Affiliations: [a] Department of Physical Therapy, Sackler Faculty of
Medicine, Tel Aviv Univesity, P.O. Box 39040, Ramat Aviv, 69978 Tel Aviv,
Israel | [b] Jones and Partners, Radiologists, Adelaide, SA 5000,
Australia | [c] Department of Physiotherapy, University of South
Australia, Adelaide, SA 5000, Australia | [d] Department of Physiology, University of South
Australia, Adelaide, SA 5000, Australia
Abstract: Quantitative assessment of supraspinatus (SSp) strength can add
substantially to the understanding of the underlying pathomechanics and
recovery status of this critically important shoulder joint muscle. Since
strength measurement of the SSP is an involved procedure which at times could
be contraindicated, obtaining indirect but well correlated evidence in the form
of muscle dimensional size may be an alternative method. The objective of this
study was therefore to examine the relationship between SSp size and strength
in a group (n =16) of asymptomatic normal male adults.
Strength during rotations, external (ER) and internal (IR), of the shoulder
joint was measured using isokinetic dynamometry. The representative
morphological dimension of the SSp was its width as calculated from
ultrasonographic imaging of the longitudinal cross section. The main findings
indicated a moderate to strong correlation with ER strength (r
=0.65 to 0.85). In contrast, no parallel
association was indicated with respect to IR. Similar patterns were found for
the right and left shoulders. It is concluded that ultrasonography of the SSp
can furnish valuable information about the strength of this muscle in
asymptomatic subjects. However, clinical studies are essential for vindication
of this technique with respect to symptomatic shoulders affected mainly with
rotator cuff dysfunction.
