Part of my fitness routine involves standing for 20 minutes with the knees ever so slightly unlocked. The goal of this routine, theoretically, is to build up the so called "postural" muscles, which are the host of small muscles used to fine tune posture.
I have been finding it difficult to stand that long without my legs vibrating with that twitch that occurs when you have overexerted a muscle, indicating that I am using some of my large muscles in a position where they have remarkably low mechanical advantage.
Are there any small muscles which are used to keep the knees ever so slightly bent (5 degrees at most), or is that entirely handled by large muscles. If there are, then I know I need to try to determine how to innervate them. If there are not, I either need to rethink how I approach this standing, or I need to supplement with more traditional exercises (like squats) until I have the strength.