[quote=“laflippin”]Here it is, DM…they used exptl data for 33 subjects to construct kinematic models that they could then use to simulate the effect of changes in arm-angle (shoulder abduction) and trunk tilt on elbow varus force (not valgus force…).
J Appl Biomech. 2006 May;22(2):93-102.
Influence of shoulder abduction and lateral trunk tilt on peak elbow varus torque for college baseball pitchers during simulated pitching.
Matsuo T, Fleisig GS, Zheng N, Andrews JR
Osaka University, ASMI, Univ of Florida
Elbow varus torque is a primary factor in the risk of elbow injury during pitching. To examine the effects of shoulder abduction and lateral trunk tilt angles on elbow varus torque, we conducted simulation and regression analyses on 33 college baseball pitchers. Motion data were used for computer simulations in which two angles-shoulder abduction and lateral trunk tilt-were systematically altered. Forty-two simulated motions were generated for each pitcher, and the peak elbow varus torque for each simulated motion was calculated. A two-way analysis of variance was performed to analyze the effects of shoulder abduction and trunk tilt on elbow varus torque. Regression analyses of a simple regression model, second-order regression model, and multiple regression model were also performed. Although regression analyses did not show any significant relationship, computer simulation indicated that the peak elbow varus torque was affected by both angles, and the interaction of those angles was also significant. As trunk tilt to the contralateral side increased, the shoulder abduction angle producing the minimum peak elbow varus torque decreased. It is suggested that shoulder abduction and lateral trunk tilt may be only two of several determinants of peak elbow varus torque.
Matsuo in 1999 first identified excessive abduction as an issue (although apparently he got it from Chris O’Leary…LOL). Then in 2002 and in 2006 (your article) he showed the interdependency of abduction and trunk tilt in contributing to elbow stress. Matsuo was pretty specific in 1999 on abduction saying varus torque was minimized between 90 and 100 degrees and on trunk tilt in excess of 10 degrees. Werner’s in 2002 backed up Matsuo’s work saying “Increasing the amount of arm abduction was shown to be contributory to increasing the amount of valgus stress at the elbow.”
Bottom line, teaching kids to “get their elbow up”, based on the available research that has been done, is not a good idea.