Relationship Between Humeral Energy Flow During the Baseball Pitch and Glenohumeral Stability

Abstract

Researchers suggest that motion deriving energy from the more proximal segments of the body is important to reduce injury susceptibility. However, limited clinical assessments have been associated with efficient energy flow within a complex movement such as the baseball pitch. This research aimed to determine the relationship between glenohumeral stability as determined by the closed kinetic chain upper extremity stability test and energy transfer into and out of the humerus during the baseball pitching motion. Kinematic and kinetic data were collected at 240 Hz on twenty-four baseball pitchers. Participants performed the closed kinetic chain upper extremity stability test prior to throwing three fastballs at game speed to a catcher with the fastest fastball used for analysis. Spearman’s Rho were used to examine relationships between energy flow in and out of the humerus with glenohumeral stability as determined by the average score and normalized stance width during the closed kinetic chain upper extremity stability test. There was a significant negative correlation between the average score and normalized peak power leaving the humerus (r s[22]=−0.42, p=0.04). This result provides preliminary support for the use of the closed kinetic chain upper extremity stability test as a clinical assessment of a pitcher’s ability to efficiently transfer energy within the upper extremity during the pitch.

Comparison of Trunk and Pelvic Kinematics in Youth Baseball Pitchers With and Without Upper Extremity Pain: A Cross-Sectional Study

“…For motion capture, sensors were attached to the following locations: (1) posterior aspect of the trunk at the first thoracic vertebra spinous process; (2) posterior aspect of the pelvis at the first sacral vertebra; (3)(4) bilaterally, on the flat, broad portion of the acromion on the scapula; (5)(6) lateral aspect of the bilateral upper arm at the deltoid tuberosity; (7)(8) posterior aspect of the bilateral distal forearm; (9) dorsal aspect of the throwing hand, centered on the third metacarpal; (10)(11) lateral aspect of the bilateral upper leg, centered between the greater trochanter and the lateral condyle of the knee; (12-13) lateral aspect of bilateral lower leg, centered between the head of the fibula and lateral malleolus; and ( 14) dorsal aspect of the foot contralateral to pitching arm centered on the second metatarsal. 19,53 A 15th movable sensor attached to a plastic stylus was used for the digitization of bony landmarks.…”

“…BR was measured as the quantified time point halfway between MER and maximal shoulder internal rotation. 4 , 5 , 52 MER and maximal shoulder internal rotation were determined based on the rotation of the upper arm segment about the long axis defined relative to the thorax using a yx ′ y" Euler rotation sequence. 54 , 57 Data were time-normalized to 100% of the time between PKH and BR and analyzed using 1-dimensional statistical parametric mapping (SPM) in the open-source software package SPM1d.…”