Have you ever noticed how the pelvis seems to drift backwards in standing forward bends, especially Uttanasana? Sometimes you get an assist from a teacher who pushes the pelvis forward from the sacrum to align the hips and leg bones back over the ankles. Oftentimes, however, when they remove this assist, your pelvis drifts back again . . .
|Pressing the big toes into the mat|
If you’ve had this experience, here’s a cue you can use (for yourself and your students) to align the pelvis and the bones of the lower extremities perpendicular to the floor. As always, warm up with Surya Namaskaras. Then take Uttanasana. Engage the quadriceps to straighten the knees. This aids to release the hamstrings through reciprocal inhibition and helps to align the bones that form the knee joint. Now press the fleshy part of the big toes firmly into the mat. Feel how this brings the pelvis forward and the legs upright—the desired position of the pose.
This is an example of balancing opposites in yoga. When you flex forward, the pelvis will naturally drift back a bit to counterbalance the weight of the trunk so that you don’t fall over. This angles the bones of the legs away from perpendicular to the floor. Ideally, you want these bones aligned so that their long axes are perpendicular to the floor—which has several beneficial effects. First, bones have tensile strength that is similar to cast iron and compressive strength similar to reinforced concrete. “Stacking” the bones so that gravity is directed down through the long axis allows you to use this passive bone strength rather than active muscular force to maintain the pose. Second, aligning the bones in this manner more optimally spreads the joint reaction forces evenly across the cartilage of the knee. If you are tilting the leg bones back, these forces are more concentrated at the front of the joint.
Why Does This Work? Physics . . .
The knees, ankles, and toes operate differently than the hips and trunk. Flexing these joints moves the extremity towards the back plane of the body, whereas flexing the hips moves the extremity towards the front plane of the body.
How Can the Small Bones of the Big Toes Accomplish This? Physics . . .
The contractile force of these smaller muscles is magnified by the long lever arm of the leg. The big toes act as a fulcrum to propel the pelvis relatively forward and bring the leg bones upright. Put another way, the pelvis has to come forward to counterbalance the force of the big toe flexors.
Here’s the Anatomy . . .
|The flexors hallucis longus and brevis of the big toe.|
The flexor hallucis longus originates from the lower two thirds of the back of the fibula and the interosseous membrane between the tibia and fibula. It inserts onto the base of the distal phalanx of the big toe. This means that it crosses multiple joints, including the ankle, subtalar, and metatarsophalangeal joints—i.e., it is a polyarticular muscle. Accordingly, it can act to flex any of the joints it crosses.
The flexor hallucis brevis originates from the medial and intermediate cuneiform bones and a ligament that runs between the calcaneous and cuboid bones. It then divides into a medial and lateral head. These insert onto the base of the proximal phalanx of the big toe via the medial and lateral sesamoid bones, respectively. (The sesamoid bones are mobile structures embedded in the ligaments). The flexor hallucis brevis acts to flex the metatarsophalangeal joint of the big toe and also supports the longitudinal arch of the foot.
Use Your Big Toe in Other Poses . . .
|Using this technique in Ardha Chandrasana.|
Try this technique in one-legged asanas like Ardha Chandrasana and these poses. This is another example of the “portability” of scientific principles between the asanas. Combine this tip with the cue for balancing opposites in the foot and ankle. You can also add the technique from our first post on working with the deltoids to deepen Uttanasana. Finally, augment the diaphragm by activating the accessory muscles to breathe deeply in your practice.
|An excerpt from "Yoga Mat Companion 1 - Anatomy for Vinyasa Flow and Standing Poses".|
|An excerpt from "Yoga Mat Companion 1 - Anatomy for Vinyasa Flow and Standing Poses".|
Thanks for checking in. Be sure to visit us on Facebook. See you for the next post, when we’ll illustrate an effective way to correct hyperextended joints.
All the Best,
I'm afraid you have made a few errors here.
Firstly stacking the bones puts them in compression not tension. Tension is a pulling force and not a pushing force. Compression is what a column must resist if it has weight balancing over top of it. Tension is what the rope feels in between two groups at a tug of war.
Secondly bone has between 1/2 and 1/3 the tensile strength of steel depending on the type of steel. I didn't quickly find the data on steel for compression but I would still bet it is stronger than bone.
Of course these are minor points.
The major point is why does pushing the big toe down cause the pelvis to move forward.
Leverage has nothing to do with it. Leverage alone (if the body existed in a simplistic lever and pull environment) would actually move the pelvis backwards. Think of what happens when you push down on a gas pedal. If you can imagine that the gas pedal is held still you should feel that your back would push into the seat not be pulled out of it.
The reason pushing the big toes into the floor moves the pelvis forward happens because of the way the body works as a whole. The righting reflex (not sure if that is the correct term) senses that the body is about to topple over and then causes many of the flexors in the front of the body to contract and pull the body forward.
If you were to stand in Tadasana and push your big toes into the ground you would start to tip backwards until the shin muscles would flex and cause the exact reverse of what you are suggesting. The lift of the toes would cause you to have the pelvis move forward.
The action that you are looking for is the same, just the explanation is off.
I hope that is helpful.
I think the point I’m making is that bones have great passive strength and it is better to align them to take advantage of this. I don’t think it’s particularly relevant to yoga, but I will try to get permission to post a table illustrating tensile, compressive and sheer strengths of various materials such as different bones—traveling at the moment so may be a few days. You use all three strengths at any given time.
I am indeed referring to leverage with the FHL and FHB (big toe flexors). These muscles do not have great cross-sectional area compared with the gluts or hamstrings. The reason small muscles like these can lever the pelvis forward is they are using the long lever arm of the legs—which gives them a mechanical advantage over the hamstrings and gluteus maximus. In fact, if you contract your gluteus maximus, you will also move the pelvis forward, same with the hams (try it). The big toe flexors are much more efficient to do this for two reasons. First, they are not stretching and so can contract more efficiently than the hams or gluts (stretching muscles have fewer cross bridges, a.k.a. active insufficiency). The other reason a couple of small muscles can counterbalance the pelvis is that they are at a mechanical advantage.
You tilt back when you press down the big toes in Tadasana because there is no counterbalancing flexion of the hips or trunk--can also sway the pelvis forward as you point out to balance. You will also tilt back if contract the gastroc, hams or gluts—for the same reason. That is how I figured out the cue.
Thanks for stopping by—I posted the tensile strength I’m pretty sure of as well as the compressive strength—cast iron and reinforced concrete.
All the Best,
Thought a bit more about your comment and I think it is also a valid way to explain this cue. The pelvis has to come forward to counterbalance the force pushing it back from the toes flexing. The toes flexing can generate enough force because of the mechanical advantage etc. Thanks for giving me this different perspective on it.
I have often heard the cue to press through the "big toe mound" (the first big toe joint/ball of the foot). But it sounds like you're saying that one should press through the toe itself. Is that correct? And if so, how do you press through the big toe without gripping or clawing with that toe?ReplyDelete
Muscle fibers can do one thing - contract. This may lead to tension or compression at different spots. So basically you have a lever pulley system, however the positions of the levers and the pulleys in the body are not fixed. Depending how the different bones of the body are positioned in relation to each other the force vectors can travel in different directions. I.e standing in Uttanasana, Tadasana or sitting in a car means three different relations between, foot, lower leg, upper leg, pelvis, trunk. Further, another thing I believe is of importance here is "Euler buckling". I.e. depending on how e.g. compressive force is applied on a column in relation the the centre of gravity and depending on if the endpoints are fixed or not the column will bend (ever so slightly) in different patterns and force will travel in different patterns.
In uttansana both the feet/ankles and the pelvis are in a fairly fixed position.
And then we have the matter that Ray frequently points out - reciprocal inhibition - different positions will activate the Golgi tendon organs in different ways and created different force chains.
I am not a Facebook person. Am I still eligible to try to win the series? I am not even sure what "profile" I have.ReplyDelete
Many thanks. cer
On pressing the big toe without clawing, gently and evenly press the fleshy part of the distal (last) phalanx of the toe into the mat. Try it with your thumb first on the edge of a table. It does not take much force to have the effect--not necessary to claw. This is different from pressing the ball of the foot, which would use different muscles.
Also to Anon--for the contest go to:
I'm on the road at the moment--thanks for posting, I want to look closer at your comment tonight.
Hello again Ray (and Byron)ReplyDelete
Here´s an article from the journal of Electromyography and Kinesiolog adressing a little the matter of different force transmission pathways.
Best Regards Sven
i came to this article much later than i usually like, but have found it kind of nice to see how the commentary, adds a great deal of further interest to the main articleReplyDelete
big toes, little muscles, grand effects!
seems like a parallel to my learnings since i started reading your work ray ;-)
stuck my big toe in a big new pile of knowledge, found my own knowledge muscles were smaller than i'd even realized, but wow, what grand effects already, really...
i've even "begun" to introduce these concepts into my classes, and am enjoying being able to share such special insights
thank you much, safe travelings (if you're still on the road), and i assume you're having fun ;-) - so keep up the good work!
Thanks for the comment--glad to hear you are integrating the material into your classes. Believe me, students appreciate it. Still on the road, thanks for wishing safe travels.
All the Best,
Hi Bandha Yoga,ReplyDelete
Your info and dialogue is really interesting, thank you very much. Free access appreciated!
Would you be able to take detailed look at the neck please? Target work for developing optimum length on the different muscles of the neck, alignment tips, and info specific to poses, especially standing poses, headstand, backbends
Many older yoga people have neck troubles.
Thanks for your suggestion--I will look into it. Very complex subject but something to address.
Wonderful as always. I sincerely appreciate your experience and educated point of view both as a student and a teacher. The visuals are great as well. Keep up the Great work!ReplyDelete
I have enjoyed reading the above...I have found that when I float the heal [2or 3 mm] of the floor in all the standing asana and even sitting asana [energetically] I then pause........................in pausing the Hips finely release, this would complement your big toe finding. as it grounds the front part of the heal. This is how human are meant to walk and run, the ball of the foot first then the heal. Heal striking when we walk is bad for the body. thanks for this info.ReplyDelete
best wishes Malcolm Pollock.
I enjoy your articles. They help me to enhance my teaching. When I tried to find the Chakra poster and ebook I keep getting an error message. Can you advise me?ReplyDelete
Thanks for alerting us to the link. I will check on it on Monday.
THIS IS SO SO GOOD! Thanks.ReplyDelete
I question the "as always, warm up with sun salutations" I think the original sun salutations need to be updated in the light of modern lifestyles and biomechanical research. I would suggest cat cow, bird dog, plank and side plank instead. See Back Mechanic, by Stuart McGill, PhD page 111 ff.ReplyDelete