SoftScience “The Terrain Ultra Lyte” shoe update:

Introducing “The Terrain Ultra Lyte”.  Fresh off the UPS truck today
and just unboxed ! Uber excited. Wearing them right now. Dang, zero drop
with good cush. I could run in these babies ! And I will just to try,
even thought that is likely not their intended purpose.  Gorgeous roomy
toe box. True to fit. These feel like a favorite pair of worn in
favorite leather gloves …  they are soft cotton canvass right out of
the box.  I don’t think i even need to wait a few days, they
should have a label that says “pre-worn in”. I may have just found yet
another new favorite weekend casual shoes, I will save my Altra
Everyday’s for work. I can see where the thinking came when the partners
brought their wisdom over from Crocs (only the best parts were brought,
the materials, from what i can see).  
Removable, washable Trileon™ insole, non-marking, slip-resistant outsole
Ultra lightweight, a pair in size 10 weighs just 1.6 lbs. (that is per pair !)

*Welcome to Soft Science. one of our Podcast sponsors. Because we believe in them.

Update one day later:

Some have been asking about this shoe. I
think they have done something unique here. This shoe is about 6 oz,
yes, that is seriously uber light. That means there is no room for
stabilizing rigidity factors in this shoe. It appears to be a well
thought out “outsole” and a soft cotton canvas upper. That is it. If you
need control, this shoe may not be for you. The outsole however offers a
nice wide foot print with some flare of the sole out from the foot
(look at their website, look at the shoe from behind), and that in
itself offers stabilizing over something compared to like a glove type
Now, on to the insole:
I know what the website says, a
“minimal heal to toe elevation”. I emailed the guru over as Soft
Science. I have been told they are zero drop and after wearing i believe
they are, and if not, maybe a millimeter ? I have sensitive feet, I
wear zero drop all day long at work because I can. Not everyone can and
this is important to note.
I do not have any info outsole thickness
of this particular shoe, the foot does recede somewhat into the outsole
that you see, so there is not a tremendous amount of stack height as
portrayed in photos, some of that is the outsole lipping up to grab onto
the shoe’s upper.
TRileon Insole:There is a VERY mild arch
contour, not as much as in crocs (as one person asked) but it is present
and mild. If you have a flatter arch, you will feel it, but, Trileon is
uber cush so it is not offending at all. If you have a normal arch
posture, you may not even notice it, it is that subtle.
there feels like a 1-2 degree or 1-2 mm varus forefoot post, i have
pretty sensitive feet and can tell these things readily, i may choose to
grind this down on the insole, it wouldn’t take much to do this. If you
take out the insole and put it on a hard floor and stand on it, you
will notice the subtle forefoot varus posting of the foam. And if you
put the insole in your hands and pinch finger tips together at the 1st
metatarsal head and 5th met. head you will notice the thickness
difference. * It is not much, but it is there. Some people can really
benefit from it since many feet are have a slight FF varus. Some may not
notice it at all. I did notice it because my forefoot is not varus’d at
all.  I noted it less so when the insole was in the shoe so it may be
off setting a slight depression in the outsole shell. I am not sure, so
do not quote me on this. For most folks, this is “princess and the pea”
subtle jibber jab talk and is not worthy of noting.  But we are shoe
geeks and some of you want to know about peas.
To be clear, I like
this shoe so far, very much actually. It will be on my feet all week and
all weekend……..many weekends.  Soft, uber light, no break in, zero
drop, good looks, minimal, wide platform, ….. things i like and things
that are important to me. The question is, “is it for you ?” That is up
to you.  Nice work Soft Science.
-Dr. Allen

Fore foot types: Differences between forefoot varus and forefoot supinatus.

Certainly this can be a contraversial topic. Perhaps this will help clear up some questions.

Supination of the forefoot that develops with adult acquired flatfoot is defined as forefoot supinatus. This deformity is an acquired soft tissue adaptation in which the forefoot is inverted on the rearfoot. Forefoot supinatus is a reducible deformity. Forefoot supinatus can mimic, and often be mistaken for, a forefoot varus. A forefoot varus differs from forefoot supinatus in that a forefoot varus is a congenital osseous deformity that induces subtalar joint pronation, whereas forefoot supinatus is acquired and develops because of subtalar joint pronation (1).

A Forefoot Varus induces STJ pronation whereas a Forefoot Supinatus is created because of STJ pronation (2).

As the foot experiences increased subtalar joint (STJ) pronation moments during weightbearing activities (as in forefoot supinatus) , the medial metatarsal rays will be subjected to increased dorsiflexion moments and the lateral metatarsal rays will be subjected to decreased dorsiflexion moments. Over time, this increase in STJ pronation moments will tend to cause a lengthening of the plantar ligaments and medial fibers of the central component of the plantar aponeurosis and a shortening of the dorsal ligaments in the medial longitudinal arch. As a result, the influence of increased STJ pronation moments occurring over time during weightbearing activities will tend to cause the following (3):

1. An increase in inverted forefoot deformity.
2. A decrease in everted forefoot deformity.
3. A change in everted forefoot deformity to either a perpendicular forefoot to rearfoot relationship or to an inverted forefoot deformity.

More on the forefoot tomorrow evening on Biomechanics 309. Join us!

1. Clin Podiatr Med Surg. 2014 Jul;31(3):405-13. doi: 10.1016/j.cpm.2014.03.009. Forefoot supinatus. Evans EL1, Catanzariti AR2.



Forefoot Varus or Forefoot Supinatus?

Forefoot varus is a fixed, frontal plane deformity where the forefoot is inverted with respect to the rearfoot. Forefoot varus is normal in early childhood, but should not persist past 6 years of age (i.e. when developmental valgus rotation of forefoot on rearfoot is complete, and plantar aspects of fore- and rearfoot become parallel to, and on same plane as, one another (1)

Forefoot supinatus is the supination of the forefoot that develops with adult acquired flatfoot deformity. This is an acquired soft tissue adaptation in which the forefoot is inverted on the rearfoot. Forefoot supinatus is a reducible deformity. Forefoot supinatus can mimic, and often be mistaken for, a forefoot varus. (2)

A forefoot varus differs from forefoot supinatus in that a forefoot varus is a congenital osseous where a forefoot supinatus is acquired and develops because of subtalar joint pronation.

“Interestingly, only internal rotation of the hip was increased in subjects with FV – no differences were present in hip adduction and knee abduction between subjects with and without FV. The authors nevertheless conclude that FV causes significant changes in mechanics of proximal segments in the lower extremity and speculate that during high-speed weight-bearing tasks such as running, the effects of FV on proximal segments in the kinetic chain might be more pronounced.”

We wonder if the folks in this study had a true forefoot varus, or actually a forefoot supinatus (3).

The Gait Guys

1. Illustrated Dictionary of Podiatry and Foot Science by Jean Mooney © 2009 Elsevier Limited.

2. Evans EL1, Catanzariti AR2. Forefoot supinatus.
Clin Podiatr Med Surg. 2014 Jul;31(3):405-13. doi: 10.1016/j.cpm.2014.03.009.

3. Scattone Silva R1, Maciel CD2, Serrão FV3. The effects of forefoot varus on hip and knee kinematics during single-leg squat. Man Ther. 2015 Feb;20(1):79-83. doi: 10.1016/j.math.2014.07.001. Epub 2014 Jul 12.

Forefoot Varus Anyone?

Forefoot varus appears to move the center of gravity medially while walking. Nothing earthshaking here, but nice to see the support of the literature.

“The most medial CoP of the row and CoP% detected increased medial CoP deviation in FV ≥ 8°, and may be applied to other clinical conditions where rearfoot angle and CoP of the array after initial heel contact cannot detect significant differences.”

We will be talking about foot types this week on; Wednesday 8 EST, 7 CST, 6MST, 5 PST Biomechanics 314. Hope to see you there!

J Formos Med Assoc. 2015 May 5. pii: S0929-6646(15)00132-1. doi: 10.1016/j.jfma.2015.03.004. [Epub ahead of print]
Analysis of medial deviation of center of pressure after initial heel contact in forefoot varus.

picture from:

Some stuff you need to know about running spikes.

I see many track runners in my office, from middle school all the way into the USA Masters Division.  A few years ago one of the top USA Masters Milers came to see me on Friday before heading off to a national meet. He showed me some of his spikes (see pics above) and complained the there was something off on the spikes on the left, the Nike Mambas.  The shoe to the right is the Nike Zoom Miler.

You need to understand a bit of the physics of running turns to understand what is missing for this runner in this pair of spikes.  Things do change if you are running on a sloped track, but those are only found indoors and are not all that common to run on for most folks so we will stick with the thinking on flat tracks.

What you should be able to easily detect is that the Nike Mamba’s are missing the lateral 5th metatarsal forefoot spike on the cleat plate.  And you need to then realize that this is the right shoe, so it is the outside foot/leg on the track. It is the foot that will be pushing off harder from the outside on the turns to keep the centripetal forces of running a curve from allowing the runner to fall off the curve into the outer lanes. This right foot will always be pushing from outside to inside to maintain the body’s progression in the desired lane, when running the curves.

Think about it for a minute. In order to run in a circle, or a curve in this situation, the outside foot always has the tendancy to be more inverted to keep foot contact on the ground. This is where a Forefoot varus MIGHT come in handy ! This means the foot will be tipped to the outside a little, because of the curve and because the body will be leaning into the center of the track on the curves. Thus the foot and shoe will be relying on more lateral foot pressures to drive the body mass back into the lane since centripetal forces will always be driving you laterally out of the lane.  Thus, the lateral spikes on the right foot must be accommodating.  In the case of the Mamba shoe. there is only a sheet of black hard plastic over the midshaft-head of the 5th Metatarsal on the lateral foot. It is no wonder the runner was feeling like he was slipping on the turns (the front of the midfoot was not anchored to the ground, only the forefoot due to the spikes in that location). You can see clear evidence of the lateral slipping in the picture. Can you see the orange/brown patch where he was slipping ? A spike there in that area would have been wonderful.  Slipping is a power leak and a risk for injury.  If the foot is trying to gain purchase into/onto the track with the foot inverted there needs to be traction at that lateral foot, what is referred to as the Lateral Column.  You can see why the Nike Zoom Miler was a better choice, there is a nice spike placement under the lateral foot for just this measure, and there is no evidence of slippage wear.  He told me that the Mamba was a steeplechase designed shoe but we still both felt that the issue remained relevant even in that event. The Nike website however states that “the Nike Zoom Mamba Men’s Track and Field Shoe is perfect for the 800-5000m track athlete” so we think they have missed an issue here in our opinion.

I could make a better case for the Mambas if  they were for a 100m straight run but I would still like a 5th metatarsal /lateral spike where there isn’t one.  I will occasionally file spikes to get the perfect feel for the athlete.  It is usually the 5th metatarsal and 1st metatarsal spikes I mess with, merely to help hone the athletes feel on the track. The problem is that each track has a different feel so it is less of an occurrence in recent years.

It is good to know your shoes, it is good to know your physics. It is great to know them both and melt them together to solve problems.  Not all spikes are created equal, not all tracks are the same, not all events are the same and certainly not all feet and the athlete’s who own them are the same.  And on the topic of Forefoot Foot types, both the forefoot varus and forefoot valgus foot might have a problem with the Mamba’s depending on their strength, skill and strategies for ground purchase.  Hopefully your shoe store and your track and cross country coaches know these issues. You might want to bring this blog post to their attention however, just in case.

Dr. Shawn Allen


Here is an abstract you should look at.
Br J Sports Med. 2014 Mar;48(6):440-7. doi: 10.1136/bjsports-2013-092202. Epub 2013 Jun 13.

Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe: a 1-year prospective cohort study.

And then there is this article we came cross at Runner’s World online. Here is the article “Five things i learned about buying running shoes”.
In all fairness we do not think the article was meant to teach or say much, but we do feel like it robbed 2 minutes of our productive life, at least it was entertaining.
So it is our turn now, let us serve you some real meat.  Here are some loose thoughts on why shoe fit and research has limitations in our opinion, mostly commentary on the first article and why you need to takes its commentary with a grain of salt.
The problem lies in the knowledge base. Most researchers just do not seem to know enough about the foot types , osseous torsions, the kinetic chain, and the like, to do an ALL ENCOMPASSING study. Plus, such a study would be an infinite nightmare. This is where a clinician is needed, to draw upon all of the issues at hand, not just some of the issues.  
For example, in this study, they just looked at arch heights and their determination as to whether the foot was pronating to a degree  (foot-posture index and categorized into highly supinated (n=53), supinated (n=369), neutral (n=1292), pronated (n=122) or highly pronated (n=18).)
No where did they talk about foot types such as the very common forefoot variants of varus and valgus let along their compensated and uncompensated forms. No where were there discussions of tibial or femoral torsion or the possibly necessary foot pronation needs to bring the knee joint back to the sagittal plane. Plus, just because a foot is flat, doesn’t truly mean it is over pronated. It may be flat because of genetics, we have talked about genetic trends here in previous blog posts.  We see plenty of flat competent feet in our clinics. The may appear flat or over pronated , but that is not the case for many people. The FUNCTION must be examined, and this does not come from visual inspection or from gait analysis video. We always say “what you see in someones gait or foot function is often their compensation around other issues, it is not their problem”.
Shawn and Ivo, the gait guys

Did you see this in our recent blog post here ? a reader made us look closer. Did you catch it ?
The clients right foot appears to have a dropped 1st met head. (we hate this term, because it is not accurate and is a sloppy clinical description). In this still photo it appears plantarflexed.  But in this video, consider the descended 1st met head as due to the disuse or weakness of the EHL muscle (extensor hallucis longus) of the 1st toe. Or, is this in fact a compensated forefoot varus ? Sure looks like it. But with all that anterior compartment weakness (as we discussed in the previous blog post link above) it could just be a mirage. In the photo above, in a normal foot the rearfoot plane (greenline) should parallel the forefoot line (orange line). In this case, in this actively postured foot (thus some inaccuracy here, we are merely making a teaching point from the photo) the upslope of the orange line suggests a forefoot varus. This would be true if the first Metatarsal head also was on this line, but you can see that it has its own idea. This represents, in theory (regarding this photo), a compensated forefoot varus. But remember, this client is  holding the foot actively in this posture. A true hands on assessment is needed to truly define a Forefoot varus, and whether it is anatomic, flexible, rigid or in many cases, just a learned functional posturing from weakness of the flexor/extensor pairing of the 1st metatarsal complex or from other weaknesses of the other forefoot evertors.  It gets complicated as you can see.

As always, knowledge of the anatomy and functional anatomy allows for observation, and observation leads to understanding, which leads to answers and then remedy implementation. Our thoughts, knowing the case, is that this is a functional appearance illusion of a compensated forefoot varus due to the EHL, EDL and tibialis anterior weakness (anterior compartment) and how they play together with the flexors. One must be sure to assess the EHL when examining the foot. Test all of the muscles one by one.  We have been talking about toe extensors for a long time, they can be a paramount steering wheel for the forefoot and arch posture. Podcast 71 talks about this Forefoot varus, and you should care.
In a 2009 study by Reynard et al they concluded: 

  • “The activity of extensor digitorum longus muscle during the swing phase of gait is important to balance the foot in the frontal plane. The activation of that muscle should be included in rehabilitation programs.” (1)

here is the video again.

Have a burning desire to learn more about forefoot varus, here are 25 blog post links from our last few years. And/or you can take our National Shoe Fit program (downloadable links below).

Knowing what you are seeing during your exam and gait analysis can only truly come from coupling your observations with a clinical exam.  Anything less is speculation and guess work.  It is gambling, and this is not Vegas baby, this is someone’s health.

Shawn and Ivo, The Gait Guys


National Shoe Fit Certification Program:

Gait Guys online /download store (National Shoe Fit Certification and more !) :

1. Foot (Edinb). 2009 Jun;19(2):69-74. Epub 2008 Dec 31. Foot varus in stroke patients: muscular activity of extensor digitorum longus during the swing phase of gait.  Reynard F, Dériaz O, Bergeau J.

Other web based Gait Guys lectures:   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”Reference