Pelvis and Torso Kinematics and Their Relationship to Shoulder Kinematics in High-School Baseball Pitchers

Abstract

It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the pitching motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the pitching motion. However, although pelvis and torso kinematics throughout the pitching motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch.

Kinematics and Kinetics of Youth Baseball Catchers and Pitchers

“…Sensors were attached to the following locations: (1) the posterior/medial aspect of the torso at C7; (2) posterior/medial aspect of the pelvis at S1; (3-4) bilateral distal/posterior aspect of the upper arm; (5) the flat, broad portion of the acromion of the scapula; (6-7) bilateral distal/posterior aspect of the forearm; (8-9) bilateral distal/posterior aspect of the lower leg; and (10-11) bilateral distal/posterior aspect of the upper leg [4,[13][14][15][16]. A twelfth sensor was attached to a stylus that was used for digitization of the bony landmarks described by the International Shoulder Group of the International Society of Biomechanics [17].…”

“…Raw data were independently filtered along each global axis using a 4th order Butterworth filter with a cutoff frequency of 13.4 Hz [4,15]. Neutral stance was the Y-axis in the vertical direction; horizontal and to the right of Y was the X-axis; and posterior was the X-axis [16].…”

“…This estimate was required because we did not have the capability to track the movement of the ball. This method to estimate ball release has been used previously in the throwing literature using electromagnetic tracking, but has yet to be validated [4,5,8]. Additionally, kinetics were investigated within the phases of the events: Phase 1 (cocking; FC to MER), Phase 2 (acceleration; MER to BR) and Phase 3 (deceleration; BR to MIR).…”

“…To date, a majority of the available data dedicated to biomechanics of throwing has focused on youth pitchers [1][2][3][4]. However, there is another position that requires more throws than the pitcher, the catcher [5].…”

A study of selected biomechanical variables as a factor of hitting performance among softball players

“…Hitting a baseball: biomechanical description [4] . Pelvis, torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers [5] .…”