The changes in pitching mechanics and pitch velocity during a seven-inning simulated game in high school baseball pitchers: A prospective descriptive study

ontext. Past studies have described the pitching motion of youth, collegiate, or professional baseball pitchers, as well as the relationship between shoulder mechanics, extended play, and pitch velocity. However, there is little research that has described the changes in the pitching motion and pitch velocity as a result of increasing pitch counts in high school baseball pitchers. Objective. The purpose of this study was to describe how pitching mechanics change, when these changes occur, and the extent of which pitch velocities decline in high school baseball pitchers during a seven-inning simulated game. Design. This study was a prospective descriptive analysis of the pitching motion. The independent variables were a simulated game with 7 innings consisting of 12 pitches per inning and 9 minutes rest between innings. The dependent variables were shoulder, elbow, and trunk inclination angles, pitching mechanics analysis, and pitch velocity. Setting. The Caperton Indoor Practice Facility in Morgantown, WV. Patients and other participants. There were 4 subjects who were members of the boy's varsity baseball team at Albert Gallatin High School. There was also one catcher whose sole purpose was to catch the pitches thrown by the subject. Subjects were obtained by a sample of convenience, 16.25 +/- 0.50 years old, healthy, and had no history of shoulder or elbow pain or surgery within the past six months. Subjects were not included if they met the exclusion criteria of having a concussion in the past six months or a history of concussions that had altered or diminished their ability to balance on one leg. Intervention. Subjects pitched a seven-inning simulated baseball game that took place at the Caperton Indoor Practice Facility. Each subject pitched 7 innings consisting of 12 fastballs per inning from an indoor pitching mound. During the seven 12-pitch innings, two video cameras recorded each subject's 1st, 7th, and 12th pitch of each inning. Foam markers were placed on lateral bony landmarks of the upper and lower extremity that aided in the analysis of joint angles of each subject's pitching motion. A pitching evaluation checklist was also used to identify normal and/or abnormal pitching mechanics. Subjects also had their pitch velocity recorded using a radar gun for every pitch that was thrown. Those pitch speeds were recorded onto a chart and later used to describe how and when a subject's pitch velocity changed as his pitch count increased during the course of the game. Main outcomes measures. Using joint angle measurements, shoulder internal rotation, shoulder external rotation, and shoulder abduction angles will decrease as pitch count increases. Also, elbow flexion and forward trunk tilt angles will decrease as pitch count increases using visual analysis. Lastly, average pitch velocity per inning will decrease as pitch count increases. Results. There was a significant difference within subjects in the shoulder internal rotation angles of Pitch...