時差N小時:走路時為什么要甩胳膊？(上)

Have you ever wondered why we swing our armswhile walking? It’s a curious phenomenon, sincearms don’t play an obvious role in locomotion. Youcan still walk normally when your arms are full ofgroceries or with your hands in your pockets, so whydo we do it? Isn’t it a waste of energy? Twoindependent studies, both published in 2009, mayprovide some answers to this mystery. The Answer…Using a combination of mechanical models,computer simulations and tests with human walkersand runners, the studies concluded that armswinging just sort of…happens. In other words, you don’t need muscles for your arms to startswinging, although you can use muscles to swing your arms higher or more forcefully. If you’rewalking and your arms are hanging relaxed by your sides, they will normally swing in syncwith the opposite leg. That is, your right arm swings forward when your left leg steps forwardand vice versa.

你想過為什么走路時我們要甩胳膊嗎?這是很有趣的現(xiàn)象，因為胳膊在走路時并沒有明顯的作用。當你手上拎著東西或將手插進口袋里，你仍然可以正常走路。那我們?yōu)槭裁匆Ω觳材?是在浪費體力?兩項發(fā)布在2009年的獨立研究也許能為此提供答案。答案……利用機器模型，電腦模擬和對走路的人和跑步的人測驗，研究得出：走路時甩胳膊只是一種自然而然的動作。換句話說，你不需要胳膊上的肌肉來甩胳膊，盡管你可以用肌肉來甩胳膊甩得更高些或有力些。走路時如果你的胳膊垂在身體側面，無事可做，那胳膊就會朝腿運動的相反方向甩動。

phenomenon n. 現(xiàn)象 locomotion n. 運動 independent adj. 獨立自主的 simulation n. 模擬conclude v.得出結論 sync n.同時發(fā)生