Journal of Orthopaedic & Sports Physical Therapy - Gary L. Soderberg, PT, PhD, FAPTA

Shoulder Internal and External Rotation Peak Torque Production through a Velocity Spectrum in Differing

Gary L. Soderberg, M.J. Blaschak
The purpose of this study was to explore alternative positions for isokinetic testing of shoulder internal and external rotation. Peak torque of shoulder internal and external rotation was measured with a CybeP dynamometer in 20 normal young right-handed males. Peak torques of subjects' right shoulders were measured in six different shoulder positions and three different velocities (60, 180, and 300°/sec). Each subject made three movements at each of the 18 position/velocity combinations and a mean peak torque was found for each combination. Differences in peak torque for internal and external rotation due to position and velocity were tested separately with a 2-way ANOVA and Duncan Multiple Range Test (p = 0.05). Peak torque values were significantly different among the three velocities for all test positions. Significant differences were found among the six test positions. Although the highest peak torques were significantly greater than the lowest, there were no consistent differences between the Cybex recommended positions and the alternative positions.

J Orthop Sports Phys Ther 1987;8(11):518-524.

Surface Electromyographic Analysis of Exercises for the Trapezius and SerratusAnterior Muscles

Robert A. Donatelli, Richard A. Ekstrom, Gary L. Soderberg
Study Design: This study used a prospective, single-group repeated-measures design to analyze differences between the electromyographic (EMG) amplitudes produced by exercises for the trapezius and serratus anterior muscles. Objective: To identify high-intensity exercises that elicit the greatest level of EMG activity in the trapezius and serratus anterior muscles. Background: The trapezius and serratus anterior muscles are considered to be the only upward rotators of the scapula and are important for normal shoulder function. Electromyographic studies have been performed for these muscles during active and low-intensity exercises, but they have not been analyzed during high intensity exercises. Methods and Measures: Surface electrodes recorded EMG activity of the upper, middle, and lower trapezius and serratus anterior muscles during 10 exercises in 30 healthy subjects. Results: The unilateral shoulder shrug exercise was found to produce the greatest EMG activity in the upper trapezius. For the middle trapezius, the greatest EMG amplitudes were generated with 2 exercises: shoulder horizontal extension with external rotation and the overhead arm raise in line with the lower trapezius muscle in the prone position. The arm raise overhead exercise in the prone position produced the maximum EMG activity in the lower trapezius. The serratus anterior was activated maximally with exercises requiring a great amount of upward rotation of the scapula. The exercises were shoulder abduction in the plane of the scapula above 120° and a diagonal exercise with a combination of shoulder flexion, horizontal flexion, and external rotation. Conclusion: This study identified exercises that maximally activate the trapezius and serratus anterior muscles. This information may be helpful for clinicians in developing exercise programs for these muscles.

J Orthop Sports Phys Ther. 2003;33(5):247-258.

Key Words: scapula, shoulder, strength, upper extremity

Electromyographic Analysis of Selected Lower Extremity Musculature in Normal Subjects During Ambulation With and Without a Protonics� Knee Brace

Gina Y. Diaz, Darren H. Averett, Gary L. Soderberg

Often, braces are an integral part of treatment programs for patients with pathology of the knee joint. Little evidence exists, however, as to the effect of braces on muscle function. The purpose of this investigation was to compare electromyography (EMG) from 6 lower extremity muscles during level walking without the Protonics™ knee brace and with the brace at 8 resistance settings. Surface electrodes were placed on 1 lower extremity of 19 subjects (ages=21-57) to evaluate EMG activity during ambulation with and without the knee brace. Data were normalized to maximum voluntary contractions and averaged across cycles. There was a significant increase in muscle activity of the rectus femoris, vastus medialis, and vastus lateralis muscles when the brace resisted knee extension and was set at the level of 9. Significantly higher EMG levels also occurred in the vastus lateralis and vastus medialis with the extension module set at level 6 when compared with the no brace trial and resistance levels set at 6 and 2 with the flexion module. In this normal population, there was an increase in activity of selected muscles when the brace was set at the highest resistance settings. These data serve as a guide for clinicians when considering incorporation of a brace of this type into patient management.

J Orthop Sports Phys Ther. 1996;26(6):292-298.

Key Words: knee brace, resistance, electromyography, walking