Reliability of centre of pressure, plantar pressure, and plantar-flexion isometric strength measures: A systematic review

Abstract

Background: Centre of pressure (COP), plantar pressure (PP), and plantar-flexion isometric strength (PF_isom) are often examined in relation to postural control and gait.

Research question: Our aim was to systematically review and quality appraise articles addressing the reliability of COP and PP measures in static stance and PF_isom measures.

Methods: Three electronic databases (SCOPUS®, SportDISCUS™, and PubMed) were searched and supplemented by a manual search. Peer-reviewed original research on the reliability of COP, PP, and PF_isom in healthy adults (≥18 years) was included. Quality appraisal was done according to the updated COnsensus-based Standards for the selection of health Measurement INstruments reliability checklist. Data regarding study characteristics, test protocols, outcome measures, and reliability metrics were extracted.

Results: Forty articles met inclusion and were assessed for their methodological quality. Only four articles (10%) obtained uppermost quality scores. From the reviewed studies, the most reliable measures were: COP sway area and path length; PP mean pressure, percentage body weight distribution, and contact area; and PF_isom peak torque and force. Although these measures generally exhibited good-to-excellent relative reliability based on correlation coefficients, absolute reliability based on typical errors were not always optimal (variation > 10%). Literature on PP reliability was scarce (n = 2).

Significance: Our findings highlight the need for better quality methodological reliability studies to be undertaken to make stronger inferences about the reliability of COP, PP, and PF_isom measures. The most reliable measures based on the current review are: COP sway area and path length; PP mean pressure, percentage of body weight distribution, and contact area; and PF_isom peak torque and peak force. These measures are the ones that should be selected preferentially in clinical settings, bearing in mind that their typical errors might be suboptimal despite exhibiting strong relative reliability.

Keywords: Balance; Centre of pressure; Plantar pressure; Psychometric properties; Triceps surae.