School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UNITED KINGDOM.
Department of Science and Technology, Nottingham Trent University, Nottingham, UNITED KINGDOM.
Med Sci Sports Exerc. 2022 Mar 1;54(3):438-446. doi: 10.1249/MSS.0000000000002820.
Localized bone mineral density (BMD) adaptation of the lumbar spine, particularly on the contralateral side to the bowling arm, has been observed in elite male cricket fast bowlers. No study has investigated this in adolescents, or the role of fast bowling technique on lumbar BMD adaptation. This study aims to investigate lumbar BMD adaptation in adolescent cricket fast bowlers, and its relationship with fast bowling technique.
Thirty-nine adolescent fast bowlers underwent anteroposterior dual x-ray absorptiometry scan of their lumbar spine. Hip, lumbopelvic and thoracolumbar joint kinematics, and vertical ground reaction kinetics were determined using three-dimensional motion capture and force plates. Significant partial (covariate: fat-free mass) and bivariate correlations of the technique parameters with whole lumbar (L1-L4) BMD and BMD asymmetry (L3 and L4) were advanced as candidate variables for multiple stepwise linear regression.
Adolescent fast bowlers demonstrated high lumbar Z-Scores (+1.0; 95% confidence interval [CI], 0.7-1.4) and significantly greater BMD on the contralateral side of L3 (9.0%; 95% CI, 5.8%-12.1%) and L4 (8.2%; 95% CI, 4.9%-11.5%). Maximum contralateral thoracolumbar rotation and maximum ipsilateral lumbopelvic rotation in the period between back foot contact and ball release (BR), as well as contralateral pelvic drop at front foot contact, were identified as predictors of L1 to L4 BMD, explaining 65% of the variation. Maximum ipsilateral lumbopelvic rotation between back foot contact and BR, as well as ipsilateral lumbopelvic rotation and contralateral thoracolumbar side flexion at BR, were predictors of lumbar asymmetry within L3 and L4.
Thoracolumbar and lumbopelvic motion are implicated in the etiology of the unique lumbar bone adaptation observed in fast bowlers whereas vertical ground reaction force, independent of body mass, was not. This may further implicate the osteogenic potential of torsional rather than impact loading in exercise-induced adaptation.
在精英男性板球快速投球手中，已经观察到腰椎的局部骨密度（BMD）适应，特别是在投球臂的对侧。尚无研究调查过青少年或快速投球技术对腰椎 BMD 适应的影响。本研究旨在调查青少年板球快速投球手中的腰椎 BMD 适应情况，及其与快速投球技术的关系。
39 名青少年快速投球手接受了腰椎前后双 X 射线吸收法扫描。使用三维运动捕捉和测力板确定髋关节、腰骶关节和胸腰关节运动学以及垂直地面反作用力动力学。对技术参数与整个腰椎（L1-L4）BMD 和 BMD 不对称（L3 和 L4）的显著部分（协变量：去脂体重）和双变量相关性进行了先进分析，作为多元逐步线性回归的候选变量。
青少年快速投球手的腰椎 Z 评分较高（+1.0；95%置信区间[CI]，0.7-1.4），并且 L3（9.0%；95%CI，5.8%-12.1%）和 L4（8.2%；95%CI，4.9%-11.5%）的对侧侧骨密度明显更高。在从后脚接触到球释放（BR）期间，最大对侧胸腰椎旋转和最大同侧腰骶旋转，以及前脚接触时的对侧骨盆下降，被确定为 L1 至 L4 BMD 的预测因子，解释了 65%的变异。在从后脚接触到 BR 期间的最大同侧腰骶旋转，以及在 BR 期间的同侧腰骶旋转和对侧胸腰椎侧屈，是 L3 和 L4 内腰椎不对称的预测因子。
胸腰椎和腰骶关节运动与快速投球手中观察到的独特腰椎骨适应有关，而垂直地面反作用力与体重无关。这可能进一步暗示扭转负荷而不是冲击负荷在运动引起的适应中的成骨潜力。
