The Kinetic Chain Revisited: New Concepts on Throwing Mechanics and Injury

Abstract

The overhead throwing motion is a complex activity that is achieved through activation of the kinetic chain. The kinetic chain refers to the linkage of multiple segments of the body that allows for transfer of forces and motion. The lower extremities and core provide a base of support, generating energy that is transferred eventually through the throwing arm and hand, resulting in release of the ball. The kinetic chain requires optimal anatomy, physiology, and mechanics and is involved in all 6 phases of overhead throwing: windup, stride, arm cocking, acceleration, deceleration, and follow-through. Breaks or deficits in the kinetic chain can lead to injury or decreased performance. Through an understanding of the mechanics and pathomechanics seen in each phase of throwing, the clinician can better evaluate and screen for potential kinetic chain deficits in the overhead throwing athlete. The purpose of this article is to review the biomechanics of the overhead throwing motion, the role of the kinetic chain in throwing, and the clinical evaluation and management of abnormal throwing mechanics and related injuries.

Exercise prescription for overhead athletes with shoulder pathology: a systematic review with best evidence synthesis

“…Overhead athletic performance is not isolated to a single event or joint. Maximising force development in the large muscles of the core and legs produces more than 51%–55% of the kinetic energy that is transferred to the hand 63. Overhead throwing motion is a complex activity, involving the shoulder, trunk, spine and lumbo-pelvic-hip complex, that is achieved through the activation of the kinetic chain,63 to allow the sequential transfer of forces and motion.…”

“…Maximising force development in the large muscles of the core and legs produces more than 51%–55% of the kinetic energy that is transferred to the hand 63. Overhead throwing motion is a complex activity, involving the shoulder, trunk, spine and lumbo-pelvic-hip complex, that is achieved through the activation of the kinetic chain,63 to allow the sequential transfer of forces and motion. The throwing motion is a fluid, continuous movement that begins with the feet, which provide contact with the ground, maximising the ground reaction force, and creating a stable base for distal arm mobility 63…”

Single-Leg Squat Performance and Reported Pain within Youth Softball Players

“…Such high repetition of a singular movement pattern may lead to overuse injury. Throwing is a complex dynamic movement that requires efficient use of the kinetic chain [7,8].…”

“…Specifically, force is generated in the proximal lower extremity and then transferred thorough the lumbopelvic-hip complex (LPHC), to the distal upper extremity, and on to the ball at release. Trunk musculature contributes to LPHC stability during the overhead throwing motion is important not only for postural control but to also generate and transfer force from the lower extremity to the upper extremity [8]. Due to the unilateral nature of the overhead throw, structural and mechanical asymmetries develop in overhead throwing athletes; meanwhile, such asymmetries may place athletes at a greater risk of injury.…”

“…When considering the overhead throwing motion as a total body dynamic activity, awareness of segmental asymmetries that could result in kinetic chain alterations is needed. As any alteration in the kinetic chain could result in compensations and ultimately injury to the more distal segments in the chain [8].…”