Dynamic stability of the elbow: Electromyographic analysis of the flexor pronator group and the extensor group in pitchers with valgus instability

Ultrasonographic Assessment of the Flexor Pronator Muscles as a Dynamic Stabilizer of the Elbow Against Valgus Force

“…Several electromyographic studies have shown that the FPMs originating on the MEC, such as the PT, the flexor carpi radialis (FCR), the FDS, and the FCU, demonstrated very high activity during the late cocking and acceleration phases 3,6,7,12) . Glousman et al 6) stated that the PT had decreased activity in pitchers with MUCL insufficiency, and Hamilton et al 7) reported that there was an increase in activation of the extensor supinator muscles and a decrease in FPM activation in injured pitchers during the acceleration phase.…”

The Effect of Medial Collateral Ligament Repair Tension on Elbow Joint Kinematics and Stability

“…The influence of the flexor-pronator mass on the stability of the MCL-deficient elbow was not evaluated in this study but has been reported by others. 40,41 In another in vitro cadaveric study, Jensen et al found that 25 N of MCL repair tension successfully restored native valgus laxity with and without the radial head. 42 The gravity-loaded motion simulator used in the current study complements their use of a constant valgus moment of 0.75 N m to describe the kinematics of the elbow during passive and active flexion.…”

The role of the elbow musculature, forearm rotation, and elbow flexion in elbow stability: An in vitro study

“…Glousman et al 15 showed decreased activity in the pronator teres muscle and increased activity in the extensor carpi radialis longus and brevis muscles in UCL-deficient pitchers with electromyographic analysis and suggested that asynchronous muscle activity may predispose the elbow to this injury. Hamilton et al, 16 in another electromyographic study of pitchers with UCL injury, found decreased activity in the FCU muscle compared with normal pitchers. It is unknown whether flexor-pronator mass weakness is a causative factor or is the result of valgus elbow instability.…”