What is Baseball Internal Pronation?

Internal Pronation (IP) is the intenal rotation of the throwing hand after pitch release. It is the culmination of the kinetic chain reaction’s entire energy load being released into the pitch.

Acceleration needs a decelerative reaction – which is Internal Pronation. Higher velocity pitchers often have more IP than slower velocity pitchers because more energy is being released by high velo arms. Protective Reflex Response (PRR) uses IP to decelerate both the throwing elbow and shoulder. But PRR is SUBCONSCIOUS and VeloPRO understands this.


Internal pronation must be accompanied with extension of the throwing arm over the front side. If such does not occur, there is a shorter deceleration path (for the arm) that creates a “rebounding” effect in the arm. Pitchers whom do not finish properly often have shorter decel arm paths that experience this “rebounding effect”. This is energy trying to escape the body quicker than the movement plane alotted. 

If Internal Pronation is not in proportion to energy loads, injury can occur because there is no equal and opposite reaction to the load. Additionally, it has been found that the upper half of a pitcher will tilt sideways due to the centripical force generated from Internal Pronation. This aids energy dissipation.

VeloPRO  training harnesses connect the entire kinetic chain reaction (KCR) through dynamic balance. This keeps PRR synced – ensuring more power and velocity.