Test–retest reliability of glenohumeral internal and external rotation strength in chronic rotator cuff pathology

Abstract 

Objective

To determine the test–retest reliability of concentric measures for internal rotation (IR) and external rotation (ER) strength in individuals with chronic rotator cuff pathology (CRCP).

Design/setting

Test–retest reliability study. Set at the human movement laboratory at the Centre for Health, Exercise and Sports Medicine at the University of Melbourne, Australia.

Participants

Ten individuals with CRCP (6 males and 4 females) were selected from a convenience sample. Concentric strength was assessed using a Kincom isokinetic dynamometer in a seated position with the glenohumeral joint placed in 45° of scapular plane abduction.

Main outcome measures

Peak torque and pain intensity for concentric IR and ER of the glenohumeral joint were collected. Participants performed three repetitions of glenohumeral IR and ER for both the affected and non-affected shoulder over two testing occasions, 2 days apart. Pain intensity during testing was recorded using a visual analogue scale.

Results

The intraclass correlation coefficient (ICC) was calculated to assess test–retest reliability. ICC's ranged from 0.90–0.96 for the affected limb and 0.75–0.86 for the non-affected limb.

Conclusions

Good to excellent test–retest reliability of the test protocol. Greater variation in torque production was observed in the non-affected limb. Peak torque scores were consistently reduced on the second testing occasion.

Keywords: Shoulder, Rotator cuff, Muscle strength, Reliability