ABF Pitching Mechanics Research

In the ASMI project eleven position movements of the body during the pitching motion were studied for youth and adult pitchers by brightest 1000 lumen flashlight for doctors. Ten of these position movements for the youth pitchers, e.g., stride length, trunk lean, position of the upper arm during the pitch showed no statistical difference from those for top level pitchers. The one exception was the amount the elbow is bent inward (flexed) at the moment the stride foot touches the mound. The great similarity of movements In adults and youth pitchers is underscored by the research findings.
A second part of the research concluded that elbow and shoulder forces were much higher for adult pitchers. Strong muscles and longer limbs combine to increase the velocities of the shoulder, elbow and the ball for adult pitchers. Youth pitchers go through the same patterns at slower velocities with less force.Adult pitchers routinely build strength through conditioning programs; improve body energy systems through running programs; and limit pitches thrown in practice and in games to control the repetitive forces that are part of each pitch. Since young pitchers mimic adult movements and use the same baseball, they should practice similar safeguards such as maintaining a general healthy state with regular exercise, select a throwing (not necessarily pitching) program that doesn’t strain tender connective tissue and growing bones; and be very selective in using weights to build muscles.


ASMI/ABF Research Quantifies Pitching Guidelines

ASMI/ABF Research Quantifies Pitching Guidelines by David Osinski, Glenn Fleisig Ph.D. Stephen Lyman, Ph.D.
Science substantiates limits for youth pitchers Four years of research aimed at identifying the casual factors in youth pitching injuries has lead ASMI/ABF researchers to believe that the type of limitations placed on pitching appearances needs to be changed. Limitations should be maintained to protect the pitcher but they should be based on the number of pitches thrown per game and per season rather than the amount of batters faced or innings pitched.

This reasoning can be corroborated by the anecdotal presence of pitch limitations used in most of North American professional baseball. Some MLB teams suggest a limit of 100 to 110 pitches per game for hard throwing starting pitchers and in their minor league systems they recommend a per game limit of 75 to 90 for rookie league starters. However ASMI/ABF work has produced a body of scientific evidence which goes beyond concepts employed through experience.

Research Design Starting with an all-star competition during the summer of 1997, the ASMI/ABF built a design to elicit information from youth pitchers after each pitching performance. A questionnaire was constructed which asked the pitchers to report any pain, stiffness or injury during the season and solicited other information regarding throwing arm usage, such as other positions played, competition in other leagues, history of arm injury. Over the ensuing three years the questionnaire was refined and improved.

During the 1999 youth season 488 pitchers, ages 9 to 14, from fifteen leagues throughout Alabama were contacted after each performance. Post-game questionnaires totaled 3584. Team coaches filled out a baseline questionnaire on each pitcher and record the number of pitches thrown in each outing. Before the start of the season 172 pitchers were video taped from three angles. The video was analyzed through the use of a mechanics checklist which asked the pitching expert to designate each vital aspect of the pitching motion as a) proper, b) beyond the normal range, c) below the normal range.

Results as of February 2000Pitch Type

Reports of experiencing pain in the shoulder was 52 % more frequent for those pitchers who used the curveball. Reports related to the elbow was only 14% more frequent, suggesting that there was not a statistically significant relationship. This finding seems to go against most anecdotal information related to youth pitching that the elbow is most affected by the curve, but it does support the idea that adding the curve to the tool box of a young pitcher causes potential injury to the shoulder.

Use of the change up decreased reports of pain by 29% in the shoulder and by 12% in the elbow. This finding reinforces past ASMI research which defined the change up in a lower force category than the fastball, curve and slider. In fact use of the change should be a hallmark of young pitchers so that performance can be enhanced and the arm protected for future development. A live fastball, a consistent change up and the ability to control both pitches seems to be ingredients to successful youth pitching over a long career.

Pitch Count

At the 75 pitch mark a noticeable increase in likelihood of pain at both the elbow and the shoulder appeared in the study. Pain reported in the shoulder increased over the baseline by 83% and for the elbow 114% over the baseline. This finding seconds previous years’ research suggesting that young pitchers be limited to approximately 75 pitches per outing. After an outing which brings the pitcher to this fatigue level two to three days rest from pitching should be employed.

Regarding cumulative pitches per season, pitchers reported 75% more incidence of pain in the shoulder and 111% more in the elbow once having reached 450 pitches during the season. If one assumes that pitches per inning averaged nineteen, then pitchers should be monitored closely at the 24 inning mark.


Few statistically significant relationships were found relating pain to improper movements. In the case of the elbow, several aspects related to the movement of the arm were of note. A reduction in likelihood of pain was related to a) backward lean at the balance point (significant); b) early hand separation (significant); c) short-arm swing; d) high elbow flexion at foot contact; e) low shoulder external rotation at foot contact. It seems that if the pitcher can develop a short, simple arm path that doesn’t make the shoulder swing toward right center field (RHP), there might be less likelihood of eventually experiencing pain at the elbow and serious injury.