这几十年来，坊间都会看到核心肌群(Core Muscle)、核心力量(Core Strength)、核心稳定度(Core Stability)等，你也可以在网路上找到数以千记的训练与器材来改善核心的能力，但在进行之前，先来了解什么是核心控制(Core Control)。来看看书上的描述：
There are many muscles in the midsection. All muscles do it shorten. When they shorten, one end of the muscle moves towards the other. Some of there muscle like your rectus abdominis(腹直肌)(your six-pack, 六块肌), your internal and external obliques(腹内外斜肌), and your erector spinae muscles(竖嵴肌) cause us to move.
For example, when you contract your six-pack, you either flex your torso foward towards the pelivs, or tuck your pelvis underneath to flatten the lower back.
In either case, the rectus abdominus contraction produced a distinct movement – a change in position.
(在任何一种情况下，腹直肌的收缩产生了远端四肢的移动 – 位置的改变。)
一般训练六块腹肌指的就是腹直肌的部份。
The problem is that the rectus abdominus and your obliques are more fast twitch, not postural muscles.By definition, you cannot depend on them to hold your posture in line all day or during a run. They will fatigue and your position and economy will change.
(问题在于腹直肌与腹斜肌更属于快缩肌，不是用来维持身体姿势的肌肉群。定义上，你无法依赖这些肌肉群来维持你整天作息的姿势或是跑步的动作。当他们疲劳时，你的姿势及效率将会改变。)
关于何谓快缩肌(Fast Twitch)可以参考“肌肉耐力与力量的差别”。
Other muscles in the midsection don’t really have much of an effect on changing position of your upper body or lower body.The transversus abdominus(腹横肌), the multifidi(多裂肌), and the pelvic floor(骨盆底肌) are more concerned with keeping things in position.(腹横肌、多裂肌、骨盆底肌更着重在于固定的工作上。)
The multifidi are thin muscles in the back of your spine. They have the greatest proprioceptive nerves(本体感受神经) of any muscle in the body. They monitor the position of each and every vertebrate in the spine. As you move, they tell your brain exactly how much each vertebrae moved on another vertebrae. Some of this information goes to our brain, and some of it goes in reflexes.
Your transversus has a different job. It runs around the body similarl to the way a corset(马甲) wraps around the body. If you tighten the corset on a woman’s dress, it prevents movement. When transversus fires, it doesn’t change the position of the body either.
The true definition of core control is how well you can keep your upper body stable on the lower body.
(核心控制的真正定义是如何将上半身保持稳定于下半身。)
关于腹横肌的部份，可以参考“[书摘] 腰痛，从核心肌群训练开始”文章的说明啰。过度训练“移动肌(Movers)：腹直肌、腹内外斜肌、竖嵴肌”与虚弱无力的“稳定肌(Stabilizers)：腹横肌、多裂肌、骨盆底肌”，在核心控制上会产生重大的问题。
The key feature of core control is not strength, but timing. Research shows that good core control is actually a feed-forward response.
(核心控制的关键在于“时间(Timing)”，而不是在于“力量(Strength)”。研究指出，好的核心控制能力其实是一种事先诱发的反应或称前馈反应。)If I move my arm out to the side, my brain knows that moving the limb away from my center of mass will change my balance point, and it will naturally kick on my true core stabilizers 40 milliseconds prior to me moving my arm. In the lower body, 110 milliseconds before I move my leg, my brain kicks on to keep my body stable and in line.
Proper stabilization depends on proactive, not reactive control.
(稳定度取决于前瞻(预应)的控制，而非反应的控制。)
从下面的图形中有说明，正常的核心稳定度是与时间有关。大脑知道四肢的移动会改变身体的平衡点，因此动作发生之前40~110毫秒，大脑会发送讯号给内部腹部肌群，来维持身体的稳定。
但是若慢生疼痛、姿势不良(Posture Dysfunction)或是背部疼痛持续超过四周的时间，身体就会丧失前馈肌肉的控制能力。核心肌群虽然被触发了，但时间点太迟了！
在书上谈到一位常跑步的青少女Michelle的例子，做了Single Leg Squat与Single Leg Bridge的动作评估之后，发现是右侧髋关节缺乏稳定度，侧向与旋转的髋关节控制能力有问题，进而造成髌股关节综合症(Patellofemoral Pain Syndrome)。
她开始上网找到了许多的训练方式，开始进行一连串的“Side-lying leg lifts”、“Single leg squats”、“Elastic band hip abduction”等动作，但五周之后，髌股关节综合症还是依然存在着。Why？她从评估的结果中得知自己缺乏髋关节的控制能力，并且进行特定的训练来改善它，但为何没有改善呢？这问题的答案就在于她“姿势不良”，她有青少女常见的症状Female Adolescent Texting Syndrome(F.A.T.S)：
虽然她针对缺乏的肌肉进行独立的训练，但肌肉的运作并不是独自进行的，肌肉群是透过精密的控制交互的进行合作配合，来完成动作。若她无法达到适合的姿势与核心控制，她的髋关节与骨盆会一直处在不稳定的状态，控制髋关节的肌肉也是不稳定的。
因此一位物理治疗师建议，她需要由内而外来进行改善，先由核心肌群的稳定度开始，让髋关节肌群有较好的基底在进行运作，并且建立畅行无阻的前馈控制，以确认稳定度发生是在触地之前。
《Timing is everything.》
书中有谈到，除了因为姿势不良、肌肉不平衡之外，跑者常见的受伤大多数因为稳定肌群缺乏训练，因此在强化跑步的肌群与速度之前，先着手训练稳定肌群的控制。
文章来源：山姆伯伯工作坊
