Limits to Flexibility -- The "Hard Stop"

One of the more interesting things you see in yoga class is that some very experienced and flexible practitioners have particular poses in which they cannot seem to make any progress. The most startling example for me is when very flexible people just can't get any further down in Upavista Konasana, or a seated straddle forward bend.

In this pose, you sitting down with straight legs open wide, and bending forward between thems. For most people, this is much easier than bending forward with the legs together. Almost everyone can flex at the hips more with the legs open. How do you know you're flexing at the hips and not in the back? Think of folding forward with a perfectly flat back and straight legs -- that's a 'pure' flexion in the joint.

I think the joint flexion with legs open is greater mostly because the hip socket is typically more open when the leg is out to the side a bit. Though surely soft tissue (muscles, tendons, and ligaments) are involved as well.

As I said before, most people feel much more open at the hips, much more able to move forward in Upavista Konasana than in Paschimotanasana. But then certain people, including some very flexible people, can hardly move forward at all. And some of these people have been trying for years. I ask them about it, and it doesn't seem to them like it's a question of muscle flexibility -- i.e. it doesn't feel like something they just need to stretch. Instead, it feels more like what I call a "hard stop" -- hitting some kind of firm boundary where there's just no going any further.

By the way, 'hard stop' is a term I came up with, so you probably won't hear it anywhere else.

For me, a hard stop is when your range of flexibility is limited by either joint mobility or ligament. Think of the hip joint. It's a ball-and-socket joint, and very, very snug. This joint is amazing, it supports all our weight all day every day. The thigh bone has the ball inside the joint, and then a long straight bone coming out from there (simplifying quite a bit -- there's also a little branch coming off to the side, I think the lesser trocanter.) The ball sits in the socket, which is like a cup. What's important for "hard" flexibility is the shape of the cup. If the thigh bone hits the edge of the cup, that's it, it's not going any further. Period. Any further movement of the thigh just moves the cup, or the pelvis. (And chances are it's not going to move too far.) This is the best example of a "hard stop".

I used to think that the problem that some people have in upavista konasana was in the shape of the hip socket, that for these people bone was hitting bone, and that was that. But then I noticed that some of these people can do baddha konasana just fine. It seems to me that the relation of thigh bone to pelvis is pretty much exactly the same in the two poses, so it seems that the bone-on-bone 'stop' is not happening for people with very different flexibility in these two poses. Instead, it's probably some ligament in the thigh. This is something I need to research more. (Sorry! Tthis isn't meant to be authoritative. It's a blog, after all, not a textbook.) If anyone has any ideas on this, please post a comment.

There aren't that many examples of hard stops that I can think of. For me, I get a pretty dramatic hard stop when lying on my back and bringing one or both knees into the chest. I bring the knee up to a point, flexing entirely in the hip joint, and then there is a point at which it won't go any further without bringing the pelvis along. You know when this happens because the tailbone lifts and the low back starts to come along for the ride. We all experience a hard stop when doing a supine twist, lying on our back. You bring one knee up, and start to pull it across the body. For a while the lifted thigh moves entirely in the hip socket. But then at some point the hip socket comes along, you lift that whole side of the pelvis, and you come into the twist. (Note -- there is great variation in the range of motion in the hip socket in this direction. Most men can barely make the center line of the body before the hip lifts up, whereas some women and the occasional man can bring the knee six or eight inches across the body with the pelvis still totally level on the ground.)

There are other obvious hard stops having to do with bones. You can only bend you knees or elbows back so far before bone hits bone. Some people have a total hard stop in the ankle joint, in the front -- the bones at the top front of the ankle hit each other (I don't really remember the configuration, but I remember there are a number of bones there!). And when bone hits bone, you're just not going any further without doing some damage.

Most of the other 'stops' in flexibility are 'soft stops'. For instance the arm. The arm socket is very very loose, as you might guess. And there's tons of ligaments and tendons holding things together there. But the ligaments in the shoulder are pretty weak, apparently, and really there are only a few (if I'm not mistaken). So mostly it's tendons and muscles limiting your range of motion. And tendons and muscles stretch. So when you're in down dog, and you're trying to drop your chest forward through your arms (in effect bringing your arms back further behind you), it doesn't feel like a hard stop. It feels like this is something you could probably stretch. And chances are, it is. Though of course take care -- it's very easy to strain a tendon in the shoulder. In fact, this is I think the most common musculo-skeletal injury that medical types face, shoulder injuries, most of which are strained tendons. (I know -- I have a long-lingering mild tendonitis in my right shoulder.)

But ligaments just don't stretch like muscles or tendons, and the bigger and more powerful the ligament, the less it stretches. Ligaments (at least for people over 20 or 25 years old) are very tough, like hard plastic, whereas tendons are a bit softer, like soft plastic. It's not a perfect analogy, but think of ligaments as stretchable as the plastic in a bottle, and tendons as stretchable as the plastic in a six-pack holder. And muscles stretch even more, like big thick rubber bands. (Very thick! It's not that easy to stretch muscles, as we all know.) The ligaments of the hips are really, really strong, as they need to be. As adults we really can't stretch these at all. When we're younger it is possible. Some dancers will stretch their hip ligaments when they're young, to increase their range of motion. And some of these dancers will have some serious back or other physical problems when they get older.

So I think the hard stop is this -- when bone hits bone in the range of motion of a joint, or when you're testing the limits of a ligament, especially one of the powerful ligaments of the big joints.

It seems to me that the idea of the hard stop is anathema to most yoga people. And I understand why. You don't want to approach your yoga practice saying "oh, I can't ever go any further in this pose because that's just the way my body is built." You want to be able to work towards improvement, and you want to believe you can improve.

But I don't agree that everyone should believe that everything is possible. For some people, fine, they can keep striving and not be disappointed when progress is slow or non-existent in certain areas. But for other people, lack of progress can be very discouraging, and can lead to just giving up on yoga (or whatever pursuit.) It's really a matter of mental disposition, and you need to know your own mental disposition. If you're susceptible to discouragement, keeping the concept of the 'hard stop' in mind can be helpful.

Another reason to keep the hard stop in mind is that in yoga there's also the risk of believing a little too strongly in willing your way through everything. The body only will open (or strengthen) so fast (if at all), and if you don't respect the limits of that opening or strengthening, you risk hurting yourself by forcing yourself too far into a pose. Here you risk tearing tendons, tearing muscles, or straining ligaments. (You could tear a ligament I suppose, but muscles and tendons usually go first.)

There's this condition that yoga people in New York refer to as "Yoga Butt". You have a long, lingering pain at the bottom of your butt. And guess what, it's hamstring tendonitis, almost certainly, caused by trying too hard to stretch the hamstrings. I had it about six or eight years ago, it lasted about a year. Lots of others I knew had it. Because we were New Yorkers, strivers, we were going to improve. So we pushed ourselves hard in our stretches, and tore our hamstring tendons.

So I like the idea of the hard stop, even if it really doesn't come up that often, because it tells us that, hey, not everything is a matter of will and effort. There are some things that we're not going to improve, because that's just how our bodies are formed. And, as with just about everything in yoga, this is a little microcosm of life. Sometimes will and effort will get us places, and sometimes they won't. This is the oldest of old ideas, and one of the biggest "big issues" in life, but it's something that we americans, and especially we new yorkers need to remind ourselves.