Most physicians, trainers, and therapists are accustomed to thinking of open and closed kinetic chain terminology in terms of exercise and its application in rehabilitation protocols. This terminology can also be used to describe the mechanism by which injuries occur. Categorizing upper extremity injuries in this way not only provides vital insight into the mechanism of the injuries and helps identify possible injured structures but also allows the clinician to better develop treatment protocols. In this article, this categorization is applied to common shoulder and elbow injuries to provide insight into the nature of these injuries.
James R. Andrews, James M. Dennison and Kevin E. Wilk
Naiquan Zheng, Glenn S. Fleisig and James R. Andrews
Kevin E. Wilk, Christopher A. Arrigo and James R. Andrews
The use of closed kinetic chain exercise has grown in the past several years. Closed kinetic chain exercises for the lower extremity have been firmly established in the literature and have been strongly recommended as an integral part of rehabilitation of the patient with anterior cruciate ligament injury. While the scientific and clinical rationale for using closed kinetic chain exercise for the lower extremity appears obvious, the scientific rationale for using closed kinetic chain exercise for the upper extremity is less clear. The purpose of this manuscript is to discuss the scientific rationale for closed kinetic chain for the upper extremity patient. In addition, exercise drills to enhance dynamic stability of the glenohumeral joint are discussed, and a rationale for using these exercises for specific glenohumeral joint pathologies is provided. The concepts of closed and open kinetic chain as applied to the lower extremity may not apply to the upper extremity due to the unique anatomical and biomechanical features as well as the function of the shoulder. It is recommended that clinicians use both closed kinetic chain and open kinetic chain exercises when treating the shoulder patient.
Gabrielle G. Gilmer, Jessica K. Washington, Jeffrey R. Dugas, James R. Andrews and Gretchen D. Oliver
Context: Studies have found that a 20% reduction in energy generation from the lumbopelvic-hip complex during overhead throws leads to a 34% increase in load on the shoulder. Objective: The purpose of this study was to assess the effects of lumbopelvic-hip complex stability, via the single leg squat assessment, on throwing mechanics of softball athletes. Design: Prospective cohort study. Setting: Laboratory setting. Participants: A total of 50 softball athletes (164.0 [104.0] cm, 65.6 [11.3] kg, 16.3 [3.8] y, 8.61 [3.62] y of experience) performed 3 overhead throws and a single leg squat on each leg. Intervention: Four stability groups were derived: (1) stable on both legs (bilateral stability), (2) unstable on the throwing side leg (TS instability) and stable on the nonthrowing side leg, (3) unstable on the nonthrowing side leg (NTS instability) and stable on the throwing side leg, and (4) unstable on both legs (bilateral instability). All throws were analyzed across 4 throwing events: foot contact (FC), maximum external shoulder rotation (MER), ball release (BR), and maximum internal shoulder rotation (MIR). Main Outcome Measures: Mann–Whitney U tests revealed significant differences between the bilateral stability and the TS instability groups in trunk flexion at BR; the bilateral stability and the NTS instability groups in trunk flexion at BR, shoulder horizontal abduction at FC, shoulder rotation at FC, and pelvis flexion at MIR; the TS instability and the bilateral instability groups in trunk rotation at FC; and the NTS instability and the bilateral instability groups in trunk flexion at MER and shoulder rotation at FC. Conclusion: These findings demonstrate the different mechanisms in which energy can be lost through lumbopelvic-hip complex instability as evident in throwing mechanics. The findings from this study suggest that the current methods used for classification could act as a tool for coaches, physicians, and athletic trainers when assessing their athletes’ injury susceptibility.
Kevin E. Wilk, Naiquan Zheng, Glenn S. Fleisig, James R. Andrews and William G. Clancy
Closed kinetic chain exercise has become popular in rehabilitation of the ACL patient. While many clinicians agree on the benefits of closed kinetic chain exercise, there is great discrepancy as to which exercises fit this category. This discrepancy stems from the fact that the kinetic chain concept was originally developed using mechanical engineering concepts and not human kinesiology. In this paper, the kinetic chain concept is redefined in a continuum of lower extremity exercises from closed kinetic chain to open kinetic chain. The placement of an exercise in this continuum is based upon joint kinematics, quadriceps and hamstring muscle activity, cruciate ligament stress, and joint weight-bearing load. An understanding of these factors can help the clinician design a comprehensive and effective rehabilitation program for the ACL patient.
Glenn S. Fleisig, Rafael F. Escamilla, James R. Andrews, Tomoyuki Matsuo, Yvonne Satterwhite and Steve W. Barrentine
Kinematic and kinetic aspects of baseball pitching and football passing were compared. Twenty-six high school and collegiate pitchers and 26 high school and collegiate quarterbacks were analyzed using three-dimensional high-speed motion analysis. Although maximum shoulder external rotation occurred earlier for quarterbacks, maximum angular velocity of pelvis rotation, upper torso rotation, elbow extension, and shoulder internal rotation occurred earlier and achieved greater magnitude for pitchers. Quarterbacks had shorter strides and stood more erect at ball release. During arm cocking, quarterbacks demonstrated greater elbow flexion and shoulder horizontal adduction. To decelerate the arm, pitchers generated greater compressive force at the elbow and greater compressive force and adduction torque at the shoulder. These results may help explain differences in performance and injury rates between the two sports.
Rafael F. Escamilla, Glenn S. Fleisig, Steven W. Barrentine, Naiquan Zheng and James R. Andrews
The purpose of this study was to establish and compare kinematic data among four groups of collegiate pitchers who threw the fastball (FA), change-up (CH), curveball (CU), and slider (SL). Twenty-six kinematic parameters at lead foot contact, during the arm-cocking and arm acceleration phases, and at ball release were measured for 16 collegiate baseball pitchers. Approximately 60% of these parameters showed significant differences among the four pitch variations. The greatest number of differences (14 of 26) occurred between the FA and CH groups, while the fewest differences (2 of 26) occurred between the FA and SL groups. The CH group had the smallest knee and elbow flexion at lead foot contact and the greatest knee and elbow flexion at ball release. During the arm-cocking and arm acceleration phases, peak shoulder, elbow, and trunk angular velocities were generally greatest in the FA and SL groups and smallest in the CH group. At ball release the CH group had the most upright trunk and the greatest horizontal shoulder adduction, while the CU group had the most lateral trunk tilt. Understanding kinematic differences can help a pitcher select and learn different pitches and can help a batter learn how to identify different pitches.
Tomoyuki Matsuo, Glenn S. Fleisig, Naiquan Zheng and James R. Andrews
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.
Yungchien Chu, Glenn S. Fleisig, Kathy J. Simpson and James R. Andrews
The purpose of the current study was to identify the biomechanical features of elite female baseball pitching. Kinematics and kinetics of eleven elite female baseball pitchers were reported and compared with eleven elite male pitchers. Results suggested that females share many similarities with males in pitching kinematics, with a few significant differences. Specifically, at the instant of stride foot contact, a female pitcher had a shorter and more open stride and less separation between pelvis orientation and upper torso orientation. From foot contact to ball release, a female pitcher produced lower peak angular velocity for throwing elbow extension and stride knee extension. Ball velocity was lower for the female. Foot contact to ball release took more time for a female pitcher. Maximal proximal forces at the shoulder and elbow joints were less for a female pitcher.
David F. Stodden, Glenn S. Fleisig, Scott P. McLean and James R. Andrews
To reach the level of elite, most baseball pitchers need to consistently produce high ball velocity but avoid high joint loads at the shoulder and elbow that may lead to injury. This study examined the relationship between fastball velocity and variations in throwing mechanics within 19 baseball pitchers who were analyzed via 3-D high-speed motion analysis. Inclusion in the study required each one to demonstrate a variation in velocity of at least 1.8 m/s (range 1.8–3.5 m/s) during 6 to 10 fastball pitch trials. Three mixed model analyses were performed to assess the independent effects of 7 kinetic, 11 temporal, and 12 kinematic parameters on pitched ball velocity. Results indicated that elbow flexion torque, shoulder proximal force, and elbow proximal force were the only three kinetic parameters significantly associated with increased ball velocity. Two temporal parameters (increased time to max shoulder horizontal adduction and decreased time to max shoulder internal rotation) and three kinematic parameters (decreased shoulder horizontal adduction at foot contact, decreased shoulder abduction during acceleration, and increased trunk tilt forward at release) were significantly related to increased ball velocity. These results point to variations in an individual's throwing mechanics that relate to pitched ball velocity, and also suggest that pitchers should focus on consistent mechanics to produce consistently high fastball velocities. In addition, pitchers should strengthen shoulder and elbow musculature that resist distraction as well as improve trunk strength and flexibility to maximize pitching velocity and help prevent injury.