Affiliations: School of Health Sciences, University of South
Australia, Adelaide, Australia | School of Mechanical Engineering, The University of
Adelaide, Adelaide, Australia | School of Medical Sciences, The University of
Adelaide, Adelaide, Australia | International Centre for Allied Health Evidence,
Division of Health Sciences, University of South Australia, Adelaide,
Australia | Centre for Regional Engagement, University of South
Australia, Adelaide, Australia
Note: [] Address for correspondence: Paul Grimshaw, School of Mechanical
Engineering, The University of Adelaide, Adelaide, Australia, SA 5005, USA.
Tel.: +61 8 8313 4805; Fax: +61 8 8313 4367; E-mail: paul.grimshaw@adelaide.edu.au
Abstract: BACKGROUND: It is well accepted that both multifidus and transversus
abdominis muscles have a vital role in maintaining spinal stability. OBJECTIVE: To determine if multifidus and transversus abdominis could be
strengthened by a six-week conditioning program and to establish if the amount
of electromyographic (EMG) activity in external oblique differed in a lifting
and holding task after the conditioning program. METHODS: EMG activity of
external oblique during a lifting and holding task was obtained. Multifidus
cross-sectional area and transversus abdominis width were measured using real
time ultrasound in six males and five females, with no back pain (mean age of
26.3 (± 5.4) years). The participants then performed a six-week
muscle-conditioning program for multifidus and transversus abdominis, after
which the EMG activity of external oblique and dimensions of multifidus and
transversus abdominis were re-measured. RESULTS: Both multifidus and
transversus abdominis significantly increased in size. There was significantly
less activity in external oblique during a lifting task after the conditioning
program, with no change in external oblique activity during a holding task. CONCLUSIONS: this study may indicate a link between the dimensional
increase of multifidus and transversus abdominis, and the decrease in EMG
activity in external oblique during lifting.
Keywords: Lifting, muscle conditioning and strengthening, EMG, real time ultrasound, spinal stability
