A good, dynamic posture with the harp is the same as in any other sitting or standing activity (read the article on posture). Knowing what good posture feels like in everyday life, together with strengthening your core so that you are better able to maintain this posture is exactly what you bring with you to the harp as well.
Point by point:
- have a stable base, be it from your feet in standing or from your feet and your sitting bones in sitting;
- activate your core to prevent sagging of the back and let your arms move freely;
- have good control of the shoulder stabilisers, keeping shoulder blades nicely flat on your back: no forward rounded shoulders or letting them be pulled up from being tense. But if they do, don't stress, just:
- breathe freely and allow your shoulders to drop (do not pull them down);
- keep your head resting on top of your spine, not pushed forward - even if you have to look at your strings or read music.
When you are playing your harp, you will inevitably have a slightly asymmetrical posture: your left hand stretches further out and down than your right, you will be looking at your strings to the right of you. This asymmetry will not be harmful in the long run as long as you are in otherwise good shape (meaning, being equally strong in both sides of your body, do not habitually carry a heavy bag on only one shoulder or do much computer work with the mouse on the same side et c), vary your activities throughout your day and week, and pause often (more on that in a coming post). Even when touching your shoulder, most of the weight of the harp should be on its own feet, not on you. It is only a positioning touch.
Some people brought up the question on the height of their stool regarding the size of their instrument. How could we find the correct height?
Shoulders in neutral position.
This will of course depend on which model you play on, and what stool you are sitting on. A correct height relationship between you and your harp is one where your head can rest on top of a well-aligned spine and where your shoulders move from a neutral, “dropped” position. The height should also allow for your wrists to be held straight, meaning not bending towards the thumb or little finger. If your harp is too low (even slightly), you may tend to hold your head too far forward, you may start to slouch, and your wrists will be bent towards the thumbs.
This seat is too low: the pelvis tilts backwards, causing the back to curve out and the head is pushed forward.
When seated, you should be able to maintain an active position as well as letting your pelvic bowl provide the foundation for the alignment of the spine: If your stool is very low, you will be sitting with your knees higher than your hips, tilting your pelvis backwards, leading to mis-alignment all the way up to your neck and head. It may not cause you any trouble if playing for a short period, but you shouldn't let this be your habitual playing posture.