Journal of Orthopaedic & Sports Physical Therapy - Charles J. Dillman, PhD

Stretch-Shortening Drills for the Upper Extremities: Theory and Clinical Application

Mon, 08 Sep 2008 00:00:00 EST

Kevin E. Wilk, Michael L. Voight, Michael A. Keirns, Vern Gambetta, Charles J. Dillman, James R. Andrews

Enhanced athletic performance emphasizes the muscle's ability to exert maximal force output in a minimal amount of time. Exaggerated maximal muscular force develops due to athletic movements producing a repeated series of stretch-shortening cycles. The stretch-shortening cycle occurs when elastic loading, through an eccentric muscular contraction, is followed by a burst of concentric muscular contraction. A form of exercise called plyometrics employs a quick, powerful movement involving a prestretch of the muscle, followed by a shortening, concentric muscular contraction, thus utilizing the stretch-shortening muscular cycle. The literature contains numerous references to plyometric training for the lower extremity, but there is a lack of information on the upper extremity plyometric program. Overhead activities, such as throwing, necessitate elastic loading to produce maximal, explosive, concentric muscular contractions. Plyometric exercise employs the concept of the stretch-shortening muscular cycle. The rehabilitation concept of specificity of training suggests plyometric exercise drills should be performed by the throwing athlete. This paper discusses the basic neurophysiological science and theoretical basis for plyometric exercise, and it describes an upper extremity stretch-shortening exercise program for the throwing athlete.

J Orthop Sports Phys Ther 1993;17(5):225-239.

Key Words: stretch-shortening cycle, exercise, muscle spindle

Biomechanics of the Elbow during Baseball Pitching

Mon, 08 Sep 2008 00:00:00 EST

Sherry L. Werner, Glenn S. Fleisig, Charles J. Dillman, James R. Andrews
By understanding pitching biomechanics, therapists can develop better preventive and rehabilitative programs for pitchers. The purpose of this study was to quantify and explain the joint motions, loads, and muscle activity that occur at the elbow during baseball pitching. Seven healthy, adult pitchers were examined with synchronized high-speed video digitization and surface electromyography. Elbow extension before ball release corresponded with a decrease in biceps activity and an increase in triceps activity. A varus torque of 120 Nm, acting to resist valgus stress, occurred near the time of maximum shoulder external rotation. Previous cadaveric research showed that the ulnar collateral ligament by itself cannot withstand a valgus load of this magnitude. Triceps, wrist flexor-pronator, and anconeus activity during peak valgus stress suggests that these muscles may act as dynamic stabilizers to assist the ulnar collateral ligament in preventing valgus extension overload.

J Orthop Sports Phys Ther 1993;17(6):274-278.

Key Words: biomechanics, elbow, baseball pitchers

Biomechanics of Pitching with Emphasis upon Shoulder Kinematics

Mon, 08 Sep 2008 00:00:00 EST

Charles J. Dillman, Glenn S. Fleisig, James R. Andrews
The American Sports Medicine Institute conducts research to increase understanding of mechanisms involved in upper extremity injuries to throwing athletes. This paper presents a qualitative overview of pitching and a detailed quantitative description of arm motion about the shoulder during this highly dynamic activity. Data on kinematics of arm motions about the shoulder are presented for 29 elite throwers. The major motion about the shoulder is external/internal rotation. Scapulothoracic and glenohumeral flexibility permit the arm to reach an externally rotated position of 175°. Approximately 30 msec before release, the arm internally rotates 80°, reaching peak angular velocities near 7,000°/sec. In rehabilitation of injured throwers, there is a need to appreciate the highly dynamic nature of this skill and to attempt to simulate these dynamic motions and loads as part of the final phase of treatment before the athlete returns to competition.

J Orthop Sports Phys Ther 1993;18(2):402-408.

Key Words: shoulder kinematics, biomechanics, pitching

Rehabilitation for the Overhead Athlete

Mon, 08 Sep 2008 00:00:00 EST

Robert Litchfield, Richard Hawkins, Charles J. Dillman, John Atkins, Gene Hagerman
Rehabilitation of the shoulder of the overhead athlete has undergone significant changes during the past few years. This article illustrates shoulder problems related to repetitive overhead activities, such as throwing. Additionally, we present basic science contributions in this area, principles of shoulder rehabilitation, and a comprehensive rehabilitation program for the symptomatic or asymptomatic athlete based on these principles.

J Orthop Sports Phys Ther 1993;18(2):433-441.

Key Words: shoulder, throwing, rehabilitation

Quantification of Elastic Resistance Knee Rehabilitation Exercises

Mon, 05 Feb 2007 09:45:00 EST

Robert A. Hintermeister, Michael J. Bey, Gregory W. Lange, J. Richard Steadman, Charles J. Dillman

Elastic resistance exercises are frequently used for knee rehabilitation following injury and/or surgery. The evidence supporting this mode of rehabilitation is primarily anecdotal, and no biomechanical assessment of elastic resistance exercises has been previously published. The purpose of this project was to quantify muscle activation levels, knee joint angles, and applied force during 5 rehabilitation exercises utilizing an elastic resistance device. Twelve subjects with no previous knee injury performed double knee dip, hamstring pull, leg press, single knee dip, and side-to-side jump exercises while sagittal plane kinematics, applied force from the elastic resistance device, and electromyographic activity of 8 lower extremity muscles were collected. The muscle activation patterns suggest a progressive continuum of rehabilitation exercises that can be applied to nonoperative injuries as well as anterior cruciate ligament reconstructions.

J Orthop Sports Phys Ther. 1998;28(1):40-50.

Key Words: rehabilitation, knee, biomechanics

Electromyographic and Kinematic Analysis of Graded Treadmill Walking and the Implications for Knee Rehabilitation

Mon, 05 Feb 2007 09:45:00 EST

Gregory W. Lange, Robert A. Hintermeister, Theodore Schlegel, Charles J. Dillman, J. Richard Steadman

Muscle activity, joint angles, and heart rate during uphill walking were compared for application in knee rehabilitation. The objectives of this study were to quantify muscle activation levels at different treadmill grades and to determine the grade(s) at which knee range of motion would not further compromise the joint. Average and peak electromyographic activity of the quadriceps (vastus medialis oblique and vastus lateralis) and hamstrings [biceps femoris and medial hamstrings (semimembranosus/semitendinosus)] were recorded during walking at 0%, 12%, and 24% grade. Six subjects (age = 28.5 ± 3.7 years, stature = 1.79 ± .05 m, and mass = 74.7 ± 7.9 kg) walked at self-selected speeds at each grade while ankle, knee, and hip angles, heart rate, and electromyographic activity (surface electrodes) were recorded. Maximum voluntary contractions provided a relative reference for the electromyographic activity during walking. Average and peak electromyographic activity increased significantly across grades for the vastus medialis oblique (125 and 154%), vastus lateralis (109 and 139%), and biceps femoris (53 and 46%), but remained similar for the medial hamstrings. Maximum knee flexion at heel strike increased significantly with grade. Despite decreased self-selected speeds with increasing grade, there were significant increases in heart rate across grades. The results of this study provide a basic understanding of the quadriceps and hamstrings activity levels, lower extremity joint range of motion, and cardiovascular requirements of graded treadmill walking in normal subjects. The results also suggest that a grade just greater than 12% may be most beneficial for knee rehabilitation to minimize patellofemoral discomfort or potential strain on the anterior cruciate ligament. The benefits achieved through this functional activity encourage its implementation in rehabilitation and provide a basis for comparison with injured patients.

J Orthop Sports Phys Ther. 1996;23(5):294-301.

Key Words: knee, rehabilitation, electromyography, gait