(单词翻译:单击)
But although it happens passively, arm swinging plays an important role in making your stride more efficient. It does this by counterbalancing your torso and hips and keeping them from twisting and bobbing too much. Holding your arms still against your sides while walking requires twelve percent more energy than if your arms are allowed to swing naturally. Forcing your arms to swing in sync with the leg on the same side of your body uses a whopping twenty-six percent more energy than normal walking. Even when walkers had their arms strapped to their sides, so no muscle control was required to keep them still, they used seven percent more energy than when their arms could swing freely. This suggests that arm swinging is not just a passive byproduct of walking, but actually makes walking easier.
尽管挥胳膊是被动发生的，但是挥胳膊在走路中起着很重要的作用。挥胳膊会抵消膝盖和屁股的阀作用，防止它们过度扭曲或挥动。如果走路时你把胳膊放在体侧不动，这比挥动胳膊走路要多消耗百分之十二的能量。如果强迫胳膊和腿向同一方向挥动，会比正常走路多消耗百分之二十六的能量。即使走路时将胳膊绑在体侧，不需要肌肉来保持胳膊不动，也比挥动胳膊是多消耗百分之七的能量。这表明挥动胳膊不是走路的副产品，而是让走路变得更容易。
plays an important role in 在……起重要作用
counterbalance v. 使平衡; 抵消
whopping adj. 巨大的
strap vt.(用带子)捆扎
byproduct n. 副产品
