Shoulder loading reliability in seated able-bodied subjects

This is the authors' abstract. We don't add key points for this paper.

Shoulder performance and sensorimotor control assessments help to identify shoulder instabilities and document the rehabilitation progress. Testing seated subjects in a position of hand prehension requires less controlled adjustments to maintain body balance in a clinically relevant situation. The objective of this work was to determine the test-retest repeatability of a novel shoulder stability test in seated subjects with the ipsi-lateral hand in prehension during four arm loading conditions. Able-bodied subjects were seated on a rigid chair fixed to a force plate. A horizontally and posteriorly directed force was applied to the hand for four 4 loading conditions ranging from 0 to 3 kg. Ten postural balance parameters were calculated from the center of pressure displacements and its corresponding free moments. Intra-class correlation coefficients were calculated for three consecutive trials and for four loading conditions. Generally, the intra-class correlations values increased gradually with the load and varied from 0.727 to 0.948. Tz values increased non-linearly with the applied load. The test-retest reliability of a new shoulder stability test in seated able-bodied subjects was high with sufficient loading (3 kg) and 3 trials.