长跑致足部黑踇趾损伤的生物力学机制研究

Study on the Biomechanical Mechanism of Foot Bruised Toenail Injury Caused by Long-Distance Running

目的:探究长跑前后足部生物力学改变对黑踇趾损伤风险的影响,揭示长跑致黑踇趾损伤的生物力学机制,基于黑踇趾损伤预防理念进行鞋头设计并验证其防护效果,为长跑黑踇趾损伤预防和防护跑鞋研究提供支撑。方法:选取10名男性半职业马拉松跑者为受试者进行跑步测试,采集其跑前、5 km跑后即刻及10 km跑后即刻的足部形态特征、足部各区域温度、大踇趾主观舒适度以及足-鞋相对运动距离等参数,进行单因素重复测量方差分析,以揭示长跑致足部黑踇趾损伤的潜在生物力学机制。基于黑踇趾损伤生物力学机制进行鞋头抬高的防护跑鞋设计,其中原型跑鞋的鞋头高度为65.8 mm,长度为85.5 mm;防护跑鞋的鞋头高度为79.5 mm,长度为85.8 mm。采集跑鞋优化前后的大踇趾主观舒适度、大踇趾-鞋面接触力以及三维有限元模拟仿真计算的大踇趾应力,并进行独立样本分析,以期对防护跑鞋的黑踇趾损伤预防效果进行验证。结果:随着跑步距离增加,10 km跑后的足前掌宽度以及足弓高度显著下降。所有足部分区的温度在5 km和10 km跑后均显著上升,其中10 km跑后的大踇趾足背区温度上升明显,与5 km跑后即刻呈现显著差异。与此同时,跑后的大踇趾主观舒适度显著降低。着地即刻的足-鞋相对位移在10 km跑后较5 km显著增加,而增加的距离在支撑中期较跑前以及5 km跑后又显著降低。相较于原型跑鞋,防护跑鞋在提升大踇趾主观舒适度的同时,使得大踇趾-鞋头作用力在两者接触期的0~80%显著减小,且应力分布更加均匀。结论:10 km跑后足前掌宽度、足弓高度显著下降,大踇趾足背区温度明显上升,伴随跑者大踇趾主观舒适度降低和足-鞋相对位移增加,表明长跑后足部形态与功能改变可能是黑踇趾损伤的潜在生物力学机制。基于鞋头抬高设计的防护跑鞋能够在提升跑者主观舒适度的同时,降低接触力,并且使大踇趾区域应力分布更加均匀,可以有效降低因长跑引发的黑踇趾运动损伤风险。

Objective:To determine the potential effect of foot morphology changes on the injury risk of bruised toenail during longdistance running,and to further optimize the design of running shoe structure and comprehensively verify its effects on preventing bruised toenail injury.Methods:Ten male recreational runners participated in this study,the foot morphology,foot temperature,perceived comfort,and the gap length in the sagittal plane were collected at before(baseline),immediately after 5 km and 10 km of treadmill running.In addition,the design of toe box was optimized based on the biomechanical mechanism of foot bruised toenail injury,where the original shoes has a toe height of 65.8 mm and a length of 85.5 mm;the new-designed shoes has a toe height of 79.5 mm and a length of 85.8 mm.The comfort perception,foot-shoe contact forces,and contact pressure were collected across different running shoes to confirm the effectiveness of injury prevention.Results:The width of forefoot and arch height were reduced greatly after the 10 km run.Foot temperature was increased significantly after 5 km and 10 km running,and the temperature of dorsal hallux was significantly higher after 10 km running than that of 5 km run.Regarding to the hallux comfort,the perceived score was significantly reduced after 5 km and 10 km running.In addition,there was a significant increase in gap length after 10 km running during one running gait cycle,followed by a notable decrease upon reaching midstance.Compared with the original shoes,the subjective comfort of new-designed shoes was increased,and the new-designed shoes significantly reduced the force during the contact phase by 0~80% and achieved a more uniform pressure distribution.Conclusions:The reduced width of forefoot and arch height,increased foot temperature,accompanied by the decreased subjective comfort and increased gap length during long-distance running would potentially responsible for bruised toenail injuries.Meanwhile,running shoes designed with an elevated toe box increased subjective comfort while reduced contact force and achieved a more uniform pressure distribution,which could reduce the risk of bruised toenail injury effectively.