健康生活:运动前不宜拉伸

Most of us grew up hearing that we should warm up with a stretch. Strike and hold a pose, such as touching your toes, for 30 seconds or more, we were told, and you'll be looser, stronger and injury-proof.
我们是听着这样的告诫长大的：运动前要先做拉伸运动来热身。摆出姿势并保持——比如用手触脚尖——30秒或更久，然后我们的身体就可以变得更柔韧、强壮、不易受伤。

But anyone who follows fitness science — or this column — knows that in recent years a variety of experiments have undermined that idea. Instead, researchers have discovered, this so-called static stretching can lessen jumpers' heights and sprinters' speeds, without substantially reducing people's chances of hurting themselves.
不过，所有关注运动科学（或本专栏）的人都知道，近年来有不少实验都证明，运动前拉伸并不高明。研究者发现，所谓的静态拉伸会让跳高运动员跳得更低、短跑者跑得更慢；而且还不能显著降低运动受伤的风险。

Now, two new studies are giving us additional reasons not to stretch.
现在，又有两个新研究为我们提供了“不要拉伸”的新理由。

One, a study being published this month in The Journal of Strength and Conditioning Research, concluded that if you stretch before you lift weights, you may find yourself feeling weaker and wobblier than you expect during your workout. Those findings join those of another new study from Croatia, a bogglingly comprehensive re-analysis of data from earlier experiments that was published in The Scandinavian Journal of Medicine and Science in Sports. Together, the studies augment a growing scientific consensus that pre-exercise stretching is generally unnecessary and likely counterproductive.
其中一项发表在本月的《力量与训练研究杂志》(The Journal of Strength and Conditioning Research)上。研究称：假如你在举重前进行拉伸运动，你会感觉举的时候比预期力气更小、踉踉跄跄。此结果与另一项由克罗地亚科学家对以往实验进行的广泛深入的再次分析不谋而合，该项研究发表于《北欧医学与运动科学杂志》(The Scandinavian Journal of Medicine and Science in Sports)。这两项研究巩固了一个日益强大的科学共识：通常情况下，在锻炼前做拉伸不仅没必要，还可能起反作用。

Many issues related to exercise and stretching have remained unresolved. In particular, it is unclear to what extent, precisely, subsequent workouts are changed when you stretch beforehand, as well as whether all types of physical activity are similarly affected.
锻炼与拉伸之间的很多关联尚不明朗。特别是：人们不知道准确来说，拉伸到什么程度会使接下来的锻炼受到影响；也不知道是否锻炼前拉伸对一切体育活动都产生相似作用。

For the more wide-ranging of the new studies, and to partially fill that knowledge gap, researchers at the University of Zagreb began combing through hundreds of earlier experiments in which volunteers stretched and then jumped, dunked, sprinted, lifted or otherwise had their muscular strength and power tested. For their purposes, the Croatian researchers wanted studies that used only static stretching as an exclusive warm-up; they excluded past experiments in which people stretched but also jogged or otherwise actively warmed up before their exercise session.
为了让新研究涉及范围更广，同时解释上述问题，克罗地亚萨格勒布大学(University of Zagreb)的科学家梳理了上百个以前进行过的实验。这些实验中，志愿者先做拉伸运动，然后或跳、或扣篮、或举重或进行肌肉强度与力量测试。基于研究目的，他们只选择用静态拉伸作为唯一热身运动的实验；剔除了那些让志愿者在锻炼前除拉伸外还慢跑过或做过其他动态热身的实验。

The scientists wound up with 104 past studies that met their criteria. Then they amalgamated those studies' results and, using sophisticated statistical calculations, determined just how much stretching impeded subsequent performance.
最后，符合他们选择标准的共有104项研究。他们综合这些研究的结果，利用复杂的统计计算方法确定拉伸对锻炼的影响程度。