Elbow Biomechanics During Sports: 21st Century Research

Abstract

Injuries to the elbow joint are becoming more and more prominent in today's sporting society. This is largely because of the biomechanical demands during popular sports such as baseball, softball, and tennis; wherein the majority of elbow injuries occur. Implications for injuries in these sports range from overuse to incorrect mechanics, which cause increased loads at the elbow joint. This can be seen in the overhead throwing motion where a large varus torque leads to tensile injuries in the medial elbow and compressive injuries in the lateral elbow. The tennis serve produces large varus torque like in baseball pitching, but significantly less elbow extension velocity and elbow flexion torque. In cricket, elbow biomechanics play a very important role, as the rules prohibit elbow flexion during the arm acceleration of bowling. Windmill softball pitchers were once thought to not be at high risk for injury because of their style of throw. However, studies of windmill pitching reveal rapid kinematics and high kinetic loads that are leading to increased amounts of injuries. To improve on surgical treatment, physical therapy, and even prevention of elbow injuries, one must have a good understanding of the biomechanics of the elbow during these activities. This article presents recent advances in understanding elbow biomechanics during sports, based on studies published since the year 2000.

Biomechanical Performance of Baseball Pitchers With a History of Ulnar Collateral Ligament Reconstruction

“…8 However, cadaveric research has shown that the UCL can provide only about 32 N·m of elbow varus torque. 8,12 Although both biomechanical modeling and cadaveric research have limitations and inaccuracies, these studies support the explanation that peak tension in the UCL is dangerously high when the pitcher’s arm is externally rotated, and repetitive pitching can create tears in the anterior bundle of the UCL.…”

The Clinician’s Guide to Baseball Pitching Biomechanics

“…Typically, the pitching motion is divided into the following 6 phases: windup, stride, arm cocking, arm acceleration, arm deceleration, and follow-through (Figures 1 and 2 and Supplementary Videos 1 and 2). 11,14,15,17,18,19,22,23,24,25,32,34,51,52,54 The windup phase commences when the pitcher begins lifting the lead leg while the hands are held together high at the chest. The windup phase ends when the lead knee has reached its maximum height.…”

“…An additional significant risk factor for increased elbow and shoulder stress is poor pitching mechanics. 1,6,24,25,49,51,53 In the 20th century, throwing mechanics were usually evaluated via the naked-eye or standard 2-dimensional video. Automated tracking technology has changed the way throwing mechanics are analyzed, providing accurate and reliable 3-dimensional (3D) kinematic (motions) and kinetic (forces and torques) measurements.…”