title: Effects of posture on the thickness of transversus abdominis in pain-free subjects.
abstract: The role of transversus abdominis (TrA) on spinal stability may be important in low back pain (LBP). To date, there have not been any investigations into the influence of lumbo-pelvic neutral posture on TrA activity. The present study therefore examines whether posture influences TrA thickness. A normative within-subjects single-group study was carried out. Twenty healthy adults were recruited and taught five postures: (1) supine lying; (2) erect sitting (lumbo-pelvic neutral); (3) slouched sitting; (4) erect standing (lumbo-pelvic neutral); (5) sway-back standing. In each position, TrA thickness was measured (as an indirect measure of muscle activity) using ultrasound. In erect standing, TrA (mean TrA thickness: 4.63+/-1.35 mm) was significantly thicker than in sway-back standing (mean TrA thickness: 3.32+/-0.95 mm) (p=00001). Similarly, in erect sitting TrA (mean thickness=4.30 mm+/-1.58 mm) was found to be significantly thicker than in slouched sitting (mean thickness=3.46 mm+/-1.13 mm) (p=0002). In conclusion, lumbo-pelvic neutral postures may have a positive influence on spinal stability compared to equivalent poor postures (slouched sitting and sway-back standing) through the recruitment of TrA. Therefore, posture may be important for rehabilitation in patients with LBP.
authors.affiliation: 19th Street Physiotherapy Clinic, Vancouver V7M1X5, Canada. amreeve@19physio.com
authors.forename: Angelica
authors.initials: A
authors.lastname: Reeve
authors.forename: Andrew
authors.initials: A
authors.lastname: Dilley
mesh_terms: D000009:Abdominal Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D015203:Reproducibility of Results; D014463:Ultrasonography