中国伞兵着陆时足底动力学指标的变化特征

Change of plantar dynamics in Chinese parachutists at landing

  • 摘要: 目的 观察伞兵着陆过程中左、右足底动力学指标变化规律。 方法 利用德国Pedar-X足底压力检测系统检测12名现役八一跳伞大队的跳伞运动员模拟伞兵从1.5米跳台跳下着陆时足底最大应力、最大压力、接触面积、压力时间积分值等动力学指标。将左、右足底按照常规标准分为10区,分别记录各区的动力学指标值,观察各区指标的变化规律,同时比较左、右足底相应各区的动力学指标值。 结果 左足底最大压力值(kPa)分布规律:9区足跟内侧(7.86±1.68) kPa,10区足跟外侧(7.47±1.88) kPa,8区中足(4.68±0.71) kPa,1区第一足趾(3.96±1.56) kPa,3区第一跖骨区(3.72±1.43) kPa,4区第二跖骨区(2.87±1.05) kPa,5区第三跖骨区(2.72±1.08) kPa,2区第2~4趾(2.64±1.25) kPa,6区第四跖骨区(2.42±0.68) kPa,7区第五跖骨区(2.13±0.87)。左足底最大应力值、最大压力时间积分值与最大压力值分布规律一致。右足最大应力值、最大压力值、最大压力时间积分值分布规律基本与左足一致。 结论 半蹲式着陆足底受力左右足一致;足底足跟部受力最大;足底内侧受力大于外侧,易导致足内外踝骨折。

     

    Abstract: Objective To observe the rule of plantar dynamics in Chinese parachutists at landing. Methods The maximum stress, maximum pressure, contact area, pressure-time integration value of 12 active duty parachutists from“ August 1st” Skydiving Team were measured using the German Pedar-X system when they jumped off from a 1.5-meter high platform. The left and right plantars were divided into 10 regions according to the conventional criteria and their dynamics parameters were recorded. The rule of dynamics change in each region was observed. The dynamics values in different regions of the left and right plantars were compared. Results The distribution of the maximum pressure in left plantar was as follows: the maximum pressure in left plantar of medial heel in region 9>that of lateral heel in region 10>that of middle foot in region 8>that of the first toe in region 1>that of the first metatarsal area in region 3>that of the second metatarsal area in region 4>that of the third metatarsal area in region 5>that of 2-4 toes in region 2>that of the fourth metatarsal area in region 6>that of the fifth metatarsal area in region 7 (7.86±1.68 kPa vs 7.47±1.88 kPa vs 4.68±0.71 kPa vs 3.96±1.56 kPa vs 3.72±1.43 kPa vs 2.87±1.05 kPa vs 2.13±0.87 kPa). The distribution of maximum stress and maximum pressure-time integration value was consistent with that of the maximum pressure in left plantar. The distribution of maximum stress, maximum pressure and maximum pressure-time integration value in the right plantar was consistent with that of those in the left plantar. Conclusion The pressure of left and right feet is similar at half-squat landing. The pressure of plantar and heel is the highest. The pressure of medial plantar is greater than that of the lateral plantar, thus easy leading to fracture of medial and lateral ankles.

     

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