Article

When investigating shoulder kinematics, it may be necessary to limit shoulder
joint angles at a specific level. Previous studies used external frames or
external surfaces to assist the participant to reach the shoulder joint angles of
interest. The accuracy of these methods, however, has not yet been investigated.
In the current study, an external frame was designed to assist in maintaining
specific shoulder postures in a wide range.
The three degrees of freedom of
rotation of the proposed frame were designed to be consistent with the
description of shoulder joint angles recommended by the International Society of
Biomechanics. Six participants used this frame to perform 118 different shoulder
postures. The reference joint angles measured by a motion tracking system were
compared with the frame-defined angles. The angle differences among all the
participants ranged from 12.7 degrees to 85.6 degrees , with an average of 32.2
degrees (SD 15.1 degrees ) across all postures. For the postures with elevation
angles on or below horizontal, the average angle difference was 23.7 degrees (SD
8.5 degrees ). Findings suggest that errors exist when using an external frame to
assist in reaching specific shoulder postures. Error is minimized at elevation
angles close to -30 degrees , and the performance is poor for extreme shoulder postures.
CI - Copyright (c) 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Langue : ANGLAIS