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The incidence of elbow injury experienced by baseball pitchers is on the rise. Biomechanical investigations focusing on the acceleration phase of the pitch have yet to elucidate a singular cause for these injuries. Leading to the question is there an additional significant stress on the elbow during other phases of the pitch? This study sought to determine the magnitude of the elbow varus moment during the deceleration phase of the pitching cycle for the fastball, curveball, slider and change-up. Eighty-seven collegiate-level pitchers were evaluated using motion analysis techniques to determine the magnitude of the elbow varus moment occurring during the deceleration phase. The results indicated that the elbow varus moment during the deceleration phase of the pitch was typically between 40% and 50% of the peak acceleration phase moment and was greatest when throwing a slider. Results also indicated that more pitchers experienced deceleration phase moments in excess of 50% of the acceleration moment when throwing breaking pitches. These moments which are the result of the pitchers' need to rapidly decelerate their arm produce an additional significant elbow varus moment that results in additional stress to the elbow. [ABSTRACT FROM AUTHOR]

Researchers have postulated that the rise in the incidence of pitching injuries is partially due to poor pitching mechanics. A topic that is often debated revolves around the correct positioning of the elbow in relationship to the body. Therefore, this study attempts to understand the associations of vertical or horizontal elbow positon with upper extremity joint moments, and ball velocity, and how elbow position is influenced by trunk position. Motion analysis data from 99 collegiate pitchers were analysed for this study. A random intercept, mixed-effects regression model was used to determine if statistically significant associations existed between elbow position and upper extremity joint moments and ball velocity. Results indicated that visual impressions of the elbow position were highly correlated with trunk position, whereas kinematic definitions of elbow position were correlated to the glenohumeral angle. Visual vertical and horizontal elbow position was associated with increased elbow varus moments (p = 0.001) and ball velocity (p = 0.019), respectively. Whereas kinematic elbow position was not associated with either upper extremity joint moments or ball velocity. Therefore, what coaches visually interpret as an improperly positioned elbow may actually be a combination of lateral lean, anterior tilt, and over rotation of the trunk. [ABSTRACT FROM AUTHOR]