Option 1: upright sitting

选择一：挺拔端正地坐着

This is probably the posture¹ you think of as "good" posture. The defining feature of this option is that the trunk is upright.

这很可能是你所以为的“良好”坐姿。这种坐姿的标志性特点是后背直直的。

A key component² of upright sitting is that the feet can comfortably rest on a surface, whether the floor or a footstool. This position also makes it easy to adjust posture within the chair (fidget) and change posture to get out of the chair.

端正坐姿的一个关键要素是双脚能够舒服地放在平面上，无论是地板还是脚凳。这一姿势能够让你轻松地在椅子里调整坐姿（可以动来动去），也方便你改变姿势从而能够从椅子上站起来。

It's also important the arms hang down from the shoulders vertically³ with elbows by the trunk, unless the forearms are supported on the work surface. Holding unsupported arms forward requires the muscles connecting the shoulder and neck to work harder. This often results in muscle fatigue⁴ and discomfort⁵.

同样重要的是，胳膊要从肩部笔直地垂下，手肘靠在身子旁边，除非前臂搁在工作台上。把没有支撑的胳膊放在身体前面需要联结肩膀和脖子的肌肉更用力，这通常会导致肌肉疲劳和不适。

The head should be looking straight ahead or a little downwards⁶. Looking upwards⁷ would increase tension in the neck and likely lead to discomfort.

头应该直直地向前看或稍微向下看。向上看会增加颈部的紧张感，也容易引起不适。

This posture is useful for common office tasks such as working on a desktop⁸ computer.

这一坐姿适用于普通的办公室工作，比如在台式机前工作。

Option 2: forward sitting

选择二：身体向前倾的坐姿

The defining feature of this posture is that the trunk is angled forward, and the arms are rested on the work surface. Allowing the thigh⁹ to point down at an angle may make it easier to maintain an inward curve in your lower back, which is suggested to reduce low back stress.

这一坐姿的标志性特点是身体向前倾，胳膊靠在工作台上。让大腿以某个角度向下倾，可以更容易地让下背保持向内弯曲的姿态，据说这样能缓解下背部压力。

For a time, special chairs were developed to enable the thigh to be angled downwards, and usually had a feature to block the knees, stopping the person sliding off the angled seat base.

过去曾研发出一种特殊椅子，能让大腿的角度向下倾，而且通常带有阻挡膝盖的设计，阻止座位上的人顺着倾斜角度往下滑。

By perching on the front of an ordinary chair and resting your elbows on the work surface, you can use this posture to provide variety in sitting. This posture is useful for tasks such as drawing or handwriting on a flat work surface, either with paper or a touch screen device.

坐在普通椅子的前端，把胳膊靠在工作台上，这样坐可以让你的坐姿更多样化。这种坐姿适用于在平面工作台上用纸或触摸屏设备画画、写字。

Option 3: reclined sitting

选择三：靠着椅背坐

The defining feature of the third option is the trunk is angled backward, supported by the chair's backrest. Back muscle activity is lowest in this posture, as some of the upper body weight is taken by the chair.

第三种坐姿的标志性特点是，身体向后倾，靠在椅背上。这样坐，后背的肌肉活动是最少的，因为上半身的一部分重量被椅子抵消了。

This position may reduce the risk of fatigue in the back muscles and resultant discomfort. But sitting like this for hours each day may result in the back muscles being more vulnerable to fatigue in the future.

这种坐姿可以降低背部肌肉疲劳和由此引发不适的风险。但每天连续数小时这么坐，可能会导致后背肌肉在未来更容易感到疲劳。

This posture is useful for meetings and phone conversations. But it doesn't work well for handwriting or using a computer as the arms need to be held forwards for these things, requiring neck and shoulder muscle activity likely to result in discomfort.

这种坐姿适合开会和电话会谈，但不适合写字或用电脑工作，因为做这些事的时候胳膊要向前放，采取这种坐姿完成需要颈部和肩膀肌肉活动的工作会引发不适。