The role of quadratus lumborum asymmetry in the occurrence of lesions in the lumbar vertebrae of cricket fast bowlers

de Visser, Hans; Adam, Clayton J.; Crozier, Stuart; Pearcy, Mark J.

doi:10.1016/j.medengphy.2006.09.010

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Volume 29, Issue 8 , Pages 877-885, October 2007

The role of quadratus lumborum asymmetry in the occurrence of lesions in the lumbar vertebrae of cricket fast bowlers

Hans de Visser
- School of Engineering Systems & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- Corresponding author at: School of Engineering Systems & Institute of Health and Biomedical Innovation, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. Tel.: +61 7 3138 1377; fax: +61 7 3138 8381.
Clayton J. Adam
- School of Engineering Systems & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
Stuart Crozier
- School of Information Technology & Electrical Engineering, University of Queensland, Brisbane, Australia
Mark J. Pearcy
- School of Engineering Systems & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia

Received 3 March 2006; received in revised form 19 September 2006; accepted 19 September 2006. published online 08 November 2006.

Abstract

In cricket fast bowlers an increased incidence of stress fractures or lesions in the L4 pars interarticularis is observed, which shows a strong statistical correlation with the presence of hypertrophy in the contralateral Quadratus Lumborum (QL) muscle. This study aims to find a physical explanation for this correlation.

A mathematical model was used to estimate the forces and moments on the L3 and L4 vertebrae in six postures attained during fast bowling. These forces and moments were used in finite element models to estimate the stresses in the pars interarticularis. Two scenarios were examined per posture: symmetric QL muscles, and right QL muscle volume 30% enlarged. Influence of muscle activation was also investigated.

QL asymmetry only correlates with significant stress increases when stress levels are relatively low. When stress levels are high, due to extreme posture or muscle activation, asymmetry only causes small stress changes, suggesting that asymmetry is not the cause of stress fractures in the pars. There are even indications that asymmetry might help to reduce stresses, but more detailed knowledge of the size and activation of the lumbar muscles is needed to confirm this.

Keywords: Cricket fast bowlers, Pars interarticularis, Quadratus lumborum asymmetry, Fractures, Lumbar spine, Finite element modelling, Musculoskeletal modelling