Size and Symmetry of Trunk Muscles in Ballet Dancers With and Without Low Back Pain

Gildea, Jan E., Hides, Julie A. and Hodges, Paul W. (2013) Size and Symmetry of Trunk Muscles in Ballet Dancers With and Without Low Back Pain. Journal of Orthopaedic & Sports Physical Therapy, 43 8: 525-533. doi:10.2519/jospt.2013.4523

Author Gildea, Jan E.
Hides, Julie A.
Hodges, Paul W.
Title Size and Symmetry of Trunk Muscles in Ballet Dancers With and Without Low Back Pain
Journal name Journal of Orthopaedic & Sports Physical Therapy   Check publisher's open access policy
ISSN 0190-6011
Publication date 2013-08-01
Year available 2013
Sub-type Article (original research)
DOI 10.2519/jospt.2013.4523
Open Access Status DOI
Volume 43
Issue 8
Start page 525
End page 533
Total pages 9
Place of publication Alexandria, United States
Publisher American Physical Therapy Association * Orthopedic Section
Language eng
Abstract This study evaluated lumbar spine muscle volume and Muscle Fatty Infiltrate (MFI) across two age groups of healthy adults. Twenty-four participants (young group - YG: age 18-25, n = 12; mature group - MG: age 45-60, n = 12) without low back pain underwent T1-weighted axial MRI. Muscle volume and MFI were obtained from the left and right lumbar erector spinae (ES), multifidus (M), rectus abdominis (RA) and psoas (PS) muscles. For MFI, mean pixel intensity (MPI) of muscles was reported as a percentage of subcutaneous fat MPI. Within-group comparison of left and right side muscle volume was not significantly different in the YG. In the MG, right RA and ES were significantly smaller than left (RA p = 0.049; ES p = 0.03). In both groups, left PS, M and ES MFI was significantly smaller compared to the right side and left RA MFI was significantly greater compared to right side (all p ≤ 0.001). For M volume, 81.7-84.6% of variance was explained by age, height and Body Mass Index (BMI). For ES volume, 81.6-82.8% of variance was explained by height and BMI. Age explained 18.1%-36.0% of variance in M and ES right MFI. Therefore, age and BMI are relevant factors for extensor muscle volume, but not for flexor muscle volume. Also, age significantly influences MFI for right-sided extensors only. The age effect is apparently independent of full subjective back functionality. For future spinal muscle research, the side-and muscle-specific effect of age on muscle morphology should be considered.
Formatted abstract
Study Design Cross-sectional, observational study.

Objectives To investigate the cross-sectional area (CSA) of trunk muscles in professional ballet dancers with and without low back pain (LBP).

Background LBP is the most prevalent chronic injury in classical ballet dancers. Research on nondancers has found changes in trunk muscle size and symmetry to be associated with LBP. There are no studies that examine these changes in ballet dancers.

Methods Magnetic resonance imaging was performed in 14 male and 17 female dancers. The CSAs of 4 muscles (multifidus, lumbar erector spinae, psoas, and quadratus lumborum) were measured and compared among 3 groups of dancers: those without LBP or hip pain (n = 8), those with LBP only (n = 13), and those with both hip-region pain and LBP (n = 10).

Results Dancers with no pain had larger multifidus muscles compared to those with LBP at L3–5 (P<.024) and those with both hip-region pain and LBP at L3 and L4 on the right side (P<.027). Multifidus CSA was larger on the left side at L4 and L5 in dancers with hip-region pain and LBP compared to those with LBP only (P<.033). Changes in CSA were not related to the side of pain (all, P>.05). The CSAs of the other muscles did not differ between groups. The psoas (P<.0001) and quadratus lumborum (P<.01) muscles were larger in male dancers compared to female dancers. There was a positive correlation between the size of the psoas muscles and the number of years of professional dancing (P = .03).

Conclusion In classical ballet dancers, LBP and hip-region pain and LBP are associated with a smaller CSA of the multifidus but not the erector spinae, psoas, or quadratus lumborum muscles.
Keyword dance
muscle cross-sectional area
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID P 24020
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
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