Relationship of Throwing Arm Mechanics and Interval Thorwing Distance in High School Baseball Players

Ninety-five high school baseball players (16 ± 1 years; 75 ± 13 kg; and 178 ± 20 cm) threw from flat-ground at distances of 9 m, 18 m, 27 m, 37 m, and 46 m while wearing a motusBASEBALL sensor (Motus Global, Massapequa, NY USA). Linear mixed-effects models and likelihood ratio tests were utilized to estimate the within-subject relationship between throwing distance and arm slot, arm speed, shoulder rotation, and elbow varus torque. Increases in throwing distance were accompanied by significant increases in varus torque ( 2 = 3509, p<0.01), arm speed ( 2 = 5144, p<0.01), and shoulder external rotation ( 2 = 3277, p<0.01) and significant decreases in arm slot ( 2 = 952, p<0.01). The use of longer distances for training and conditioning are shown to be beneficial in increasing shoulder rotation and arm speed; however, precaution needs to be taken when reaching maximum distances as there is a subsequent increase in elbow varus torque.