時差N小時:走路時為什么要甩胳膊?(下)

But although it happens passively, arm swingingplays an important role in making your stridemore efficient. It does this by counterbalancingyour torso and hips and keeping them from twistingand bobbing too much. Holding your arms stillagainst your sides while walking requires twelvepercent more energy than if your arms are allowed toswing naturally. Forcing your arms to swing in syncwith the leg on the same side of your body uses awhopping twenty-six percent more energy thannormal walking. Even when walkers had their armsstrapped to their sides, so no muscle control was required to keep them still, they used sevenpercent more energy than when their arms could swing freely. This suggests that armswinging is not just a passive byproduct of walking, but actually makes walking easier.

盡管揮胳膊是被動發(fā)生的，但是揮胳膊在走路中起著很重要的作用。揮胳膊會抵消膝蓋和屁股的閥作用，防止它們過度扭曲或揮動。如果走路時你把胳膊放在體側(cè)不動，這比揮動胳膊走路要多消耗百分之十二的能量。如果強迫胳膊和腿向同一方向揮動，會比正常走路多消耗百分之二十六的能量。即使走路時將胳膊綁在體側(cè)，不需要肌肉來保持胳膊不動，也比揮動胳膊是多消耗百分之七的能量。這表明揮動胳膊不是走路的副產(chǎn)品，而是讓走路變得更容易。

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.(用帶子)捆扎 byproduct n. 副產(chǎn)品