Transversus abdominis and multifidus asymmetry in runners measured by MRI: a cross-sectional study Mitchell, Ulrike H, Johnson, A Wayne, Owen, Patrick J, Rantalainen, Timo and Belavy, Daniel 2019, Transversus abdominis and multifidus asymmetry in runners measured by MRI: a cross-sectional study, BMJ open sport and exercise medicine, vol. 5, pp. 1-8, doi: 10.1136/bmjsem-2019-000556. Attached Files Name Description MIMEType Size Downloads Title Transversus abdominis and multifidus asymmetry in runners measured by MRI: a cross-sectional study Author(s) Mitchell, Ulrike H Johnson, A Wayne Owen, Patrick J orcid.org/0000-0003-3924-9375 Rantalainen, Timo orcid.org/0000-0001-6977-4782 Belavy, Daniel orcid.org/0000-0002-9307-832X Journal name BMJ open sport and exercise medicine Volume number 5 Article ID e000556 Start page 1 End page 8 Total pages 8 Publisher BMJ Place of publication London, Eng. Publication date 2019-09 ISSN 2055-7647 Keyword(s) Activation Core Muscle Rehabilitation Running Summary Objective The transversus abdominis muscle (TrA) is active during running as a secondary respiratory muscle and acts, together with the multifidus, as trunk stabiliser. The purpose of this study was to determine size and symmetry of TrA and multifidus muscles at rest and with contraction in endurance runners without low back pain. Design Cross-sectional study. Setting A medical imaging centre in Melbourne, Australia. Participants Thirty middle-aged (43years±7) endurance-trained male (n=18) and female (n=12) runners without current or history of low back pain. Outcome measures MRI at rest and with the core engaged. The TrA and multifidus muscles were measured for thickness and length (TrA) and anteroposterior and mediolateral thickness (multifidus). Muscle activation was extrapolated from rest to contraction and compared with the same and contralateral side. Paired t-tests were performed to compare sides and contraction status. Results Left and right TrA and multifidus demonstrated similar parameters at rest (p>0.05). However, with contraction, the right TrA and multifidus (in mediolateral direction) were 9.2% (p=0.038) and 42% (p<0.001) thicker, respectively, than their counterparts on the left. There was no TrA thickness side difference with contraction in left-handed participants (p=0.985). When stratified by sex, the contracted TrA on the right side remained 8.4% thicker, but it was no longer statistically significant (p=0.134). The side difference with contraction of the TrA became less with increasing training age. Conclusions Right-handed long-term runners without low back pain exhibit a greater right side core muscle activation when performing an isometric contraction. This activation preference diminishes with increasing training age. Language eng DOI 10.1136/bmjsem-2019-000556 Indigenous content off HERDC Research category C1 Refereed article in a scholarly journal Copyright notice ©2019, Author(s) Persistent URL http://hdl.handle.net/10536/DRO/DU:30129721 Document type: Journal Article Collections: Faculty of Health School of Exercise and Nutrition Sciences Open Access Checking Related Links Link Description Connect to published version Go to link with your DU access privileges     Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved. Versions Version Filter Type Fri, 13 Sep 2019, 15:50:30 EST Sat, 14 Sep 2019, 05:00:18 EST Mon, 16 Sep 2019, 08:00:03 EST Tue, 01 Oct 2019, 06:05:02 EST Sat, 05 Oct 2019, 02:33:32 EST Fri, 11 Oct 2019, 15:03:10 EST Fri, 11 Oct 2019, 15:06:31 EST Filtered Full Citation counts:   Cited 0 times in TR Web of Science Cited 0 times in Scopus Search Google Scholar Access Statistics: 11 Abstract Views, 1 File Downloads  -  Detailed Statistics Created: Fri, 13 Sep 2019, 15:50:30 EST

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