What Science Can Teach Us About Flexibility

科学如何引导练习柔韧性

By Fernando Pagés Ruiz

Tendons transmit force by connecting bones to muscle. They are relatively stiff. If they weren't, fine motor coordination like playing piano or performing eye surgery would be impossible. While tendons have enormous tensile strength, they have very little tolerance to stretching. Beyond a 4 percent stretch, tendons can tear or lengthen beyond their ability to recoil, leaving us with lax and less responsive muscle-to-bone connections.

肌腱是使肌肉附着到骨骼上的桥梁，同时承担着力的传导。肌腱相当的稳固，否则那些需要精密协调的动作 -- 比如弹奏钢琴或实施眼部手术 -- 则是完全不可能的。肌腱具有很大的抗张强度，它能承受的伸展度也非常小。一旦伸展幅度超过4%，即会撕裂，或失去回弹力。

Ligaments can safely stretch a bit more than tendons—but not much. Ligaments bind bone to bone inside joint capsules. They play a useful role in limiting flexibility, and it is generally recommended that you avoid stretching them. Stretching ligaments can destabilize joints, compromising their efficiency and increasing your likelihood of injury. That's why you should flex your knees slightly—rather than hyperextending them—in Paschimottanasana (Seated Forward Bend), releasing tension on posterior knee ligaments (and also on the ligaments of the lower spine).

韧带的安全伸展范围比肌腱大一点。韧带负责在关节囊内将骨与骨牵拉在一起。因此，他们在限制关节活动方面发挥很大作用，通常的建议是不要去拉伸韧带。韧带被拉伸的话，会降低关节的稳定性，影响关节的功能，并增加受伤的风险。这就是为什么在双腿背部伸展式 (Paschimottanasana (Seated Forward Bend))中我们应该稍稍弯曲膝盖，而不是绷直它，这样才能释放膝后韧带的紧张（同时也包括下背部韧带的紧张）。 

Muscle fascia is the third connective tissue that affects flexibility, and by far the most important. Fascia makes up as much as 30 percent of a muscle's total mass, and, according to studies cited in Science of Flexibility, it accounts for approximately 41 percent of a muscle's total resistance to movement. Fascia is the stuff that separates individual muscle fibers and bundles them into working units, providing structure and transmitting force.

肌肉筋膜是第三种影响柔韧性的结缔组织，也是最重要的一种。肌肉筋膜占肌肉总重量的30%，而且，根据《Science of Flexibility》，人体运动时，体内的阻力中有41%来自肌肉筋膜。筋膜负责将单独的肌肉纤维分别包绕，再结合为功单位，维系着结构和力的传导。

Many of the benefits derived from stretching—joint lubrication, improved healing, better circulation, and enhanced mobility—are related to the healthy stimulation of fascia. Of all the structural components of your body which limit your flexibility, it is the only one that you can stretch safely. Anatomist David Coulter, author of Anatomy of Hatha Yoga, reflects this in his description of the asanas as "a careful tending to your internal knitting."

伸展带来的好处 -- 有益关节润滑、愈合力、循环系统和灵活性 -- 这些都与筋膜受到的良性刺激有关。在所有对身体柔韧性有制衡的结构部件中，筋膜是唯一可以放心去拉伸的。解剖学家David Coulter，《Anatomy of Hatha Yoga》一书的作者，将瑜伽体位法形容为 -- “对我们肌肉精美外衣的悉心照料”。

Now let's apply this physiology lesson to a basic but very powerful posture: Paschimottanasana. We'll begin with the anatomy of the asana.

现在让我们把这些生理学知识应用到一个非常基础但又十分有效的体式 -- 双腿背部伸展式。先从解剖学来认识一下这个体式。

The name of this pose combines three words: "Paschima," the Sanskrit word for "west"; "uttana," which means "intense stretch"; and "asana," or "posture." Since yogis traditionally practiced facing east toward the sun, "west" refers to the entire back of the human body.

这个体式的名字由三个词组成：西方-“Paschima”，强烈的拉伸-“uttana”，体式-“asana”。因为瑜伽修行者通常面朝东方 - 太阳升起的方向来练习，所以“西方”就意味着身体的背面。

This seated forward bend stretches a muscle chain that begins at the Achilles tendon, extends up the back of the legs and pelvis, then continues up along the spine to end at the base of your head. According to yoga lore, this asana rejuvenates the vertebral column and tones the internal organs, massaging the heart, kidneys, and abdomen.

这个坐立前屈体式从跟腱开始拉伸，伸展了腿部后侧和骨盆，一直向上延展脊椎到颅底。按照瑜伽的观点，这个体式可以滋养脊柱神经并且调节按摩腑内脏。

Imagine you're lying on your back in yoga class, getting ready to fold up and over into Paschimottanasana. Your arms are relatively relaxed, palms on your thighs. Your head is resting comfortably on the floor; your cervical spine is soft, but awake. The instructor asks you to lift your trunk slowly, reaching out through your tailbone and up through the crown of your head, being careful not to overarch and strain your lower back as you move up and forward. She suggests that you picture an imaginary string attached to your chest, gently pulling you out and up—opening anahata chakra, the heart center—as you rotate through the hips into a seated position.

想象一下你在瑜伽教室中仰卧下来，正准备进入双腿背部伸展。双手放松的放在大腿上，头和脊椎都舒适地停留在在垫子上，但意识却没有松懈。跟随老师的引领，慢慢地抬起上身，头顶和尾骨分别向相反的方向运动，向前时要小心，不要给下背部过多的压力。老师可能还会让你想象胸骨上方佛有一条绳索，被温柔地牵引着，向上向前伸展。这样，我们的心轮被慢慢打开。