What Science Can Teach Us About Flexibility

科学如何引导练习柔韧性

By Fernando Pagés Ruiz

Remember the cheesy '70s sci-fi flick in which Raquel Welch and her miniaturized submarine crew get injected into someone's bloodstream? To really grasp how Western physiology can benefit asana practice, we need to go on our own internal odyssey, diving deep into the body to examine how muscles work.

还记得70年代的那部科幻大片《Fantastic Voyage/神奇旅程》吗？Raquel Welch 和她的微型飞船被注射进一个人血液系统。为了深入理解西方生理学究竟对瑜伽体位法有何等贡献，我们需要来一场身体内部的探险之旅，开着我们的微型飞船去看看肌肉到底是如何工作的。

Muscles are organs—biological units built from various specialized tissues that are integrated to perform a single function. (Physiologists divide muscles into three types: the smooth muscles of the viscera; the specialized cardiac muscles of the heart; and the striated muscles of the skeleton—but in this article we'll focus only on skeletal muscles, those familiar pulleys that move the bony levers of our bodies.)

肌肉是由多种特殊组织为了实现同一种功能而有机地结合在一起形成的器官，是一个生物学单位。（生理学将肌肉分作三种类型：内脏里的平滑肌、心脏中的心肌、和骨骼上的骨骼肌 -- 在本文中，我们特指骨骼肌，他们就像我们骨架上的轮带，带动机体运转起来。）

The specific function of muscles, of course, is movement which is produced by muscle fibers, bundles of specialized cells that change shape by contracting or relaxing. Muscle groups operate in concert, alternately contracting and stretching in precise, coordinated sequences to produce the wide range of movements of which our bodies are capable.

肌纤维束的牵引实现肌肉的基本功能，他们随着收缩和舒张而改变形状。肌肉群协同作用，轮流地通过精确而有序的收缩或舒张，赋予机体活动的能力。

In skeletal movements, the working muscles—the ones that contract to move your bones—are called the "agonists." The opposing groups of muscles—the ones that must release and elongate to allow movement—are called the "antagonists." Almost every movement of the skeleton involves the coordinated action of agonist and antagonist muscle groups: They're the yang and yin of our movement anatomy.

在骨骼运动中，负责收缩而带动骨骼运动的肌肉，称作“主动肌”；另一些肌肉与之相反，必须舒张并伸展才能允许该动作的形成，这一类叫做“拮抗肌”。几乎所有的骨骼运动都需要主动肌和拮抗肌的协同作用：他们就像是运动解剖学中的“阳”与“阴”。

But although stretching—the lengthening of antagonist muscles—is half the equation in skeletal movement, most exercise physiologists believe that increasing the elasticity of healthy muscle fiber is not an important factor in improving flexibility. According to Michael Alter, author of Science of Flexibility (Human Kinetics, 1998), current research demonstrates that individual muscle fibers can be stretched to approximately 150 percent of their resting length before tearing. This extendibility enables muscles to move through a wide range of motion, sufficient for most stretches—even the most difficult asanas.

虽然拮抗肌的拉伸在骨骼运动中也顶半边天，但是大部分生理学专家都认为，想要增加肢体的灵活性，去增强肌纤维的弹性意义并不大。Michael Alter，《Science of Flexibility 》一书的作者，认为现代研究已经证实肌纤维可以被拉伸到原有长度的大约150%而不断裂。这种延展度足以支持肢体实现大范围动作，甚至包括最难的瑜伽体位。

If your muscle fibers don't limit your ability to stretch, what does? There are two major schools of scientific thought on what actually most limits flexibility and what should be done to improve it. The first school focuses not on stretching muscle fiber itself but on increasing the elasticity of connective tissues, the cells that bind muscle fibers together, encapsulate them, and network them with other organs; the second addresses the "stretch reflex" and other functions of the autonomic (involuntary) nervous system. Yoga works on both. That's why it's such an effective method for increasing flexibility.

如果不是肌纤维限制了我们的伸展，那么是什么？该如何做才能改善呢？关于这个问题的回答有两派观点。第一种学派认为，与其关注肌纤维的拉伸，不如去增加结缔组织的弹性 -- 即那些将肌纤维捆扎成束的细胞组织，使他们更好的与其他组织协调工作。另一种学派则关注“牵张反射”效应和植物神经系统的其他功能。瑜伽的方法恰恰是这二者的融合，因此，体位法练习对于改善身体的柔韧性效果非常显著。

Your Internal Knitting

肌肉的外衣

Connective tissues include a variety of cell groups that specialize in binding our anatomy into a cohesive whole. It is the most abundant tissue in the body, forming an intricate mesh that connects all our body parts and compartmentalizes them into discrete bundles of anatomical structure—bones, muscles, organs, etc. Almost every yoga asana exercises and improves the cellular quality of this varied and vital tissue, which transmits movement and provides our muscles with lubricants and healing agents. But in the study of flexibility we are concerned with only three types of connective tissue: tendons, ligaments, and muscle fascia. Let's explore each of them briefly.

结缔组织（connective tissues）包括各种形态的细胞群，他们将我们身体的各部包绕联合在一起，最后行成一个有机整体。他们是体内数量最庞大的一种组织，交织成复杂的网状，将身体个部分联系起来，又区分出相互独立的解剖学结构：骨骼、肌肉、脏器等等。几乎每个瑜伽体位都会调动这些形态各异的结缔组织，他们的细胞质量得到提高，而同时，这些组织带动肌肉运动，又供给供肌肉必须的润滑剂与愈合剂。和肢体柔韧性相关的结缔组织有三类：肌腱（tendons）、韧带（ligaments）和肌肉筋膜（fascia）。让我们来简要的了解一下他们。