title: The effect of lumbar posture on abdominal muscle thickness during an isometric leg task in people with and without non-specific low back pain.
abstract: This study investigated the effect of lumbar posture on function of transversus abdominis (TrA) and obliquus internus (OI) in people with and without non-specific low back pain (LBP) during a lower limb task. Rehabilitative ultrasound was used to measure thickness change of TrA and OI during a lower limb task that challenged the stability of the spine. Measures were taken in supine in neutral and flexed lumbar postures in 30 patients and 30 healthy subjects. Data were analysed using a two-way (groups, postures) ANOVA. Our results showed that lumbar posture influenced percent thickness change of the TRA muscle but not for OI. An interaction between group and posture was found for TrA thickness change (F(1,56) = 6.818, p = 0.012). For this muscle, only healthy participants showed greater thickness change with neutral posture compared to flexed (mean difference = 6.2%; 95% CI: 3.1-9.3%; p < 0.001). Comparisons between groups for both muscles were not significant. Neutral lumbar posture can facilitate an increase in thickness of the TrA muscle while performing a leg task, however this effect was not observed for this muscle in patients with LBP. No significant difference in TrA and OI thickness change between people with and without non-specific LBP was found.
authors.affiliation: Departamento de Fisioterapia, Universidade Federal de Minas Gerais, MG, Brazil. rafaelzambelli@gmail.com
authors.forename: Rafael Zambelli
authors.initials: RZ
authors.lastname: Pinto
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: Ferreira
authors.forename: Marcia Rodrigues
authors.initials: MR
authors.lastname: Franco
authors.forename: Mariana Calais
authors.initials: MC
authors.lastname: Ferreira
authors.forename: Manuela Loureiro
authors.initials: ML
authors.lastname: Ferreira
authors.forename: Luci Fuscaldi
authors.initials: LF
authors.lastname: Teixeira-Salmela
authors.forename: Vinicius C
authors.initials: VC
authors.lastname: Oliveira
authors.forename: Christopher
authors.initials: C
authors.lastname: Maher
mesh_terms: D000009:Abdominal Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D016001:Confidence Intervals; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011187:Posture / Q000502:physiology*; D012016:Reference Values; D012720:Severity of Illness Index; D014463:Ultrasonography