires very little force production, like the old “Balance Drill,” is a total waste of time and limits the athletes ability to develop the motor skills to perform explosive movements, like throwing a hard fastball.
In conclusion, the answer to the question is YES, the old “Balance Drill” will hurt velocity because it is training the athlete develop balance and movement through very little force production and because of pitchers like Aroldis Chapman and Tim Lincecum to name a few we know that the more force applied in the stride phase the more torque created at front foot strike. This torque then transfers into the velocity of the ball.
To learn more about force production and velocity you must read this article called, 3X Force Production is the Driving Force Behind Velocity.