两种不同姿势模拟着陆足底生物力学特点

Height dependent kinematics of the foot in response to variant landing positions

目的对半蹲式并腿和分腿式2种着陆姿势足底动力学特征进行评估。方法健康男性伞兵受试者20例。使用一个Pedar足底压力系统。检测足底最大应力值(地面反作用力)、足底最大压力值、足底最大压力时间积分值。足底根据解剖特点划分为10个区域。受试者从高60 cm台上跳下,分别以半蹲式并腿和分腿式姿势着地,记录足底动力学指标值,并进行分析、比较。结果 2种姿势之间比较足底最大应力值、最大压力值差异无统计学意义,而足底最大压力时间积分值在右足底有明显差异;同一种姿势着地左、右足底动力学指标值差异无统计学意义。但在左、右足不同时着地的概率方面分腿式着地明显高于半蹲式并腿着地。结论半蹲式并腿着陆姿势更适合军事跳伞等职业运动。

Objective We intended to evaluate the effectiveness of landing in either the half-squat-type position, common in military occupational specialties including parachute jumping, or the straddle-type position, common in athletic sports such as gymnastics.In landing from jumps at a height, asynchronous landing on either the right or left foot may increase impact forces, potentially resulting in injury. Methods In order to provide a kinematic assessment of the most effective landing position, a group of 20 health male subjects with current Chinese Army PLA paratrooper training were enrolled. Using a Pedar ＋ Pliance （a brand, containing system pressure receptors） in-shoe pressure monitoring system individually fitted for each subject by in-sole size, the ground reaction forces （GRFs）, landing pressures （LPs）, and pressure time intervals （PTIs） affecting 10 distinct regions of the foot upon jumping from a height of 60 cm and landing in either the half-squat-type or straddle-type landing position were assessed. Results No significant differences were observed between the two landing positions except for a notable variation in PTI resulting in increasing asynchronous landing when the straddle-type landing position was employed.Conclusion These findings suggest that, with proper training, the half-squat-type landing position may reduce the probability of asynchronous landing on either the left or right foot when jumping from a height of 60 cm. Thus, the half-squat-type landing position is superior to the straddle-type landing position kinematically, which confirms the practical use of this landing style in occupational activities, such as military parachute jumping.