Biomedical Engineering Reference
In-Depth Information
Fig. 1
( a ) Subjects performing external and ( b ) internal rotation
2.3
Task
The subject was in a seated position, with supported feet, keeping the hips and knees
at 90 ı flexion. The shoulder evaluated was at 90 ı of humeral elevation and in the
scapular plane supported by the researcher. The subjects performed one task in two
specific conditions concerning velocity: (1) slow axial rotation; (2) fast axial rotation
(figure A). Subjects performed total axial rotation since maximal external (Fig. 1 a)
rotation until maximal internal rotation (Fig. 1 b).
At the first condition, subjects were asked to perform slow motion, keeping the
scapula stable. At the second condition, they performed the movement reproducing
a ballistic one. Both conditions were repeated for three times each. Humeral
axial rotation was described with respect to the scapula, the glenohumeral (HRs)
angles, and with respect to thorax, the thoracohumeral (HRt). Scapular position was
described with respect to the thorax as protraction (Syt), lateral rotation (Sxt) and
spinal tilt (Szt). These angles were recorded at end-range of active fast and slow
(subject self-selected end-of-range).
2.4
Statistics
A mixed-model two-way ANOVA was used to test the main effect of group
(between-group factor) on the three scapular (Syt, Sxt and Szt) and the two humeral
(HRt and HRs) dependent variables, as well as test for an interaction of group and
speed motion (slow vs . fast; within-subjects factor). A bivariate correlation test was
used to describe the relationships between HRt and scapular variables. Another
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