title: Using horizontal heel displacement to identify heel strike instants in normal gait.
abstract: Heel strike instants are an important component of gait analyses, yet accurate detection can be difficult without a force plate. This paper presents two novel techniques for kinematic heel strike instant (kHSI) detection which examined maximal resultant horizontal heel displacement (HHD). Each of these HHD techniques calculates HHD from a selected reference location of either the stance ankle or stance heel to the swing heel. The proposed techniques, along with other previously established techniques, were validated against a 10N force plate threshold. Fifty-four healthy adults walked overground at both normal and fast speeds while wearing athletic shoes. The reported true and absolute errors were as low as 3.2 (4.4) and 5.7 (3.4)ms, respectively, across 8678kHSI when using the stance ankle as a reference, which significantly outperformed (p<0.0001) the established techniques. Gait speed was shown to have a significant effect (p<0.0001) on HHD-determined kHSI, as well as the three other techniques evaluated, highlighting the need for condition-specific identification of kHSI.
authors.affiliation: Liberty Mutual Research Institute for Safety, Center for Physical Ergonomics, 71 Frankland Road, Hopkinton, MA 01748, USA. Electronic address: jacob.banks@libertymutual.com.
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Banks
authors.affiliation: Liberty Mutual Research Institute for Safety, Center for Physical Ergonomics, 71 Frankland Road, Hopkinton, MA 01748, USA. Electronic address: wen.chang@libertymutual.com.
authors.forename: Wen-Ruey
authors.initials: WR
authors.lastname: Chang
authors.affiliation: Liberty Mutual Research Institute for Safety, Center for Physical Ergonomics, 71 Frankland Road, Hopkinton, MA 01748, USA. Electronic address: xu.xu@libertymutual.com.
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Industrial Engineering and Engineering Management, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC. Electronic address: max.chang@ie.nthu.edu.tw.
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Chang
mesh_terms: D061725:Accelerometry / Q000706:statistics & numerical data; D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006365:Heel / Q000502:physiology*; D006801:Humans; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D012775:Shoes; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*
keywords: Comparison; Gait events; Overground; Stance; Walking speed