Purpose: This study aimed to analyze lumbo-pelvic lateral flexion kinematics and kinetics in junior fast bowlers and compare bowlers with varying quadratus lumborum (QL) cross-sectional area (CSA) asymmetry profiles.
Methods: Magnetic resonance imaging was used to determine QL CSA of 39 participants who also underwent three-dimensional analysis of their bowling action.
Results: Bowlers with greater than 10% QL asymmetry (n = 26) experienced a larger peak lumbo-pelvic lateral flexion; angle (21.6° ± 4.2°), angular velocity (314.9°·s−1 ± 86.6°·s−1), moment (12.8 ± 2.5 N·m·kg−1·m−1), positive power (25.6 ± 12.6 W·kg−1·m−1), and negative power (48.6 ± 20.9 W·kg−1·m−1) compared with the bowlers with less than 10% asymmetry (n = 13) (angle = 18.1° ± 1.9°, angular velocity = 243.8°·s−1 ± 64.9°·s−1, moment = 10.4 ± 2.8 N·m·kg−1·m−1, positive power = 14.7 ± 7.4 W·kg−1·m−1, and negative power = 33.8 ± 17.7 W·kg−1·m−1; P < 0.05).
Conclusion: Fast bowlers with QL CSA asymmetry in excess of 10% experience increased lumbo-pelvic lateral flexion loads during bowling. As increased lateral flexion loads may increase the risk of spondylolysis development, the presence of large QL asymmetry may be a useful screening tool for identifying bowlers at risk of developing lumbar spondylolysis.