Measuring Eccentric Strength of the Shoulder External Rotators Using a Handheld Dynamometer: Reliability and Validity

Abstract

Context: Shoulder strength assessment plays an important role in the clinical examination of the shoulder region. Eccentric strength measurements are of special importance in guiding the clinician in injury prevention or return-to-play decisions after injury.Objective: To examine the absolute and relative reliability and validity of a standardized eccentric strength-measurement protocol for the glenohumeral external rotators.Design: Descriptive laboratory study. Setting: Testing environment at the Department of Rehabilitation Sciences and Physiotherapy of Ghent University, Belgium.Patients or Other Participants: Twenty-five healthy participants (9 men and 16 women) without any history of shoulder pain were tested by 2 independent assessors using a handheld dynamometer (HHD) and underwent an isokinetic testing procedure.Intervention(s): The clinical protocol used an HHD, a DynaPort accelerometer to measure acceleration and angular velocity of testing 308/s over 908 of range of motion, and a Biodex dynamometer to measure isokinetic activity.Main Outcome Measure(s): Three eccentric strength measurements: (1) tester 1 with the HHD, (2) tester 2 with the HHD, and (3) Biodex isokinetic strength measurement.Results: The intratester reliability was excellent (0.879 and 0.858), whereas the intertester reliability was good, with an intraclass correlation coefficient between testers of 0.714. Pearson product moment correlation coefficients of 0.78 and 0.70 were noted between the HHD and the isokinetic data, showing good validity of this new procedure.Conclusions: Standardized eccentric rotator cuff strength can be tested and measured in the clinical setting with good-toexcellent reliability and validity using an HHD.Key Words: eccentric testing, upper extremity, injury prevention, rehabilitation Key PointsUsing a handheld dynamometer, standardized eccentric rotator cuff strength can be measured in the clinical setting with good to excellent reliability and validity. The eccentric rotator cuff strength test provides important information that is useful for injury prevention, rehabilitation, and performance enhancement.

Eccentric and isometric shoulder rotator cuff strength testing using a hand-held dynamometer: reference values for overhead athletes

“…The order of the tests was randomized between sides and between the procedures, in order to control the procedure for learning effects and fatigue. Each test was repeated three times with a pause in between trials of 20 s [9,11,18]. For the eccentric strength measurement, the protocol of Johansson et al [18] was used.…”

“…Each test was repeated three times with a pause in between trials of 20 s [9,11,18]. For the eccentric strength measurement, the protocol of Johansson et al [18] was used. The subject was in a seated position, feet at shoulder width, the lower back supported against a chair, and held the elbow and shoulder at a position of 90° of abduction and 90° of external rotation (90-90) with support from the examiners hand and forearm.…”

What is the effect of a shoulder-strengthening program to prevent shoulder pain among junior female team handball players?

“…A MicroFET 2 handheld dynamometer (Hoggan Health Industries, Salt Lake, UT, USA) was used to objectively measure the strength. A pilot study to test the inner reliability was not performed, since the intrarater validity and reliability when using a handheld dynamometer are well established in the litterature 24–26…”

Current Concepts in Rehabilitation for Traumatic Anterior Shoulder Instability

“…In terms of rotator cuff strength, an isokinetic ER/IR ratio of 66% or an isometric ER/IR ratio of 75-100% has been advised with the dominant shoulder typically 10% higher than the non-dominant side [12][13][14][15]. Johansson et al demonstrated good to excellent reliability for measuring eccentric external rotation strength using a hand-held dynamometer [36], which we have started to incorporate in our return to sport assessment.…”