Measurement of lumbar multifidus asymmetry in amateur cricket pace bowlers using real-time ultrasound

Objectives: To determine if lumbar multifidus asymmetry existed between the fifth lumbar (L5) and 1stsacral (S1) spinal level in a group of amateur cricket pace bowlers and a healthy non-cricketing group of males, and to determine if there were significant differences between groups in lumbar multifidus asymmetry at rest, on contraction, or during activation. Design: A prospective single blinded cross-sectional study. Methods: Forty healthy participants were recruited to two groups: an amateur cricket pace bowling group (n=20) and a non-cricketing group (n=20). Bilateral real-time ultrasound imaging of lumbar multifidus was conducted at the L5/S1 level in a resting and contracted state. Muscle thickness was measured and percentage activation was calculated. A force probe device was used to standardise force, inclination and roll of the ultrasound probe during real-time ultrasound imaging. Results: There was evidence of asymmetry in both groups, but differences between dominant and non-dominant sided lumbar multifidus thickness were non-significant. Between group comparisons of lumbar multifidus asymmetry indicated no significant difference for rest or activation. However, the cricket group had a significantly greater asymmetry of lumbar multifidus when contracted compared to controls (p=0.04). Conclusions: The results indicate that amateur cricket pace bowlers had significantly greater contracted lumbar multifidus asymmetry than non-cricketers. The resting lumbar multifidus asymmetries demonstrated previously in elite pace bowlers were not found in this population. Future research should investigate lumbar multifidus asymmetry in amateur pace bowlers in relation to lower back injury, and make comparisons between amateur and elite cricket pace bowlers