Lind Carl M, Rhen Ida-Märta, Forsman Mikael
Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden.
Centre for Occupational and Environmental Medicine, Stockholm County Council, 113 65 Stockholm, Sweden.
Bioengineering (Basel). 2025 Jan 9;12(1):50. doi: 10.3390/bioengineering12010050.
Adequate reference procedures for obtaining the reference zero-angle position are important for precise and accurate posture measurements, but few studies have systematically investigated these. A limited number of previous studies suggest differences in accuracy between procedures, with some causing an underestimation of the true arm elevation angle when sensors are taped to the skin. The reliability of commonly used reference procedures for the measurement of the trunk posture is also not well explored, and alternative procedures may improve precision. Based on this identified gap, this study evaluated the test-retest reliability of the N-position (I-pose), i.e., the standard procedure for recording trunk postures, and compared it with two new alternative procedures. Additionally, the accuracy of the N-position for measuring arm elevation angles was compared with one alternative procedure. A total of 40 participants (22 women and 18 men) aged 26-70 years performed the reference procedures in a laboratory setting. Postures were recorded using a smart workwear system equipped with two inertial measurement units (IMUs) embedded in pockets within the workwear. For the trunk posture, the N-position showed a slight lack of test-retest reliability, while one of the alternative procedures demonstrated better test-retest reliability. For the arm posture, the N-position, which does not include lateral trunk inclination, resulted in a substantial underestimation of the arm elevation angle of approximately 15°, which is a novel finding. In contrast, the posture involving trunk inclination closely matched the targeted reference, with a difference of less than 2°. This study underscores the importance of selecting appropriate reference procedures to ensure precise and accurate posture measurements.
获得参考零角度位置的适当参考程序对于精确和准确的姿势测量很重要，但很少有研究对其进行系统调查。此前数量有限的研究表明不同程序在准确性上存在差异，有些程序在将传感器贴于皮肤上时会导致对真实手臂抬高角度的低估。常用的测量躯干姿势的参考程序的可靠性也未得到充分探究，而替代程序可能会提高精度。基于这一已确定的差距，本研究评估了N姿势（I姿势）（即记录躯干姿势的标准程序）的重测可靠性，并将其与两种新的替代程序进行比较。此外，将测量手臂抬高角度的N姿势的准确性与一种替代程序进行了比较。共有40名年龄在26至70岁之间的参与者（22名女性和18名男性）在实验室环境中执行参考程序。使用配备有两个嵌入工作服口袋中的惯性测量单元（IMU）的智能工作服系统记录姿势。对于躯干姿势，N姿势显示出略有不足的重测可靠性，而其中一种替代程序表现出更好的重测可靠性。对于手臂姿势，不包括躯干侧倾的N姿势导致对手臂抬高角度的大幅低估，约为15°，这是一个新发现。相比之下，涉及躯干倾斜的姿势与目标参考密切匹配，差异小于2°。本研究强调了选择合适的参考程序以确保精确和准确的姿势测量的重要性。
