Inter- and intra-tester reliability when measuring seated spinal postures with inertial sensors
2014 (English)In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 44, no 5, 732-738 p.Article in journal (Refereed) Published
Prolonged awkward sitting postures may be associated with neck or back pain, but it is often unclear which specific postures cause most problems and which mechanisms that may underlie the pain. In order to increase the knowledge in this field, it seems crucial first of all to be able to analyse, in depth, different seated spinal postures. A problem is however the lack of reliable and direct measurement methods of the posture, especially for sitting. Recently developed systems with inertial sensor attached along the spine have potential for this purpose. The aim of the present study was therefore to test the reliability of using such a system to assess various seated postures. Inter- and intra-tester as well as intra-subject relative reliability was estimated with intra-class correlation coefficient (ICC). Absolute reliability was estimated with standard error of measurement (SEM) and smallest detectable change (SDC). Ten + ten healthy subjects and four testers participated. Three standardised unsupported seated postures (lumbar lordosis, lumbar kyphosis and neutral posture) and two standing postures (neutral and lumbar kyphosis) were evaluated using five sensors attached to the head, the thorax (high and low), the lumbar spine and the pelvis. The ICC for intra-tester reliability ranged from 0.37 to 0.90, SEM 2.5-12.0 degrees, and SDC 7.1-333 degrees where the largest measurement error was from the head. Intra-tester reliability was higher than inter-tester reliability but not as good as intra-subject reliability. The intra-tester absolute reliability was nevertheless not considered sufficient to distinguish smaller differences. The low reliability may depend on inertial sensor size and attachment but also on the tester's accuracy. This study shows that assessing unsupported seated spinal postures with inertial sensors could be performed with higher reliability if done by the same, rather than different, testers. Relevance to industry: Prolonged awkward seated postures at work may be associated with back and neck pain and should therefore be analysed. Inertial sensor units is a promising tool to measure spinal posture. Smaller sensors attached by one skilled tester directly onto the body will most likely improve assessment in the future. (C) 2014 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 44, no 5, 732-738 p.
Biomechanics, Human engineering, Observer variations
IdentifiersURN: urn:nbn:se:umu:diva-96963DOI: 10.1016/j.ergon.2014.06.002ISI: 000344439600015ScopusID: 2-s2.0-84906734375OAI: oai:DiVA.org:umu-96963DiVA: diva2:770707