Engstrom Craig M, Walker Duncan G, Kippers Vaughan, Mehnert Andrew J H
School of Human Movement Studies, The University of Queensland, and Department of Radiology, The Royal Brisbane Hospital, Brisbane, Australia.
Med Sci Sports Exerc. 2007 Jun;39(6):910-7. doi: 10.1249/mss.0b013e3180408e25.
This prospective study examined the association between quadratus lumborum (QL) asymmetry and the development of symptomatic pars interarticularis lesions in the lumbar spine of adolescent cricket fast bowlers.
Annual magnetic resonance imaging was used to measure QL volume asymmetry and for identifying pars lesions of the lumbar vertebrae in fast bowlers (N=51) and a control group of swimmers (N=18). Manual segmentation of axial images spanning the lumbar spine was performed to calculate percent QL asymmetry relative to the bowling- or throwing- (swimmers) arm side. Asymmetry above 100% indicated a larger QL volume on the bowling- (throwing) arm side.
The mean QL asymmetry in bowlers of 110.5% (SD=12.1%) was significantly different from the 96.6% (SD=5.0%) asymmetry in swimmers (t=6.75, P<or=0.001). In bowlers with symptomatic unilateral L4 pars lesions (N=11), which all developed opposite the bowling-arm side, the mean 124.3% (SD=8.3%) QL asymmetry exceeded the 106.7% (SD=10.1%) asymmetry in bowlers without these one-sided lesions. A logistic regression model (intercept=-22.1, P<or=0.001; asymmetry coefficient=0.18, P<or=0.001) demonstrated a significant association between increasing QL asymmetry and L4 lesions in bowlers. Receiver operating characteristic curve analysis demonstrated that QL asymmetry was an excellent predictor of L4 lesions in fast bowlers (area under curve=0.89, 95% confidence interval: 0.79, 0.98).
The strong association between QL asymmetry and the development of symptomatic unilateral L4 pars lesions in adolescent bowlers conceivably reflects a mechanical coupling between the loading milieu generating these injuries and preferential hypertrophy of this paraspinal muscle in response to repetitive activation during fast bowling.
本前瞻性研究探讨了青少年板球快速投球手腰椎腰方肌（QL）不对称与症状性关节突间部病变发生之间的关联。
每年使用磁共振成像测量快速投球手（N = 51）和游泳运动员对照组（N = 18）的QL体积不对称性，并识别腰椎的关节突间部病变。对跨越腰椎的轴向图像进行手动分割，以计算相对于投球或投掷（游泳运动员）手臂侧的QL不对称百分比。不对称超过100%表明投球（投掷）手臂侧的QL体积更大。
投球手中QL的平均不对称性为110.5%（标准差 = 12.1%），与游泳运动员中96.6%（标准差 = 5.0%）的不对称性有显著差异（t = 6.75，P≤0.001）。在有症状性单侧L4关节突间部病变的投球手（N = 11）中，所有病变均发生在与投球手臂相对的一侧，其平均QL不对称性为124.3%（标准差 = 8.3%），超过了没有这些单侧病变的投球手中106.7%（标准差 = 10.1%）的不对称性。逻辑回归模型（截距 = -22.1，P≤0.001；不对称系数 = 0.18，P≤0.001）表明，投球手中QL不对称性增加与L4病变之间存在显著关联。受试者工作特征曲线分析表明，QL不对称性是快速投球手中L4病变的优秀预测指标（曲线下面积 = 0.89，95%置信区间：0.79，0.98）。
青少年投球手中QL不对称与症状性单侧L4关节突间部病变的发生之间的强关联可能反映了产生这些损伤的负荷环境与该椎旁肌在快速投球过程中因反复激活而出现的优先肥大之间的机械耦合。
