Summer Flip-Flops May Lead to Foot Pain

By Tara Parker-Pope

　　Flip-flops are a mainstay of summertime footwear, but they can be painfully bad for your feet and legs, new research shows.
　　Researchers from Auburn University in Alabama studied the biomechanics of the flip-flop and determined that wearing thong-style flip-flops can result in sore feet, ankles and legs.
　　“We found that when people walk in flip-flops, they alter their gait, which can result in problems and pain from the foot up into the hips and lower back,” said Justin Shroyer, a biomechanics doctoral student who presented the findings to the recent annual meeting of the American College of Sports Medicine in Indianapolis.
　　For the study, the researchers recruited 39 college-age men and women and asked them to wear flip-flops or athletic shoes. They then had them walk a platform that measured vertical force as their feet hit the ground. A video camera measured stride length and limb angles.
　　Flip-flop wearers took shorter steps and their heels hit the ground with less vertical force than when the same walkers wore athletic shoes. People wearing flip-flops also don’t bring their toes up as much as the leg swings forward. That results in a larger angle to the ankle and a shorter stride length, the study showed. The reason may be that people tend to grip flip-flops with their toes.
　　Mr. Shroyer notes that he himself owns two pairs of flip-flops, and the research doesn’t mean people shouldn’t wear them. However, flip-flops are best worn for short periods of time, like at the beach or for comfort after an athletic event. But they are not designed to properly support the foot and ankle during all-day wear, he notes.
　　（From The New York Times June 5, 2008）

夏天慎穿人字拖鞋

〔美国〕塔拉•帕克-波普  于桂芝　译

　　虽然人字拖鞋在夏季很流行，但是一项新的研究表明，人字拖鞋的害处在于它会造成脚部和腿部的疼痛。
　　来自阿拉巴马州奥本大学的研究人员对人字拖鞋进行了生物力学分析，发现穿带状人字拖鞋会导致脚部、脚踝和腿部的酸痛现象。
　　生物力学博士奥斯汀•施罗耶，最近在印第安纳波利斯市举办的美国运动医学会年会上展示了此项研究成果。他说：“我们发现脚穿人字拖鞋的人在行走时，会改变走路的姿态，这种改变的结果就是脚部以上直至臀部和腰部的疼痛。”
　　为了这项研究，科研人员召集了处于大专院校年龄段的39名男女，要求他们穿上人字拖鞋或是运动鞋走过一个平台。当实验对象的脚部触及平台地面时，平台测量出向下的作用力。另有一架摄像机测量步伐的长度和腿部运动的角度。
　　穿人字拖鞋走路时，人们的步子会缩短，脚后跟触及地面时产生的向下的作用力小于同一实验对象穿运动鞋时产生的作用力，脚趾向上的幅度不及腿部向上摆动的幅度。该研究表明，以上情况使得脚踝活动幅度加大，步长变短。其原因可能在于人们趋向于用脚趾紧紧夹住人字拖鞋。
　　施罗耶提到自己有两双人字拖鞋，该研究并不意味着不应穿人字拖鞋。然而，人字拖鞋最适合于较短时间内穿着，比如在海滩上，或是运动赛事后出于舒适的目的。但是，他也指出，全天候穿着时，人字拖鞋在设计上不能对脚部和脚踝起到适当的支撑作用。
　　（译自美国《纽约时报》2008年6月5日）