Core Muscles

As a former modern dancer (hence the performance art aspect of my 400 IM), the most important and deepest of the core muscles is the psoas major/minor. It extends from your twelfth thoracic vertebra/first lumbar vertebra (I think) and goes deep deep deep through your trunk down to connect to the top of the femur (leg bone). "The two psoas muscles, major and minor, are perhaps the most important of all the muscles in determining the human, or upright, posture . . . ." (From THE THINKING BODY by Mabel Elsworth Todd; an old book but very important for dance training, uh, in my time.) For dance (and swimming) these are the deepest and most stabilizing muscles with which others work, along the length of the spine, but the psoas muscle is the deepest and most critical to balance and breathing. What is so critical about these muscles is that they go from the back of the spine through the pelvis to attach at the front of the top of the leg bones. So they are very central to strength. This is why dancers can show such strength with long-held high legs, among other aspects of balance and strength (ballet); ballet dancers are using these very very deep abdominal muscles, not the leg muscles, though of course these too are activated. I also keep getting psoas cramping/tightening (I slump, very bad posture) after swimming. A good release is to lie on the floor on your back and have one knee bent, the other leg lengthened and relaxed, and breathe into the extended leg, imagining the connection from the ribs down through the body to the top of the hip sockets releasing. By having good posture (not military, but engaged, in the Pilates sense) in everyday life, your psoas muscles will be stronger. This is one area I think that land training with stability balls or Pilates or any strengthening exercises that emphasize using these deep muscles will truly aid swimming balance, breathing, and overall "connection" of the stroke. I am not there yet. There is another old book we used in dance class that was written by a professor of dance at Julliard, called HUMAN MOVEMENT POTENTIAL. It has a lot of imagery to use to help you bypass your "thinking" about core strength and allowing your bones to fall into least-resistance alignment so that your physical movements are efficient, as they were designed to be. Haven't quite figured out how to translate the imagery into my swimming practice. But, long post short, I would say the psoas muscles are the key core muscles to think about not only for strengthening but also in everyday life for posture and walking. One aside, the "Y" ligament that attaches your hip in the front to your pelvis, is the strongest ligament in the body, because it prevents your pelvis from being able to bend backward so that you don't suddenly find yourself on the ground, hips on sidewalk, legs totally behind you. (I loved studying this stuff in dance class.) Thanks for reading! If you did....

:cane::bed:Just curious, but are these "core muscles" fast twitch or slow twitch? Or both? If both, just how much: 50/50, 60/40, 75/25 or depends on age? In my case, I'm probably 100% slow twitch?

Thanks for that wonderful description Isobel! I had an hour and a half session with my massage therapist, and it turns out both my Psoas and my Rectus Abdominus were strained. But after a rehab week of long slow pulling with a pull buoy, couple with my massage therapist, I'm just about totally recovered and back to full-blown practices. The Psoas is a pretty deep muscle, and I needed an expert guide to help me be able to find it and isolate it. Do a google search and click on some of the pictures that come up near the top -- they give a good view of where they are.

I'm suddenly reading about the importance of core muscles in various media. The latest Runners World has a story, as does Men's Health. I never thought about it when I ran when I was younger, but now even for running a strong core can help keep your balance better, legs in the proper position, etc. But I find it especially helpful for swimming. I'm not fast, but do feel much more smooth in the water now that my core has improved.

Thank you isobel for the muscle education :) Could you please tell me how I would feel these muscles distinctively? In what movement/position would I be mainly using them? (Just trying to know what you were talking about and see if I have made use of those muscles in swimming) You can feel them by lying on the floor and putting your hand right above your hip joint. Many people don't know where their hip joints are (forgive me if times have changed), but your hip joints are on either side of your pubic area, the hollows where the top of your femur "rests" in a little cup). So your hip joints are about a small-hand's width apart from each other. Everyone can feel their psoas when it is engaged, even if it is weak. It is a palpable muscle in that area, right above the hip joint. So press your back against the floor, contract your abdominal muscles by so doing, and push your hand into the area right above your hip joint. You should feel a muscle flex, or form into something that feels a bit ropelike. Then relax and it will disappear. It may be very small (which would indicate it is not very strong), as in, it may feel maybe just 1/2 inch thick, or it may feel like a nice thick rope, an inch or so (strength!). (I am relying on memory from dance classes from long ago, but this is my memory.) The psoas is a very deep muscle of the trunk, but you can feel it where it connects at the hips. In one dance class I was told to always be engaging my psoas muscle, except when I was asleep or if I was dead. This is a basic premise behind "pure" Pilates training as well (there are a lot of spinoffs of Pilates now, but those who are truly certified will have taken possibly years of training to understand how to engage these deep muscles). I'm going to see if I can attach an illustration of the psoas and quadratum lumborum so you can see how deep they are and how essential they would be to strength. One thing I remember from dance class was that if you are doing situps and your stomach goes up as you do them, then you are engaging superficial muscles. To engage your psoas you need to be pressing into the floor, including your abdominals. One amazing demonstration of the power of the psoas I saw was that you can engage it for strength without fully engaging the quad. Imagine the rest that would give your (my) poor legs when swimming. The woman demonstrating was doing pelvic bridges and lifting one leg out straight; her quad was pretty relaxed, so she was initiating the movement from her psoas. I am not there yet. As I said, I slump. OK. Let's see if I can get this illustration uploaded. Also, as far as is it a fast twitch or slow twitch muscle, I don't know. I started to research it but found myself reading about dissected rabbits and I didn't want to read about them. I did see an interesting link that turned into an ad, but it was saying that any type of training that is repetitive and lasts longer than 10 minutes is going to be training your muscles to be slow twitch. You can train your muscles to be fast twitch, according to this article/ad, the way martial artists do (however that is), such that they can kick and break a board in seconds. Anyhow, I always thought fast/slow twitch was genetic, and that people are born one way or the other, that slow twitch muscles have more "red meat" (blood?) for aerobic exchange, while fast twitch muscles are more like white meat (lots of Krebs cycle/ATP energy exchange). Thus in freshman biology we, sigh, mashed up bees' wings to see that they were loaded with mitochondria, where all the energy exchange takes place (memory here again), which was why they could move their wings so fast. I digress. Psoas illustration presented below. Don't know if you train this to be fast/slow twitch. Seems to me it would be slow because it is a stabilizing muscle but I am not a scientist.

Thank you isobel for the muscle education :) Could you please tell me how I would feel these muscles distinctively? In what movement/position would I be mainly using them? (Just trying to know what you were talking about and see if I have made use of those muscles in swimming)

nhc: My guess is the psoas major/minor are equally important to all strokes, no more or less important. They are your furnace of power. Now if someone else might know something about this, it does seem somewhat intuitively at this ungodly hour of 1:43 a.m. that for breaststroke and butterfly, the psoas might be more of a fast-twitch muscle, in that it is engaged more quickly, is my guess, like, ka-boom! for each pulse forward of these strokes, whereas for back and free, it is lengthening and providing stability, still the furnace of power, allowing lower, less central muscles to do less work, but perhaps the speed of its contractions are slower for the longer axis strokes. I am speaking out of the coma of insomnia. Is there someone on this bulletin board who might know more about (a) whether the psoas can be trained to be fast-twitch, (b) if it is used in different ways for the more powerful contractions required for fly and breaststroke and (c) if you can call on it to be both fast-twich and slow-twitch.? It's such a deep muscle that consciously I don't know if you can have any control over how you are using it as you swim. I think you have to train it in everyday activities, and strengthen it on its own, and then I don't know exactly how it translates into swimming. In dance class, as I said, we both trained it specifically, but we also used many many images as a way for the "conscious" mind's way (inefficient) to get out of the way of the body's natural way (very efficient) to stack all those bones up in alignment so that gravity was minimized in destabilizing you. Since it is late, here are a few images for daily life: Walk as if you are Alice in Wonderland, feel your head and neck grow taller and taller. Imagine you are a doll and your arms are falling out of their sockets (releases tension in arm sockets). Imagine you are walking supported by one of those baby swings, so the baby swing is holding your pelvis and your legs just follow along. Imagine you have a long tail that is dragging behind you as you walk (lengthens your back). Imagine there is an ice cream cone between your ribs and your abdomen (this does address the psoas); see that the cone is tipped forward (the ice cream part); bring the ice cream part up so that it is straight and in line with the cone part, thus connecting your upper body to your lower body. A million images we used to help us get our bones into alignment as nature intended, and get gravity out of the way. As I said, how this translates into swimming, I haven't figured out. Certainly the more you derive your power from the center of your body, the less you will be relying on your arms and legs for strength. So rotation certainly would require solid strong psoas muscles, which would allow perhaps your legs and arms to be more relaxed and stay stronger longer. Look at a lot of the Paralympians: some with no legs, or shortened legs, or no arms, or shortened arms, yet at the Paralympics at Beijing, some very fast times. They clearly are using central trunk muscles like the psoas. OK. Enough. A new career: Pilates swimming... zzzzzzzz

Thanks for the info. Always wanted to know where the core muscle is. So the Psoas group is basically the achilles' for upright support, strength and balance? From it's appearance, it looks like they simply provide structural strength of lower trunk and legs. God definately must have a PHD in mechanical engineering.:)

I think the psoas also is important with breathing, since it's close to the diaphragm. I think it is your major source of power for entire body. For dance we studied the "X" axis of movement, where right arm connects all the way down across the body to left leg, all governed by central power of psoas. Actually I might be making that part up but it seemed that all we talked about if we weren't dancing were the psoas and the X axis, and keeping those diagonals connected fingertip to toe. I think that could apply to swimming. Yes, I believe God or whatever is an amazing engineer. When I was learning about movement mechanics for dance, and how efficient the body is if we can prevent gravity/bad habits from bending us out of shape, I was also taking a class in Samuel Beckett's plays, where every character is pretty much paralyzed. Interesting combo. Also interesting in that Beckett's uncle was champion Irish swimmer. I *suppose* the paralysis of his characters was perhaps metaphoric. I can identify with the play Happy Days where at first the characters can move their arms, necks, and heads, yet are reminiscing about former times of greater freedom, and at the end of the play they are buried up to their chins and can only move their eyes, and still they reminisce. Cheerful class, yah! Glad I danced before and after! Actually was glad to dance and forget about stupid psoas and X axis because sometimes so much self-conscious thinking got in my way. There are times to let it go and just feel the motion, I think. True with dance technique, true with swimming technique, though some on this forum may disagree.

Many thanks isobel for the description and the picture! One question: are these muscles used more in long-axis strokes (free, back) than in short-axis? Do you think they are used the most when rotating the body?