Publication: Isokinetic clinical assessment of rotator cuff strength in subacromial shoulder impingement

Land, Helen, Gordon, Susan, and Watt, Kerrianne (2017) Isokinetic clinical assessment of rotator cuff strength in subacromial shoulder impingement. Musculoskeletal Science and Practice , 27. pp. 32-39.

http://researchonline.jcu.edu.au/47432/

Abstract

Background: Current conservative management of subacromial shoulder impingement (SSI) includes generic strengthening exercises, especially for internal (IR) and external (ER) shoulder rotators. However, there is no evidence that the strength or the ratio of strength between these muscle groups is different between those with SSI (cases) and an asymptomatic population (controls).

Objective: To identify if isokinetic rotator cuff strength or the ratio of strength is significantly different between cases and controls.

Study Design: Case Control Study.

Method: Fifty one cases with SSI and 51 asymptomatic controls matched for age, gender, hand dominance and physical activity level completed isokinetic peak torque glenohumeral IR and ER testing. Within the SSI group, 31 dominant limbs were symptomatic and 20 non-dominant limbs were symptomatic. IR and ER were measured separately using continuous reciprocal concentric (con) and eccentric (ecc) contraction cycles at a speed of 600 degrees per second and again at 1200 degrees per second. Values of peak torque (PT), relative peak torque (RPT) and ratios were compared using independent t-tests between the SSI and asymptomatic groups.

Results: Significant strength differences between the two groups were present only when the symptomatic SSI shoulder was the dominant shoulder (con ER PT at 600 /second, ecc ER PT at 1200 /second, ecc ER RPT at 1200 /second and ecc IR PT at 600 /second and 1200 /second).

Conclusions: Changes in rotator cuff strength in SSI may be related to limb dominance, which may have implications for strengthening regimes.