The effect of walking speed on local dynamic stability is sensitive to calculation methods.
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| Title: | The effect of walking speed on local dynamic stability is sensitive to calculation methods. |
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| Authors: | Stenum, Jan1, Bruijn, Sjoerd M.2,3, Jensen, Bente R.1 brjensen@nexs.ku.dk |
| Source: | Journal of Biomechanics. 2014, Vol. 47 Issue 15, p3776-3779. 4p. |
| Subjects: | Trajectories (Mechanics), Walking speed, Dynamic stability, Acceleration (Mechanics), Time series analysis |
| Abstract: | Local dynamic stability has been assessed by the short-term local divergence exponent (λS), which quantifies the average rate of logarithmic divergence of infinitesimally close trajectories in state space. Both increased and decreased local dynamic stability at faster walking speeds have been reported. This might pertain to methodological differences in calculating λS. Therefore, the aim was to test if different calculation methods would induce different effects of walking speed on local dynamic stability. Ten young healthy participants walked on a treadmill at five speeds (60%, 80%, 100%, 120% and 140% of preferred walking speed) for 3-min each, while upper body accelerations in three directions were sampled. From these time-series, λS was calculated by three different methods using: (a) a fixed time interval and expressed as logarithmic divergence per stride-time (λS-a), (b) a fixed number of strides and expressed as logarithmic divergence per time (λS-b) and (c) a fixed number of strides and expressed as logarithmic divergence per stride-time (λS-c). Mean preferred walking speed was 1.16±0.09 m/s. There was only a minor effect of walking speed on λS-a. λS-b increased with increasing walking speed indicating decreased local dynamic stability at faster walking speeds, whereas λS-c decreased with increasing walking speed indicating increased local dynamic stability at faster walking speeds. Thus, the effect of walking speed on calculated local dynamic stability was significantly different between methods used to calculate local dynamic stability. Therefore, inferences and comparisons of studies employing λS should be made with careful consideration of the calculation method. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Biomechanics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 99423230 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: The effect of walking speed on local dynamic stability is sensitive to calculation methods. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Stenum%2C+Jan%22">Stenum, Jan</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Bruijn%2C+Sjoerd+M%2E%22">Bruijn, Sjoerd M.</searchLink><relatesTo>2,3</relatesTo><br /><searchLink fieldCode="AR" term="%22Jensen%2C+Bente+R%2E%22">Jensen, Bente R.</searchLink><relatesTo>1</relatesTo><i> brjensen@nexs.ku.dk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Biomechanics%22">Journal of Biomechanics</searchLink>. 2014, Vol. 47 Issue 15, p3776-3779. 4p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Trajectories+%28Mechanics%29%22">Trajectories (Mechanics)</searchLink><br /><searchLink fieldCode="DE" term="%22Walking+speed%22">Walking speed</searchLink><br /><searchLink fieldCode="DE" term="%22Dynamic+stability%22">Dynamic stability</searchLink><br /><searchLink fieldCode="DE" term="%22Acceleration+%28Mechanics%29%22">Acceleration (Mechanics)</searchLink><br /><searchLink fieldCode="DE" term="%22Time+series+analysis%22">Time series analysis</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Local dynamic stability has been assessed by the short-term local divergence exponent (λS), which quantifies the average rate of logarithmic divergence of infinitesimally close trajectories in state space. Both increased and decreased local dynamic stability at faster walking speeds have been reported. This might pertain to methodological differences in calculating λS. Therefore, the aim was to test if different calculation methods would induce different effects of walking speed on local dynamic stability. Ten young healthy participants walked on a treadmill at five speeds (60%, 80%, 100%, 120% and 140% of preferred walking speed) for 3-min each, while upper body accelerations in three directions were sampled. From these time-series, λS was calculated by three different methods using: (a) a fixed time interval and expressed as logarithmic divergence per stride-time (λS-a), (b) a fixed number of strides and expressed as logarithmic divergence per time (λS-b) and (c) a fixed number of strides and expressed as logarithmic divergence per stride-time (λS-c). Mean preferred walking speed was 1.16±0.09 m/s. There was only a minor effect of walking speed on λS-a. λS-b increased with increasing walking speed indicating decreased local dynamic stability at faster walking speeds, whereas λS-c decreased with increasing walking speed indicating increased local dynamic stability at faster walking speeds. Thus, the effect of walking speed on calculated local dynamic stability was significantly different between methods used to calculate local dynamic stability. Therefore, inferences and comparisons of studies employing λS should be made with careful consideration of the calculation method. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Biomechanics is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.jbiomech.2014.09.020 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 4 StartPage: 3776 Subjects: – SubjectFull: Trajectories (Mechanics) Type: general – SubjectFull: Walking speed Type: general – SubjectFull: Dynamic stability Type: general – SubjectFull: Acceleration (Mechanics) Type: general – SubjectFull: Time series analysis Type: general Titles: – TitleFull: The effect of walking speed on local dynamic stability is sensitive to calculation methods. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Stenum, Jan – PersonEntity: Name: NameFull: Bruijn, Sjoerd M. – PersonEntity: Name: NameFull: Jensen, Bente R. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: 2014 Type: published Y: 2014 Identifiers: – Type: issn-print Value: 00219290 Numbering: – Type: volume Value: 47 – Type: issue Value: 15 Titles: – TitleFull: Journal of Biomechanics Type: main |
| ResultId | 1 |
