What causes that is a tight chest and weak back muscles.

造成这种情况的原因是胸部紧绷和背部肌肉无力。

What do I do at the gym? I try to work on specific back and lower back muscles but it's quite difficult.

我在健身房做什么？我通常专门练背肌和腰背肌，不过非常难。

Some of these exercises put too much strain on the back muscles.

【strain】这些健身动作中有些令背部肌肉负担过重。

They also use their scratching time as a chance to stretch out their back muscles, so they can stay nice and loose for all that scurrying about.

它们还利用抓挠的时间来伸展背部的肌肉，因此可以在疾驰的时候保持优雅和放松的状态。

Again bend the knees as generously as you like here, feeling that nice stretch in the lower back muscles, and then bring the fingertips to the earth.

再一次，你可以在这里尽情地弯曲膝盖，感受下背部肌肉的拉伸，然后把指尖放在地面上。

So you want to focus on the back muscles that hug your spine — they're called the erectors and they hold you erect.

所以你要专注于拥抱你的脊柱的背部肌肉——它们被称为竖直肌，它们让你保持直立。

Now I don't mean bodybuilder back muscles; there's actually a lot of huge big gladdened guys that do have this issue and they look kind of like gorillas, right?

现在我指的不是健美运动员的背部肌肉；实际上有很多非常高兴的大家伙确实有这个问题， 他们看起来有点像大猩猩， 对吧？

Also the meat hook hasn't penetrated all the way though your body, instead it's pierced through the back muscles just under your shoulder, so bleeding out isn't an immediate threat.

此外，肉钩并没有完全穿透你的身体，而是刺穿了你肩膀下方的背部肌肉， 所以流血并不是直接的威胁。

A sprinter will accumulate more fast-twitch muscles in her legs through continuous practice, enabling her to quickly, if briefly, pick up the pace, whereas back muscles contain more slow-twitch muscles to maintain your posture all day.

一个运动员可以通过持久的练习在腿部积攒更多的快速转换肌肉，从而让她更快，更简单的提速。然而背肌包括了更多的慢转换肌肉，来长久地保持你的姿势。