Factors Associated With Paraspinal Muscle Asymmetry in Size and Composition in a General Population Sample of Men

Maryse Fortin, Yan Yuan, Michele C. Battié

Discussion Podcast: Factors Associated With Paraspinal Muscle Asymmetry: A Study of Male Twins

Participants: Maryse Fortin, BSc, PhD, CAT(C), McGill University Health Center, Montreal, Quebec, Canada; Michele Battié, BSc, MSC, PhD, Professor and Canada Research Chair, Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada; Mark Bishop, PT, PhD, Associate Professor, Department of Physical Therapy and Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida; and Steven George, PT, PhD, Associate Professor and Assistant Department Chair, Department of Physical Therapy, Brooks Center for Rehabilitation Studies, University of Florida, and Editorial Board member, PTJ. Moderator: Leonardo Costa, PT, PhD, Associate Professor, Master's and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo, São Paulo, Brazil, and Editorial Board member, PTJ.

Files in this Data Supplement:

  • Discussion Podcast - Asymmetry of the paraspinal muscles recently has been associated with low back pain. As reported in the November 2013 issue of PTJ, University of Alberta researchers recruited more than 200 adult male twins to look for factors associated with paraspinal muscle asymmetry. According to their study results, it appears that this asymmetry is a clinical finding with little or no significance. In this podcast, 2 of the authors, Maryse Fortin and Michele Battié, are joined by content experts Mark Bishop and Steven George and moderator Leonardo Costa to discuss these surprising findings. Where does research go from here? The group also discusses the use of a twin cohort—which is not common in the physical therapy literature—and the role of genetics in pain.

    Running time 22:53 (32.1 MB).

    Discussion Podcast:
    Factors Associated With Paraspinal Muscle Asymmetry:
    A Study of Male Twins

    Download the mp3 | Length: 22:53

    Quick Grabs

    Fortin: "I wanted to look at other factors besides low back pain and really see what else is there that can influence this asymmetry."

    Bishop: "We may need to acknowledge that the asymmetries are there but not focus on those as primary targets."

    George: "I think the appeal of the subgrouping is that it's immediately clinically applicable, and I think that's what keeps a lot of people interested in it."

    Battié: "Julie Hides had mentioned that…an asymmetry of 10% could be looked upon as an important difference clinically; I think that now we could say probably not."


    Fortin M, Macedo LG. Multifidus and paraspinal muscle group cross-sectional areas of patients with low back pain and controls: a systematic review with a focus on blinding. Phys Ther. 2013;93:873–888.

    George S, Parr J, Wallace M, et al. Genetic and psychological risk factors are associated with pain and disability in an experimentally induced acute shoulder pain model. J Pain. 2012;13(4 suppl):S29.

    Parr J, Fillingim R, Wallace M, et al. Genetic risk factors are associated with physical impairment in an experimentally induced acute shoulder pain model. J Pain. 2012;13(4 suppl):S101.

    Hides J, Gilmore C, Stanton W, Bohlscheid E. Multifidus size and symmetry among chronic LBP and healthy asymptomatic subjects. Man Ther. 2008;13:43-49.

    Bystr?m MG, Rasmussen-Barr E, Grooten WJ. Motor control exercises reduces pain and disability in chronic and recurrent low back pain: a meta-analysis. Spine. 2013;38:E350-358.

    Teyhen DS, Childs JD, Dugan JL, et al. Effect of two different exercise regimens on trunk muscle morphometry and endurance in soldiers in training. Phys Ther. 2013;93:1211-1224.

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