Stretching and relaxing
I can touch my toes now. With straight legs.
This is a bit of a big deal for me, having had stiff (or short) hamstrings since youth. However, in recent years, I’ve slowly stretched, bit by bit, until I could touch my toes with slightly bent legs. (yes, I know that stretching is the point, not toe-touching) But then I had a revelation: shift my weight slightly to my heels.
Why? I’ve found that I need to stretch with relaxed muscles. If I’m stretching something, it doesn’t make sense to tense it at the same time, so stretching the same stuff I’m using to hold myself up (by tensing) is counterproductive, isn’t it? Specifically, if I had my weight on the balls of my feet, I’d be using my calf muscles to hold me up more than I would if I had my weight towards my heels, so releasing the calf muscles should make them more flexible, or less resistant.
(While doing Zhan Zhuang, I found the role of the thighs and calves in the weight shift. It may be obvious to students of body mechanics, but not to schlubs like me.)
So. When touching my toes, I shift the weight more towards my heels, my calves relax, and the whole superficial back line (SBL) is relaxed just a bit more, and I can get a bit more length out of myself and get a better stretch. When the legs are straight, the entire SBL gets stretched, and not just the back, according to Myers (the author of Anatomy Trains).
More stretching? More stretching.