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Driveline’s Pitching Research Homepage

Pitching Mechanics Research

The Impact of Fatigue on Baseball Pitching Mechanics in Adolescent Male Pitchers

Authors: Erickson, Brandon J; Sgori, Terrance; Chalmers, Peter; Vignona, Patrick; Lesniak, Matthew; Bush-Joseph, Charles; Verma, Nikhil; Romeo, Anthony

This study wanted to determine what kinematic factors changed as pitchers fatigued when throwing a simulated game. Pitching velocity, accuracy and pain levels were also tracked.

Adolescent males aged 13-16 thru a total of 90 pitches broken into groups of 15 pitches. As pitchers threw they experienced more fatigue, more pain and threw at lower velocities. Knee flexion at ball release progressively increased, although the researchers mention that it is likely a clinically insignificant change. Hip-to-shoulder separation significantly decreased as the simulated game went on as well.

Upper arm kinematics remained unchanged throughout, external rotation and total range of motion in the pitching shoulder significantly increased after pitching.

Because pitchers in the study experienced regular pain and fatigue the authors suggested that pain and fatigue may not be reliable measures of an impending injury.

Other interesting points in the studies included: 46% of subjects pitched for multiple teams, 39% pitched for more than 9 months a year, 61% participated in showcases and 11% had returned to the mound after being removed.

Keep in mind there is a big difference between pitchers who are adolescents and those whom are physically mature. It is an interesting finding that even those velocity did slightly decrease the kinematics of the throwing arm remained unchanged.

The Kinetic Chain revisited: New Concepts on Throwing Mechanics and Injury

Authors: Chu, SK; Jayabalan, P; Kibler, WB’ Press, J 

This paper looks at the entire kinetic chain of the pitching motion and breaks the pitching motion down into mechanical phases. Six mechanical phases are defined in the paper. It may be interesting for coaches and athletes to read what the phases the paper claims makes up the pitching motion to compare those to their own opinions.
One issue is the definition of the phases do not take into account the amount of variance that can be found in pitchers deliveries. It is also not clear if the paper suggests that all pitchers should throw exactly like the descriptions of the phases.

 Correlation of Throwing Mechanics with Elbow Valgus Load in Adult Baseball Pitchers

Authors: Aguinaldo, Arnel L; Chambers, Henry

This study examined pitching mechanics of sixty nine adult baseball players to try and determine what mechanics are correlated to increased valgus torque. Valgus torque is the stress put on the elbow, which is believed to cause UCL tears in some athletes.

Elbow valgus torque was most significantly influenced by peak shoulder external rotation, elbow flexion at peak valgus torque and elbow valgus loading rate.

Pitchers who initiated trunk rotation before front-foot contact exhibited significantly more elbow valgus torque than the pitchers who rotating their trunks after front-foot contact.

Elbow valgus torque increased with greater degrees of shoulder external rotation but decreased with more elbow flexion at ball release. It’s expected that higher shoulder external rotation will increase elbow valgus torque, but the finding that valgus stress is decreased with elbow flexion challenges the common belief that the elbow should be straighter during the delivery.

Fourteen of the pitchers threw sidearm. Those pitchers averaged a significantly higher average elbow valgus torque that pitchers who threw overhand. Suggesting pitching sidearm puts more stress on a pitcher’s arm than throwing overhand.