Girard Olivier, Brocherie Franck, Morin Jean-Benoit, Millet Grégoire P
Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; ISSUL, Institute of Sport Sciences, University of Lausanne, Switzerland.
ISSUL, Institute of Sport Sciences, University of Lausanne, Switzerland; Laboratory Sport, Expertise and Performance (EA 7370), Research Department, French Institute of Sport (INSEP), Paris, France.
Hum Mov Sci. 2017 Apr;52:203-214. doi: 10.1016/j.humov.2017.02.008. Epub 2017 Mar 1.
Stride mechanical imbalances between the lower limbs may be detrimental to performance and/or increase injury risks. This study describes the time course and magnitude of asymmetries in running mechanical variables during repeated treadmill sprints and examines whether inter-limb differences in sprinting mechanics increase with fatigue. Thirteen non-injured male athletes performed five 5-s sprints with 25-s recovery on an instrumented treadmill, allowing the continuous (step-by-step) measurement of running kinetics/kinematics and spring-mass characteristics calculation. For each variable, bilateral leg asymmetry (BLA%) between the left and the right leg was defined as: {[(high value-low value)/low value]×100}. BLA% for propulsive power and horizontal forces averaged ∼12-13%, while lower values occurred for step-averaged values of running velocity, resultant and vertical forces (all ∼4%). For all sprints, kinematic BLA% ranged from 1.6±1.0% (swing time) to 9.0±5.3% (aerial time). BLA% for vertical and leg stiffness was 6.4±4.9% and 7.6±3.6%, respectively. While distance covered decreased across repetitions (P<0.05), there was no significant interaction between sprint repetitions and leg side for any of the mechanical variables studied (all P>0.05). Although inter-limb differences were observed for many running kinetics/kinematics and spring-mass characteristics during repeated treadmill sprints, the lack of interaction between sprint repetitions and leg side suggests that lower limbs fatigued at a similar rate.
下肢之间的步幅机械不平衡可能对运动表现有害和/或增加受伤风险。本研究描述了重复跑步机冲刺过程中跑步机械变量不对称的时间进程和幅度，并研究了冲刺力学中的肢体间差异是否会随着疲劳而增加。13名未受伤的男性运动员在一台装有仪器的跑步机上进行了5次5秒的冲刺，每次冲刺后有25秒的恢复时间，从而能够连续（逐步骤）测量跑步动力学/运动学并计算弹簧质量特征。对于每个变量，左右腿之间的双侧腿部不对称（BLA%）定义为：{[(高值 - 低值)/低值]×100}。推进力和水平力的BLA%平均约为12 - 13%，而跑步速度、合力和垂直力的步平均值的BLA%较低（均约为4%）。对于所有冲刺，运动学BLA%范围从1.6±1.0%（摆动时间）到9.0±5.3%（腾空时间）。垂直刚度和腿部刚度的BLA%分别为6.4±4.9%和7.6±3.6%。虽然重复冲刺过程中覆盖的距离减少（P<0.05），但对于所研究的任何机械变量，冲刺重复次数和腿侧之间均无显著交互作用（所有P>0.05）。尽管在重复跑步机冲刺过程中观察到许多跑步动力学/运动学和弹簧质量特征存在肢体间差异，但冲刺重复次数和腿侧之间缺乏交互作用表明下肢以相似的速率疲劳。
