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dc.contributor.authorMoore, Isabel
dc.contributor.authorAshford, Kelly
dc.contributor.authorCross, Charlotte
dc.contributor.authorHope, Jack
dc.contributor.authorJones, Holly
dc.contributor.authorMcCarthy-Ryan, Molly
dc.date.accessioned2019-11-08T15:25:31Z
dc.date.available2019-11-08T15:25:31Z
dc.date.issued2019-11-04
dc.identifier.citationMoore, I.S., Ashford, K., Cross, C., Hope, J., Jones, H.S.R. and McCarthy-Ryan, M.F. (2019) 'Humans optimise ground contact time and leg stiffness to minimise the metabolic cost of running', Frontiers in Sports and Active Living, 1, https://doi.org/10.3389/fspor.2019.00053en_US
dc.identifier.urihttp://hdl.handle.net/10369/10827
dc.descriptionArticle published in Frontiers in Sports and Active Living available open access at https://doi.org/10.3389/fspor.2019.00053en_US
dc.description.abstractTrained endurance runners appear to fine-tune running mechanics to minimize metabolic cost. Referred to as self-optimization, the support for this concept has primarily been collated from only a few gait (e.g., stride frequency, length) and physiological (e.g., oxygen consumption, heart rate) characteristics. To extend our understanding, the aim of this study was to examine the effect of manipulating ground contact time on the metabolic cost of running in trained endurance runners. Additionally, the relationships between metabolic cost, and leg stiffness and perceived effort were examined. Ten participants completed 5 × 6-min treadmill running conditions. Self-selected ground contact time and step frequency were determined during habitual running, which was followed by ground contact times being increased or decreased in four subsequent conditions whilst maintaining step frequency (2.67 ± 0.15 Hz). The same self-selected running velocity was used across all conditions for each participant (12.7 ± 1.6 km · h−1). Oxygen consumption was used to compute the metabolic cost of running and ratings of perceived exertion (RPE) were recorded for each run. Ground contact time and step frequency were used to estimate leg stiffness. Identifiable minimums and a curvilinear relationship between ground contact time and metabolic cost was found for all runners (r2 = 0.84). A similar relationship was observed between leg stiffness and metabolic cost (r2 = 0.83). Most (90%) runners self-selected a ground contact time and leg stiffness that produced metabolic costs within 5% of their mathematical optimal. The majority (n = 6) of self-selected ground contact times were shorter than mathematical optimals, whilst the majority (n = 7) of self-selected leg stiffness' were higher than mathematical optimals. Metabolic cost and RPE were moderately associated (rs = 0.358 p = 0.011), but controlling for condition (habitual/manipulated) weakened this relationship (rs = 0.302, p = 0.035). Both ground contact time and leg stiffness appear to be self-optimized characteristics, as trained runners were operating at or close to their mathematical optimal. The majority of runners favored a self-selected gait that may rely on elastic energy storage and release due to shorter ground contact times and higher leg stiffness's than optimal. Using RPE as a surrogate measure of metabolic cost during manipulated running gait is not recommended.en_US
dc.language.isoenen_US
dc.publisherFrontiers Mediaen_US
dc.relation.ispartofseriesFrontiers in Sports and Active Living;
dc.subjectself-optimizationen_US
dc.subjectoxygen consumptionen_US
dc.subjectrunning mechanicsen_US
dc.subjectrunning economyen_US
dc.subjectperceived efforten_US
dc.titleHumans Optimize Ground Contact Time and Leg Stiffness to Minimize the Metabolic Cost of Runningen_US
dc.typeArticleen_US
dc.identifier.doihttps://doi.org/10.3389/fspor.2019.00053
dcterms.dateAccepted2019-10-14
rioxxterms.funderCardiff Metropolitan Universityen_US
rioxxterms.identifier.projectCardiff Metropolian (Internal)en_US
rioxxterms.versionVoRen_US
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en_US
rioxxterms.licenseref.startdate2019-11-08
rioxxterms.funder.project37baf166-7129-4cd4-b6a1-507454d1372een_US


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