Institute for Sport and Sport Science, University of Freiburg, Freiburg, Germany.
J Sports Sci Med. 2021 Oct 1;20(4):743-750. doi: 10.52082/jssm.2021.743. eCollection 2021 Dec.
Trunk motion is most likely to influence knee joint injury risk, but little is known about sex-related differences in trunk neuromuscular control during changes of direction. The purpose of the present study was to test whether differences in trunk control between males and females during changes of direction exist. Twelve female and 12 male recreational athletes (with at least 10 years of experience in team sport) performed unanticipated changes of direction with 30° and 60° cut angles, while 3D trunk and leg kinematics, ground reaction forces and trunk muscles electromyography were recorded. Trunk kinematics at the time of peak knee abduction moment and directed co-contraction ratios for trunk muscles during the pre-activation and weight acceptance phases were determined. None of the trunk kinematics and co-contraction ratio variables, nor peak knee abduction moment differed between sexes. Compared to the 30° cut, trunk lateral flexion remained unchanged and trunk external rotation was reduced (p < 0.001; η² (partial eta squared for effect size) = 0.78), while peak knee abduction moment was increased (p < 0.001; η² = 0.84) at 60°. The sharper cutting angle induced muscle co-contraction during the pre-activation directed less towards trunk flexors (p < 0.01; η² = 0.27) but more towards trunk medial flexors and rotators opposite to the movement direction (p < 0.001; η² > 0.46). However, muscle co-contraction during the weight acceptance phase remained comparable between 30° and 60°. The lack of sex-related differences in trunk control does not explain knee joint injury risk discrepancies between sexes during changes of direction. Trunk neuromuscular strategies during sharper cutting angles revealed the importance of external oblique muscles to maintain trunk lateral flexion at the expense of trunk rotation. This provides new information for trunk strength training purposes for athletes performing changes of direction.
躯干运动最有可能影响膝关节受伤的风险，但对于在改变方向时躯干神经肌肉控制的性别差异知之甚少。本研究的目的是测试在改变方向时男性和女性之间的躯干控制是否存在差异。12 名女性和 12 名男性休闲运动员（至少有 10 年团队运动经验）进行了 30°和 60°切入角的非预期改变方向，同时记录了 3D 躯干和腿部运动学、地面反作用力和躯干肌肉肌电图。确定了在膝关节外展力矩峰值时的躯干运动学和在预激活和承重阶段时躯干肌肉的共同收缩比。性别之间没有任何躯干运动学和共同收缩比变量，也没有峰值膝关节外展力矩不同。与 30°切口相比，躯干横向屈曲保持不变，躯干外旋减少（p<0.001；η²（偏η平方用于效应大小）=0.78），而在 60°时峰值膝关节外展力矩增加（p<0.001；η²=0.84）。更陡峭的切割角度在预激活期间引起的肌肉共同收缩更偏向于躯干屈肌（p<0.01；η²=0.27），但更偏向于与运动方向相反的躯干内侧屈肌和旋转肌（p<0.001；η²>0.46）。然而，在承重阶段的肌肉共同收缩在 30°和 60°之间保持相当。在改变方向时，性别之间躯干控制没有差异，这并不能解释膝关节受伤风险的性别差异。在更陡峭的切割角度下，躯干神经肌肉策略显示了外斜肌的重要性，以牺牲躯干旋转为代价来维持躯干横向屈曲。这为进行改变方向的运动员提供了躯干力量训练的新信息。
