Velocity Spectrum Torque Testing of Shoulder Internal Rotators

Document Type

Article

Publication Date

5-2014

Publication Title

Medicine & Science in Sports & Exercise Supplemental

DOI

10.1249/01.mss.0000495068.00305.d1

ISSN

1530-0315

Abstract

Power is one of the most important components of sports performance. While, there are limited methods to assess upper extremity power as a whole, isolated joint torque can be quantified using isokinetic velocity spectrum testing. There is limited isolated shoulder internal rotator (IR) torque data across the velocity spectrum.

PURPOSE: To perform isokinetic shoulder IR torque testing across the velocity spectrum.

METHODS: Thirty recreationally active and healthy men between the ages of 18-30yrs (1.87±.06m, 80.0±13.6kg) completed shoulder IR isokinetic testing at nine velocities (beginning at 60°/s, increasing by 30°/s, ending at 300°/s). Prior to testing, participants completed a five-minute, moderate intensity warm-up on an arm ergometer. Participants assumed a stabilized supine position adjacent to an isokinetic dynamometer with the arm positioned in 80° shoulder abduction and 90° elbow flexion. Range of motion stops were placed at 80° external rotation (ER) and 60° IR. Subjects were instructed to perform four maximal effort bouts of ER and IR at the nine velocities in a random order through the entire range of motion. A rest period of 40s was required between each test velocity to limit fatigue. The dominant and nondominant shoulders were tested in a randomized order. The average peak torque across the four repetitions at each velocity was computed and subjected to a limb by velocity repeated measures analysis of variance.

RESULTS: Averaged across all velocities, the dominant shoulder demonstrated significantly greater average peak torque compared to the nondominant shoulder (P<.001, 95% CIdiff: 2.5 to 6.4 Nm). Average peak torque significantly decreased (range: 1.7 to 5.1Nm) at each incremental velocity increase until 210°/s. There were no significant average peak torque differences between velocities of 240°/s, 270°/s and 300°/s.

DISCUSSION: Training specificity is important in developing shoulder power for upper extremity athletes. Although most functional activities use the entire kinematic chain, using isolated training of each link is an important part of injury prevention and performance enhancement. Based on these results, we recommend training at 300°/s to replicate sports performance speeds because the same amount of torque was produced at 300°/s compared to 240°/s and 270°/s.

Comments

© 2014 American College of Sports Medicine

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