英语视频听力：奥运项目跨栏（在线收听）

Every athlete battles mental barriers. But this Olympian must defeat physical barriers too: all ten of them!

　　Hi, I'm Dr Greg Wells. Hurdlers are incredible multi-taskers. They have to be. Taking off like they've been shot from a cannon, they must somehow maintain enough control to soar, smoothly, over barriers about a metre high, in rapid succession.

　　So, how do they pull it off? When most of us run, our femur moves through a small range of motion in the hip socket -and in just one direction. But hurdlers train to move their femurs differently: they have twice the range of motion, and rotate in a circle at the same time!

　　The secret is a special stomach muscle called the psoas. It runs from your thigh bone, through your stomach, and up your lower back. Hurdlers lengthen and strengthen their psoas muscle. That lets them whip their trail leg through the entire range of motion with incredible speed.

　　The average person can run 7-10 km/h, but the unique combination of strength and flexibility enables an Olympic hurdler to hit up to 30! The fusion of hip motion and muscle recoil... That's how you leap to gold!

　　中文字幕：

　　每位运动员都要克服心理障碍。而这位奥运选手还必须克服实际障碍，共有十个之多。

　　我是维尔斯博士。跨栏选手是神奇的多面手，他们必须做到。他们起跑犹如炮弹，但又必须保持足够控制力，才能顺畅地越过约一米高的障碍物，一个接一个。

　　他们是怎么做到的呢？我们跑步时，大腿的股骨在髋臼内作小幅度的运动，而且只朝一个方向。但跨栏选手股骨的运动有所不同，活动幅度达常人两倍，同时还可以打圆圈。

　　秘密在于腹部一块叫腰肌的特殊肌肉。腰肌从大腿骨经腹部连到下背部。跨栏选手把腰肌练得更长更强，让他们的跟进腿能以惊人速度，跨出大幅度动作。

　　一般人跑速是每小时7到10公里，而奥运跨栏选手结合劲力和灵活度，可以达到时速30公里。髋部运动加上肌肉回弹，就是夺金之道！