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dc.contributor.authorHides, Julie A
dc.contributor.authorLambrecht, Gunda
dc.contributor.authorSexton, Christopher T
dc.contributor.authorPruett, Casey
dc.contributor.authorPetersen, Nora
dc.contributor.authorJaekel, Patrick
dc.contributor.authorRosenberger, André
dc.contributor.authorWeerts, Guillaume
dc.date.accessioned2020-09-29T00:01:22Z
dc.date.available2020-09-29T00:01:22Z
dc.date.issued2020
dc.identifier.issn1529-9430
dc.identifier.doi10.1016/j.spinee.2020.09.006
dc.identifier.urihttp://hdl.handle.net/10072/397993
dc.description.abstractBACKGROUND CONTEXT: One of the primary changes in the neuromuscular system in response to microgravity is skeletal muscle atrophy, which occurs especially in muscles that maintain posture while being upright on Earth. Reduced size of paraspinal and abdominal muscles has been documented after spaceflight. Exercises are undertaken on the International Space Station (ISS) during and following space flight to remediate these effects. Understanding the adaptations which occur in trunk muscles in response to microgravity could inform the development of specific countermeasures, which may have applications for people with conditions on Earth such as low back pain (LBP). PURPOSE: The aim of this study was to examine the changes in muscle size and function of the lumbar multifidus (MF) and anterolateral abdominal muscles a) in response to exposure to 6- months of microgravity on the International Space Station and b) in response to a 15-day reconditioning program on Earth. DESIGN: Prospective longitudinal series PATIENT SAMPLE: Data were collected from 5 astronauts who undertook 7 long-duration missions on the ISS. OUTCOME MEASURES: For the MF muscle, measures included cross-sectional area (CSA) and linear measures to assess voluntary isometric contractions at vertebral levels L2 to L5. For the abdominal muscles, the thickness of the transversus abdominis (TrA), obliquus internus abdominis (IO) and obliquus externus abdominis (EO) muscles at rest and on contraction were measured. METHODS: Ultrasound imaging of trunk muscles was conducted at 4 timepoints (pre-flight, post-flight, mid-reconditioning, and post reconditioning). Data were analysed using multi-level linear models to estimate the change in muscle parameters of interest across three time periods. RESULTS: Beta-coefficients (estimates of the expected change in the measure across the specified time period, adjusted for the baseline measurement) indicated that the CSA of the MF muscles decreased significantly at all lumbar vertebral levels (except L2) in response to exposure to microgravity (L3= 12.6%; L4 = 6.1%, L5=10.3%; P<0.001), and CSAs at L3-L5 vertebral levels increased in the reconditioning period (P<0.001). The thickness of the TrA decreased by 34.1% (P<0.017), IO decreased by 15.4% (P=0.04) and the combination of anterolateral abdominal muscles decreased by 16.2% (P<0.001) between pre- and post-flight assessment and increased (TrA<0.008; combined P= 0.035) during the post-reconditioning period. Results showed decreased contraction of the MF muscles at the L2 (from 12.8% to 3.4%; P=0.007) and L3 (from 12.2% to 5%; P=0.032) vertebral levels following exposure to microgravity which increased (L2, P=0.046) after the post-reconditioning period. Comparison with pre-flight measures indicated that there were no residual changes in muscle size and function after the post-reconditioning period, apart from CSA of MF at L2, which remained 15.3% larger than pre-flight values (P<0.001). CONCLUSIONS: In-flight exercise countermeasures mitigated, but did not completely prevent, changes in the size and function of the lumbar MF and anterolateral abdominal muscles. Many of the observed changes in size and control of the MF and abdominal muscles that occurred in response to prolonged exposure to microgravity paralleled those seen in people with LBP or exposed to prolonged bedrest on Earth. Daily individualised post-flight reconditioning, which included both motor control training and weight-bearing exercises with an emphasis on retraining strength and endurance to re-establish normal postural alignment with respect to gravity, restored the decreased size and control of the MF (at the L3-L5 vertebral levels) and anterolateral abdominal muscles. Drawing parallels between changes which occur to the neuromuscular system in microgravity and which exercises best recover muscle size and function could help health professionals tailor improved interventions for terrestrial populations. Results suggested that the principles underpinning the exercises developed for astronauts following prolonged exposure to microgravity (emphasizing strength and endurance training to re-establish normal postural alignment and distribution of load with respect to gravity) can also be applied for people with chronic LBP, as the MF and anterolateral abdominal muscles were affected in similar ways in both populations. The results may also inform the development of new astronaut countermeasures targeting the MF and abdominal muscles.
dc.description.peerreviewedYes
dc.languageEnglish
dc.language.isoeng
dc.publisherElsevier
dc.relation.ispartofjournalThe Spine Journal
dc.subject.fieldofresearchClinical sciences
dc.subject.fieldofresearchNeurosciences
dc.subject.fieldofresearchcode3202
dc.subject.fieldofresearchcode3209
dc.subject.keywordsexercise therapy
dc.subject.keywordslumbar spine
dc.subject.keywordsparaspinal muscles
dc.subject.keywordsrehabilitation
dc.subject.keywordsspaceflight
dc.titleThe Effects of Exposure to Microgravity and Reconditioning of the Lumbar Multifidus and Anterolateral Abdominal muscles; Implications for people with LBP.
dc.typeJournal article
dc.type.descriptionC1 - Articles
dcterms.bibliographicCitationHides, JA; Lambrecht, G; Sexton, CT; Pruett, C; Petersen, N; Jaekel, P; Rosenberger, A; Weerts, G, The Effects of Exposure to Microgravity and Reconditioning of the Lumbar Multifidus and Anterolateral Abdominal muscles; Implications for people with LBP., The Spine Journal, 2020
dcterms.dateAccepted2020-09-16
dcterms.licensehttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.date.updated2020-09-28T02:02:56Z
dc.description.versionAccepted Manuscript (AM)
gro.description.notepublicThis publication has been entered in Griffith Research Online as an advanced online version.
gro.rights.copyright© 2020 Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (http://creativecommons.org/licenses/by-nc-nd/4.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, providing that the work is properly cited.
gro.hasfulltextFull Text
gro.griffith.authorHides, Julie A.


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