I did a deeper version of horse stance this morning during Five Golden Coins. I couldn’t sustain it all the way through Eight Pieces of Silk, but I’ve gotten a start on strengthening my practice.
The challenge in a deeper horse stance is that the tailbone wants to pop outwards, and achieve a sitting posture in mid-air. But in tai chi, you want the tailbone tucked under, so it’s not a target for attack (you wouldn’t want anyone to kick your ass, would you?). So horse stance, even though it’s hard on the knees and ankles and thighs and calves, isn’t really about building leg strength.
It’s about building abdominal strength. And that’s pretty difficult. I mean, I have an extra pouch of fat on my middle, rather like a kangaroo has a pouch in the cartoons. That fat is constantly hanging forward and down (sorry if this is disgusting). And the goal of a proper horse stance is to strengthen the abdominal wall so that all that extra mass is flush against the body, and the tailbone is pointed down.
Every half-inch or so that the knees are bent strengthens that abdominal wall, and makes these muscles stronger. And the fact that I can sink down another couple of inches suggests that these abdominal muscles are already stronger than they were when I began. Even if they don’t look it.