The Foot Mechanic

A new way of thinking about your feet

We tend to think of our feet in only one dimension:  the-looking-down-at-your-foot-from-above-dimension.  (You thought there were only 3 dimensions, didn't you?) This plane is the most familiar:  the top-view plane:

There's the profile plane:

And then there's the head-on view (also called the transverse plane):

Anyway, the five metatarsals (if you don't know what or where metatarsals are, read this post) move in this transverse, or head-on, plane when you step on your foot.  And they don't all move the same direction.

Look carefully and critically at the foot and you will notice it can be divided into two distinct sections:  what Eric Franklin calls an "ankle-foot" and a "heel-foot". 

Top view:

   

  Bottom view:

 

The first 3 metatarsals (rays 1-3) are related to the talus and we can call this the ankle-foot; while rays 4 & 5 relate to the heel (calcaneus) and voila!  It's the heel foot.  

Here's the profile view:

...and the head-on view:

The heel-foot and the ankle-foot function somewhat separately although they are (obviously) very reliant on each other for stability. The metatarsals don't move forward/back or swing like pendulums... they rotate along the long axis.  Now because: 

-- the 1st-3rd rays move with the midfoot (cuneiforms and navicular) and the talus in one group

--and because the 4th-5th rays move with the cuboid and heel-bone (calcaneus) in another group, we have a cogwheel effect of the ray.

 This motion occurs each time you step on your foot.  The weight comes down, the gears turn, and the sole of the foot spreads out like a puddle of pancake batter.  Pick your foot up, and the opposite happens.  The gears turn the other direction and the foot domes like a suction cup under suction.

Put a pebble on the floor and try to pick it up with the middle of your foot -- not your toes, the MIDDLE of your foot.  (Yeh, go ahead and massage out that cramp you just got.  I'll wait.)  This is your foot doming.  This happens every time you lift your heel in walking, or push strongly out of the starter's blocks in a race, or jump up in the air.

If you're a dancer, visualize standing on the line between rays 3 and 4 -- this is your perspective.  Rays 1-3 and 4-5 turn en dehors as you releve, and en dedans as you plie.  Imagine that you are lifted up into releve because your foot domes first.  Ahhh.  Isn't that magic?  The power doesn't come solely from your glutes, hamstrings or calf muscles (this is SO important for those who have achilles tendonitis!!!!) -- it can also come from the muscles that live entirely between the tips of your toes and your ankle.

I'll post a video of the embodiment of this movement next time.

Do Certain Types of Sneakers Prevent Injuries? - NYTimes.com

Scientific rumblings about whether running shoes deliver on their promises have been growing louder in recent years. In 2008, an influential review article in The British Journal of Sports Medicine concluded that sports-medicine specialists should stop recommending running shoes based on a person’s foot posture. No scientific evidence supported the practice, the authors pointed out, concluding that “the true effects” of today’s running shoes “on the health and performance of distance runners remain unknown.”

via well.blogs.nytimes.com

The problem with assessing your foot posture and then recommending a certain shoe type (cushiony/soft or supportive/rigid or middle-of-the-road) is that your static foot posture is not necessarily indicative of your foot rhythm in gait.  I tend to overpronate on my right foot and yet I have very high arches.  The shoe salesmen from this article would tell me I need a cushiony shoe because of my overpronation, and yet a rigid shoe for my high arches.  See?  Ridiculous. I'm proud of the researcher quoted at the end of the article because he recommends readers listen to their body and pick running shoes based on that.  Yay!  One point for our side!  Researchers don't usually recommend kinesthetic awareness because they like to measure things, and subjective thoughts are impossible to objectively measure.  

I'm barefoot most of the time because that's what Pilates instructors do, but when I do wear shoes I often pick my Vibram toe gloves.  I just wish they were flesh colored, because I'm 5'2" and wear a size 9 shoe.  I look like *$&%* Minnie Mouse.

 

Your foot is like a suction cup

I'm sure you remember the foot is constructed of arches (from the toes to the heel is the longitudinal arch and from the big toe to the little toe is the transverse arch).  Your weight depresses these arches slightly with every step, just like pressing down on the toilet plunger compresses and deforms the suction cup end.

Instead of sticking you to the floor, however, like this guy...

this spreading or widening of your foot is an energy absorber.  (But wouldn't it be cool to go up the sides of buildings like SpiderMan or a tree frog with your sticky suction-cup feet?)  

When you land a jump, your feet spread out for a couple of very sensible reasons: to distribute your weight over a wider area, to stabilize your landing, to maximally disseminate the landing force.  Don't believe me?  Then try jumping in stilettos. Have you ever tried on new shoes that felt great as long as you were sitting, but absolutely killed when you stood up? That's your transverse arch spreading out like a suction cup.

 It would seem therefore, that pointe shoes do not make any sense.  

 

Take them out of the box and they are very rigid.  They are made of cardboard and glue and covered in satin; some have a carbon-fiber shank in the sole to provide support and longevity to the shoe.  When they are new they are very supportive to the foot, but most uncomfortable. Each dancer has her own personalized method for softening up her pointe shoes: hammering, scraping, closing in a door, warming and reshaping, etc.  

When pointe shoes are new and stiff it is very difficult for the transverse arch to widen and flatten out and you feel it as compression.  Pointe shoes are at their peak in mid-life (just like people).  This is when they have softened enough to allow the toe box to widen a bit for the natural rhythms of the foot and yet not so soft that they can't provide the necessary support for dancing on the tips of your toes.  

You know all this already, though, from your own experience.  Your gut tells you that these Jimmy Choos

 
 

 will probably be more uncomfortable than these Keens

and now you know the biomechanical reason why. 

Gait cycle & the big toe

Every step you take moves through a gait cycle.  Look at the activity of the right foot:  half of the time you are standing on it (stance phase) or swinging it forward and preparing for the next step (swing phase).  The stance phase is made up of  the following events:  heel strike, foot flat, heel off and finally toe off.  Here's an illustration of the gait cycle.

When the foot moves through toe-off (that's the second leg to the right of the shaded leg in the above illustration), normally the big toe is the last bit to leave the ground.  The very last scrap of propulsion your body is going to get is going to come from this moment.  Do you think the big toe can provide much oomph for the rest of the body?  After all, it's not very big....

The big toe is ingeniously designed.  Its tendons are long and thin so that the belly of the muscle is located much higher up, in the calf.  This image is from Thieme's General Anatomy textbook.  It's the mostest awesomest anatomy book ever.  Go visit them at the winkingskull.com or buy it at amazon.

 

This illustration shows the muscle flexor hallucis longus (a long name like that describes the muscle - that is it flexes a joint, it's attached to the big toe, and it's very long) as well as some others.  To find the flexor hallucis longus, look at the base of the big toe and follow that gray tendon upward, behind the inside ankle bone and toward the outside of the calf muscle.  Look at how big the belly of that muscle is!  It's extremely powerful (or at least has the potential to be).  The larger the cross-section of the muscle, the more force it can generate.  As in:

 
Sorry, I got distracted there for a moment.  'K, look at his shoulder, that is the muscle belly of his deltoid.

 

 That's a muscle with a lot of potential for power, and it attaches directly to the bones it affects.  There's no long thin tendon attaching it to a bone far away.  The big toe's ingenious design allows our feet to be bony and light, and yet still have access to power.  Like a long extension cord!  If our feet had to pack the muscle in right on top of the bones, our feet would look like big pillows stuffed with sausages.  Ick.  Nothing fun like this would ever happen again:

Watch sprinters bursting out of the blocks at the beginning of a race; of course that power is coming from the posterior hips and thighs, but don't dismiss the contribution of the big toe and its flexor hallucis longus.  For dancers, this muscle is essential for jumps and releves.

  

 

Bunions

Just what are bunions?  Most people say it's when your big toe "sticks out" or that your big toe "has a bump on it".  Actually, a bunion is when the 3 bones that make up your big toe form an angle instead of staying in a straight line.   

 

(image from Thieme's excellent Atlas of Anatomy - get it if you don't got it)

Bunions are very painful because of the stress placed on the ligaments and because the weird bone configuration creates a difficult shape for shoes.  If you have bunions and you've tried on a pair of stilettos, you know what I mean.  If a bone is jointed to another bone, nature has covered it with thick, smooth cartilage so motion (bending or flexing or whatever) is cushioned, smooth, and gliding.  If the bones don't fit together they way Nature intended, the smooth gliding surfaces are not against each other anymore and, well, Houston we have a problem.

The real tragedy with bunions is that once they start, it's like that stone rolling downhill.   You can see by the illustration above that the angle of the ligaments is a real problem.  The more the big toe joint deviates, the more the hallucis ligaments reinforce the deviation.  (By the way, anything to do with the big toe is labeled hallucis or hallux.  It's from the medieval latin hallex and allux meaning thumb-toe.)  Beneath the ball of your hallux, are two tiny sesamoid bones (from the Greek for sesame, as in seeds) that sit in a bony groove.  They are encompassed within a tendon and act as joint protection and leverage providers.  If they are not positioned properly, their ability to function well is lost.  In the illustration above, you can see the sesamoids are not positioned below the first metatarsal any longer, but have been pulled toward the midline of the foot.  Ouch. Ouch. Ouch.

So, what to do about it?  Well, try to stop bunions from getting worse.  Many people who have bunions have "flattened arches" or pronate too much, so be aware of your weight on your feet and don't stand on the inner border of your foot all the time.  It's not like you don't have a choice, you know.  Strengthening your hip muscles that turn your legs out will help lessen this over-pronation in standing.  Those muscles would be your deep lateral rotators such as the gemelli, obturators, and piriformis, and yeah your glutes too but don't neglect the deep rotators.  Stretch the internal rotators (hamstrings, inner thighs and the tensor fasciae latae) and massage the IT band with a foam roller.  I'll post some descriptions later.

If you have bunions that hurt, stand up and massage the bottom of your foot with a dead tennis ball.  Eric Franklin sells some wonderful massage balls that are softer than tennis balls and very versatile.  He describes many special foot routines in his books that I use all the time with clients and for myself.  His book "Conditioning for Dance" has some great routines, and so does his "Inner Focus, Outer Strength".  

If you really love feet and would like to do a workshop, drop me an e-mail (link at the top of the page) and I'll schedule a Dynamic Foot class for the Carmel/Monterey area.

Grecian Foot - part 2

The Grecian foot can make normal functions difficult, and this goes for dancers and for non-dancers.  Remember, the Grecian foot is the shape where the first toe is much shorter than the second toe. The picture below doesn't truly illustrate a Grecian foot because the first and second metatarsals heads are very close.  However, we will use it to illustrate where the devil those metatarsals are located.

 Remember, the metatarsals are the long bones in the foot. This image is from Thieme's Atlas of Anatomy.  It kicks Netter's butt.  Hard.  Get this book and keep it at your breakfast table for tons of fun and for grossing out your kids over pancakes.

A shorter first metatarsal can cause the second toe to bear more weight than it's been designed for. Imagine a rock embedded in your bicycle tire but still sticking out a little bit.  Each time that rock comes around, you will feel a little "bump" in the road.  The rock is going to bear more weight than the rest of the tire, because it is sticking out and the weight of the bicycle (and you with all those holiday cookies you've been snarfing) cannot be distributed evenly.  Same thing with your feet.  Every time you roll through your foot, as in taking a step, if your second metatarsal is longer than your first, its head will be the rock in the bicycle tire.  Now the first metatarsal was designed for this: its head is larger and thicker, it has two tiny little bones (sesamoids) beneath it that help to maximize leverage and protect the joint margin.  Not so for the second metatarsal.   Depressing, huh.

For dancers with the Grecian shape, balancing on the balls of the feet (demi-pointe) is more difficult because the base of support is very narrow.  Instead of having a bunch of metatarsal heads for a wide base to balance on, like this:

...the Grecian Foot dancer balances with too much weight on the second metatarsal head OR they shift their ankle toward the little toe (in a sickle) to distribute their weight over metatarsal heads 2-5.

However, all of this does NOT mean that people with a Grecian foot shape limp around like Quasimodo haplessly.  No, it just means that they will likely have tight feet, and are likely to supinate or pronate (stand on the outer or inner edges of their feet, respectively).  This client will enjoy footwork on the Reformer with the arch of the foot or the heels on the bar, and the feet in straps series, because the forefoot is open-chain.  This way the 2nd metatarsal head's length has no effect on the rest of the foot.

An ideal solution for walking would be a shoe with a divot cut out of the footbed.  This would be similar to riding that bicycle with the rock in the tire on a road with a tiny divot every so often for the rock to land in.  If it was perfectly aligned, you would no longer feel that bump in the road.  

 A bit impractical, I know, but a good image nonetheless.

Unfortunately, you can't grow your first metatarsal longer, and I sure as hell hope you won't go ask a surgeon to shorten the length of your second metatarsal.  (The doc would refuse anyway.  I hope.)   The best advice I can give you is to stretch out your feet.  If the second metatarsal head is mobile enough that it can move upward, toward the top surface of the foot with each step, that will help to minimize the forces and distribute the weight.  So... stretch your feet!  I'll see if I can post some stretches later.

What's your foot shape?

Curl your toes under as if you are picking up that Frito you just dropped, and draw a dot on top of each knuckle at the base of the toes. (Those are metatarsal heads, if you're interested.) These dots form an arc on the top of your foot.  (When I do this to clients, I use a make-up pencil, so it's easy to wipe off with make-up remover.  Do not use a waterproof eye pencil.  Trust me on this.) 

  

 You can literally connect-the-dots too, if you'd like, to see the arc.

There are a few basic foot shapes:  The greek, the peasant and the egyptian.  (Then there's mine.  It's called LONG and NARROW.  If you're feeling particularly cruel, they're called CLOWN FEET.)  

The differences between these foot shapes is related to the length of the metatarsals, the long bones of your toes.  Sometimes called rays, they look a little bit like the rays of a cartoon sun.  

Or like the rays coming off the Statue of Liberty's crown. More about her later.  

These long bones make up the middle of  your foot.  So although we think our toes are about this long:

They are actually THIS long:

With the Greek/Grecian Foot shape, the big toe's metatarsal is shorter than the second metatarsal. It's called a Grecian Foot, because classic greek statues show this proportion. The Statue of Liberty's toes are shaped like this. See? 
 This guy is carrying his foot fetish thing a BIT too far!  

Next time we'll look at the Egyptian and the Peasant foot. 

Plantar vault

The side view of your foot shows its arch.

Image from Thieme's Atlas of Anatomy - get it if you don't got it.

Its shape is reminiscent of the vaulted ceiling of gothic cathedrals:

P.S. If you love Notre Dame in Paris, check out this photo from Martin Deak's flickr stream.

The arch is one of the strongest shapes in architecture. (The strongest maybe?)  It can support unbelievable forces.  These interior arches of a cathedral ceiling support the weight of a stone ceiling.  Similarly, your foot's arch supports all of your weight.  Each time you step, one arch absorbs your weight; if you are running, those forces are nearly three times your weight.  As long as the structure of the arch doesn't break down, its strength is incomparable.

Foot Design and Long Distance Running

Nice article  from the NYTimes summing up the evidence that humans evolved as long distance runners.  The evidence for our ancestor's marathoning?

-humans have a more efficient cooling system than animals (lots of sweat glands, little body hair, and we don't have to pant)

-Ligaments that act like springs in our lower legs and feet

-The length of our toes (an increase of 20% would double the work-load of the foot)

Check out the article for the complete discussion.

 

Toe Woe Types

Didja know that hammertoes are not the only type of toe woe?  Yep, it's just serendipity that you end up with a hammer toe.  I like that word.  Serendipity.  It sounds like ice cream cones, chance encounters, sunshine while it's raining... it sure as heck doesn't sound like this:  wait.  scratch that.  I was going to post a seriously gnarly shot of a foot with hammertoes but that would NOT be nice for those who are not movement educators or similar.  You'll have to imagine it or google on hammertoe.  It's intense so breathe through your mouth.

Anyhoo, here are those other toe patterns:

The Claw Toe

So called because of the lovely talon-esque profile of this toe.  Yikes!  Can you imagine the forces coming into the ball of the foot?  It's all about force distribution, y'know.  If the forces can't be distributed onto the length of the toe then all of it must go to the ball of the foot and the tip of the toe in this case.

The Mallet Toe

'Cuz it looks like a mallet.  Not a mullet, that's a god-awful hairdo.  (I always hear Journey in my mind when I see a mullet.)  In this toe profile, the ball of the foot is down (that's called extension in this case), the next joint is in neutral and the very last segment is pulled down toward the floor (into flexion).

The Hammertoe

This one is only different from the claw toe because the tip of the toe is lying down here instead of curling under as in the claw.  

This poor foot really needs a tennis ball to stretch out all these parts that are too tight.  Put the ball under your foot and roll your foot over it for a massage that feels great.  If it's too hard, use a dead tennis ball.  If it's still too intense, use an inflated ball like a Franklin ball.