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dc.contributor.authorArmstrong, Craig
dc.contributor.authorSamuel, Jake
dc.contributor.authorYarlett, Andrew
dc.contributor.authorCooper, Stephen-Mark
dc.contributor.authorStembridge, Mike
dc.contributor.authorStöhr, Eric J.
dc.identifier.citationArmstrong, C., Samuel, J., Yarlett, A., Cooper, S-M, Stembridge, M., Stöhr, E.J. (2016) 'The effects of exercise intensity vs. metabolic state on the variability and magnitude of left ventricular twist mechanics during exercise', PLoS ONE 11(4): e0154065. doi:10.1371/journal.pone.0154065en_US
dc.descriptionThis article was published open access in PLoS ONE on 21 April 2016 (online), available at
dc.description.abstractIncreased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32–69% of O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results.en_US
dc.publisherPublic Library of Scienceen_US
dc.relation.ispartofseriesPLoS ONE;
dc.rightsCreative Commons Attribution License
dc.subjectLV mechanicsen_US
dc.titleThe effects of exercise intensity vs. metabolic state on the variability and magnitude of left ventricular twist mechanics during exerciseen_US
rioxxterms.funderCardiff Metropolitan University
rioxxterms.identifier.projectCardiff Metropolian (Internal)

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