Control of posture during tasks representing common work-related postures – a reliability study

Abstract

Assessment of control of posture using a task battery that represents work-related postural conditions is highly recommended for providing a comprehensive understanding of collective postural demands. However, dearth of evidence exists on the reliability of a task battery, thus precluding its use as an outcome measure in field research. This study investigated the intrasession reliability and systematic variation of force plate derived centre of pressure (COP) measures obtained during repeated performance of a task battery (lifting task, limits of stability and bipedal and unipedal stance). COP signals obtained during each task performance were processed to derive various time-domain COP measures. Statistical analyses revealed that 13 of the 19 COP measures displayed excellent relative (ICC_(2,3) ≥ 0.75) and acceptable absolute reliability (SEM%: ≤ 10). Although COP measures displayed systematic variation, the differences were less or equal to the measurement error, except COP measures of unipedal stance and limits of stability. The chosen task battery is reliable and can be used for comprehensive evaluation of control of posture, in both field and laboratory research.

Practitioner Summary: Repeated evaluation of multiple tasks together sequentially could introduce measurement variability. This study investigated intrasession reliability of a task battery representing common work-related postures. The chosen task battery was found to be reliable with acceptable measurement error and can be used in field research settings for evaluation of control of posture.

Keywords::

• task battery
• postural control
• reliability
• standard error of measurement
• centre of pressure

Acknowledgements

The authors acknowledge the technical help provided by Dr Allan Carman (Auckland University of Technology), Dr Daniel Cury Ribeiro and Mr Bruce Knox (School of Physiotherapy, University of Otago).

Disclosure statement

There are no conflicts of interest concerning this study.

Supplemental material

The underlying research materials for this article can be accessed at http://dx.doi.org/10.1080/00140139.2014.994566.