Turkish Journal of Medical Sciences




Isokinetic strength assessment of the rotator cuff muscle is frequently applied in a variety of shoulder postures, butnone of these consider muscular architecture, which is one of the most important aspects of improving strength development. This studyaimed to examine the test and retest reliability and validity of the muscle architecture-based position (MABP), which is 25° abductionand 20° external rotation, in healthy subjects to be able to select a better isokinetic assessment position for shoulder rotator cuff muscles.Materials and methods: A total of 54 healthy males with a mean age of 21.0 ± 1.2 years and mean body mass index of 22.8 ± 1.7kg/m2 completed an isokinetic measurement session. All of the tests were performed on an IsoMed 2000 isokinetic dynamometerconcentrically and eccentrically for both upper limbs at 60°/s angular velocity. All of the participants completed 3 measurementsessions: the first represented the isokinetic testing and was performed in the scapular neutral position (SNP) (45° shoulder flexion andabduction), the second represented the MABP (25° abduction and 20° ER) for shoulder rotator cuff muscles, and the third representedthe test and retest of the MABP.Results: The correlations between the 2 techniques for assessing concurrent validity ranged from 0.908 to 0.994. The values obtainedfrom the MABP were higher than those obtained in the SNP. There was no systematic bias for any measurements between the MABPand the retest of the MABP (p > 0.05). The intraclass correlation coefficients representing the test and retest reliability results for eachvariable measured with the MABP was higher than 0.98 and this value was considered as excellent reliability.Conclusion: In conclusion, the MABP can be used to assess the isokinetic strength of the rotator cuff muscles safely and confidently,with increased quantities of force being released and measurement at optimal muscle tension.


Muscle architecture, rotator cuff, muscle strength dynamometer, reproducibility of results

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