Having recently read “Gender Differences Between Muscle Activation and Onset of the Four Subdivisions of Trapezius During Humerothoracic Elevation,” some interesting thoughts come to mind. The study showed, in normal subjects, different activation timings and overall use of different portions of the trapezius muscle in men and women. In general, women tend to activate lower trap first, but use more overall trapezius firing than men throughout scaption. Men, on the other hand, tend to activate more of the acromion/scapular descending fibers to stabilize the GH complex initially, then have less global activation of the trapezius during full elevation.
This brings to mind a couple things. 1. Should patterns in “normals” influence our treatment in “non-normals?” In treating women, should we look more at lower trap activation vs. looking more at AC/SC joint mechanics in men? If not, what do we have to go on to restore “normal function?” Patients in previous studies have been shown to be able to selectively activate different subdivisions of the trapezius- should this be a part of our training? 2. This brings to mind the bigger question of “What is normal?” Should we strive for symmetry, not only between sides of the body, but between patients? Does every patient need scapulohumeral rhythm to be a certain ratio to be functional? The push for functional over impairment gains helps to prioritize these treatments. With dwindling reimbursement and the need to return to function quickly, are we setting people up for failure down the road by rushing to functional exercises over tissue specific exercises? The balance of impairment vs. function may swing a little far to each side every so often. The practitioner who can marry these two ideas well is the autonomous practitioner of the future.
Link to the article abstract: http://www.ncbi.nlm.nih.gov/pubmed/24139664