肌肉的对准：
只有当肌肉自然地与其根基和关节对准时，肌肉的活动效率达到最佳。自然的对准使得控制你背部、腕部和手指关节的肌肉得到最直接的拉动。
关节的中度活动：
只有当肌肉所控制的关节在适中运动范围之内运作时，肌肉的活动效率达到最佳。（关节）中度的位置和运动使得相关肌肉达到最佳的力度优势。
统一的关节运动方向：
只有手指的三个关节一起进行伸展或收缩时，肌肉的活动效率达到最佳。相比较收缩一个关节而伸展另一个关节而言，同时的伸展或收缩使肌肉的协调得以简化了。
惯性动作：
只有当手指和肌肉运动有充分的惯性动作从而避免产生累积而成的反效率的紧张时，肌肉的活动效率达到最佳。充分的惯性动作意味着，一旦动作已经开始，就不要刻意地去制止动作。
原文：
Four Principles of Muscle Function（Aeron Shearer: Learning the classic guitar Part I, Mel Bay, 1990 ）
Muscular Alignment:
Muscles function most efficiently only when naturally aligned with their base and joint attachments. Natural alignment provides the most direct pull of the muscles that control your back, wrist, and finger joints.
Midrange function of Joints:
Muscles function most efficiently only when the joints they control are operated within their midrange of movement. Midrange positioning and movement provides optimum leverage to the muscles involved.
Uniform Direction of Joint Movement:
Muscles function most efficiently only when three joints of a finger or the thumb are either flexed or extended together. In contrast to flexing one joint while extending another, simultaneous extension or flexion simplifies coordination of the muscles.
Follow-through:
Muscles function most efficiently only when there is sufficient follow-through to avoid a build-up counterproductive tension. Sufficient follow-through means that, once a movement has been initiated, no intentional restraint is applied to the movement.
