Inverted ? Cross over gait? How we do all things ?

How we do one thing, is how we do all things.

I was sitting having my morning coffee earlier than normal this morning, which left me time to ponder some things.
Look at this picture, is this not a magnification of the "cross over gait" x100 ? Thus, is that planted foot not inverted ? Yes, it has to be, to a degree, a high degree. There is a reason why soccer players have a great affinity for ankle sprains.
When we have a narrow based gait, we are most likely going to strike more laterally on the foot, more supinated, if you will. If you widen step width, less inversion, less lateral forces (typically) and less supination (typically) compared to a narrow based gait. 
If we descend stairs with our feet in a more narrow based gait, we are not only going to be inverted more, but striking at the ball of the foot, thus, more on the lateral foot tripod. This is the typical inversion sprain injury position. 
When we jump, we should be trying to land with our feet more abducted, certainly not narrow based, because if we are too narrow we are at more risk for the same lateral forefoot landing and thus ankle inversion event. Just like descending stairs.

We see plenty of ankle inversion events. Why? 
Because most people do not have enough hip abduction or peroneal skill, strength, endurance and they are unaware of their weak gait patterns or their ankle spatial awareness. Many have lazy narrow based gaits and insufficient proprioceptive awareness. And, they carry these things over into running, walking, jump landing (ie. volleyball, basketball, etc), and descending stairs, just to name a few.

How we do one thing, is how we do all things (mostly).

-Dr. Allen

Addendum:

Rickie Lovell : As he struck the ball it would been everted. The momentum of the follow through will have off loaded the everted foot as the energy moves in a similar line to that of the ball. It is extremely rare for a footballer to get a sprain from this, I certainly didn't see over several years working in professional football. 
On a side note, find some footage of David Beckham taking free kicks - the mechanics are astounding!

The Gait Guys: possibly everted, but no guarantee.It still looks pretty inverted to me.But we see your point, and is a real good one, real good. Super good. We will check our the bender-man thanks for chiming in with such great insight !

The Gait Guys:  yes, the momentum of the leg kicking across the body would externally spin the stance leg. The picture is likely showing the offloading phase, not the loading. Bueno !

Can you see the problem in this runner’s gait ?

You should be able see that they are heel impacting heavy on the outside of the rear foot, and that they are doing so far laterally, more than what is considered normal.  

This is a video of someone with a rear foot varus deformity.

These folks typically have a high arched foot, typically more rigid than flexible, and they are often paired with a forefoot valgus.  

Q: Do you think it might be important as a shoe fitter to know this foot type ?

A: Yes

Q.Should they be put in a shoe with a soft lateral crash zone at the heel ? 

A: No, absolutely not. Why would you want to keep this person deeper and more entrenched on the lateral heel/foot ?!

This foot type has a difficult time progressing off of the lateral foot. The lateral strike pattern and the tendency for the varus rear-foot (inverted)  keeps this person on the lateral aspect of the foot long into midstance.  This eats up time when they should be gradually progressing over to the medial forefoot so that they can get to an effective and efficient medial (big toe) toe off.  This gait type is typically apropulsive, they are not big speed demons and short bursts of acceleration are difficult for these folks much of the time. Combine this person with some torsional issues in  the tibia or femur and you have problems to deal with, including probably challenges for the glutes and patellar tracking dysfunction. What to see some hard, tight IT Bands ?These folks are often the poster child for it. Good luck foam rolling with these clients, they will hate you for recommending it !

They are typically poor pronators so they do not accommodate to uneven terrain well.  Because they are more on the outside of the foot, they may have a greater incidence or risk for inversion sprains. You may choose to add the exercise we presented on Monday (link  here) to help them as best as possible train some improved strength, awareness and motor patterns into their system. In some cases, but only when appropriate, a rear foot post can be used to help them progress more efficiently and safely. 

These foot types typically have dysfunction of the peronei (amongst other things). A weak peroneus longus can lead to a more dorsiflexed first metatarsal compromising the medial foot tripod stability and efficiency during propulsion while also risking compromise to the first metatarsaophalangeal (1st MTP) joint and thus hallux complications.  Additionally, a weak peroneus brevis can enable the rear foot to remain more varus. This muscle helps to invert the rearfoot and subtalar joints. This weakness can play out at terminal swing because the rear foot will not be brought into a more neutral posture prior to the moment of heel/foot strike (it will be left more varus) and then it can also impair mid-to-late midstance when it fires to help evert the lateral column of the foot helping to force the foot roll through to the big toe propulsive phase of terminal stance.  (* children who have these peroneal issues left unaddressed into skeletal maturity are more likely to have these rearfoot varus problems develop into anatomic fixed issues…… form follows function.)

You can see in the video the failed attempt to become propulsive. The client speeds over to the medial foot/big toe at the very last minute but it is largely too late. Sudden and all out pronation at the last minute is also fraught with biomechanical complications.

One must know their foot types. If you do not know what it is you are seeing, AND know how to confirm it on examination you will not get your client in the right shoe or give them the right homework.

* caveat: the mention of Monday’s exercise for this foot type for everyone with Rearfoot varus is not a treatment recommendation for everyone with the foot type. For some people this is the WRONG exercise or it might need modifications. Every case is different. The biomechanics all the way up need to be considered. Medicine is not a compartmentalized art or science. 

Shawn and Ivo, The Gait Guys

Oval Track Running Injuries, Part 2. The Details.

Last week we did a blog post on the problems that oval track running can set up in terms of injury and promoting asymmetry, LINK).  We wanted to briefly go back to that article to hit some details that many folks did not put together. 

Keep in mind as you read on that the scenario is the typical counterclockwise oval track running.  As it said in the study, “analysis indicated that the left (inside limb) invertors increased in strength significantly more than the right (outside limb) invertors while the right evertors increased in strength significantly more than the left evertors.”

What this means is that someone who runs repeatedly counterclockwise on an oval track will drive skill, endurance and strength (the 3 basic tenets to solidifying a motor pattern) into the inside limb invertor muscles. This means the tibialis posterior, medial gastrocsoleus complex, flexor hallucis longus (likely) as well as some of the medial foot intrinsics. Because they are invertors, they are fighting the pronatory eversion forces on the track surface. These muscles will help to keep the ankle and foot neutral and slow the rate of foot pronation.  When these muscles are weak we see posterior shin splints in the left foot/ankle early in the track season. 

Whereas, the outside limb will be staving off the forces that want to launch the person off of the curves and off the outside of the track. Hence this limb will constantly redirect the forces inwards into the center of the track so that centripetal forces can continue to act to keep the runner on the curve (centripetal force is defined as a force which keeps a body moving with a uniform speed along a circular path and is directed along the radius towards the center). This means that the evertor muscles of the outside leg will be gaining skill, endurance and strength with every lap of training.  Hence, improvements in the peroneal group, the lateral gastrocsoleus namely.  Without these improvements the outside ankle would eventually fail and the forces are synonymous with inversion sprain mechanics.  Remember, here as well, these improvements in these muscle groups are designed to try and hold the ankle in a safe neutral biomechanical position and avoid inversion injury via the imparted forces.

It is also imperative to point out that the inside foot will see more ankle (mortise) dorsiflexion and eversion and the outside ankle will be seeing more (mortise) dorsiflexion and inversion.  We know that there are two heads to the tibialis anterior, one helps create more eversion and one more inversion.  Do we also want to see an imbalance and experience differential there as well ? If you have been with The Gait Guys for the last 4 years you will know that we harp on symmetrical ankle rocker range and function.  How can we expect to stay injury free with all this purposely driven asymmetrical skill, endurance and strength ?

Then one must remember that these muscular chains do not stop locally. If the inside foot invertor muscles are strengthened it is likely that the tonus and capabilities of the inner leg chain will be improved upon let alone the spiral chains as well.  Inner thigh groups including the adductors improve lower abdominal function from what we see in decades of clients. But remember, the outside leg is not seeing this same chain of muscles getting ramped up, rather it is seeing the lateral chain higher up improving which included the right gluteus medius to name just one. Furthermore, and we have talked about this until blue in the face, when  you have asymmetrical lower limb function you have asymmetrical upper limb swing.  We see shoulder and neck imbalances in our track athletes all the time.  And, then think about this, on non-track days what to many track athletes do ? They then go and drive massive strength into these asymmetries by going into the weight room and drive the problem deeper.

Our point here is that we are driving massive asymmetry into the human track machine. As as with any machine, loosen one bolt on one side and tighten the same bold on the other side and there will be a price to pay in the function of the machine. In the short term it will be one of performance, in the slightly longer term it will be one of injury.  As this study suggested, “ a high incidence of lower extremity injury (68%) occurred in this sample of runners, corresponding to an injury rate of 0.75 injuries per 100 person-hours of sport exposure. Although sample size was limited, secondary analysis indicated that strength changes were not significantly different for injured (n = 17) and uninjured (n = 8) runners (p > 0.05)”. Our response to the later statement is “give it time!”.  If you are one of these track athletes and are not injured, we like to say that you are likely lucky……. for now.

If you are a coach or an athlete, for the sake of your feet and legs……. use your head.

Shawn & Ivo

details, details, details……… because details matter.

______________________

Clin J Sport Med. 2000 Oct;10(4):245-50.

Asymmetrical strength changes and injuries in athletes training on a small radius curve indoor track.

Beukeboom C, Birmingham TB, Forwell L, Ohrling D.

Abstract

OBJECTIVES:

1) To evaluate strength changes in the hindfoot invertor and evertor muscle groups of athletes training and competing primarily in the counterclockwise direction on an indoor, unbanked track, and 2) to observe injuries occurring in these same runners over the course of an indoor season.

DESIGN:

Prospective observational study.

SETTING:

Fowler-Kennedy Sport Medicine Clinic, The University of Western Ontario, London, Ontario.

PARTICIPANTS:

A convenience sample of 25 intercollegiate, long sprinters (200-600 m) and middle distance runners (800-3,000 m) competing and training with the 1995-1996 University of Western Ontario Track and Field team.

MAIN OUTCOME MEASURES:

A standardized protocol using the Cybex 6000 isokinetic dynamometer was used to measure peak torques of the hindfoot invertor and evertor muscle groups of both limbs using concentric and eccentric contractions performed at angular velocities of 60, 120, and 300 degrees/sec. Changes in peak torques between the preseason and postseason values were calculated and compared using a repeated measures analysis of variance test. Injury reports were collected by student athletic trainers and in the Sport Medicine and Physiotherapy clinic.

RESULTS:

Primary analysis indicated that the left (inside limb) invertors increased in strength significantly more than the right (outside limb) invertors (p = 0.01), while the right evertors increased in strength significantly more than the left evertors (p = 0.04). A high incidence of lower extremity injury (68%) occurred in this sample of runners, corresponding to an injury rate of 0.75 injuries per 100 person-hours of sport exposure. Although sample size was limited, secondary analysis indicated that strength changes were not significantly different for injured (n = 17) and uninjured (n = 8) runners (p > 0.05).

CONCLUSIONS:

The observed small, but statistically significant, asymmetrical changes in strength of the hindfoot invertor and evertor muscle groups can best be described as a training effect. Altered biomechanics proposed to occur in the stance foot while running on the curve of the track are discussed in relation to the observed strength imbalance. A causal link between strength changes and lower extremity injuries cannot be inferred from this study, but suggestions for further research are made.

Injures induced by running the same direction on an indoor/outdoor track.

We have been seeing, addressing and treating this problem for years, far too many years. There are few things that frustrate us more than coaches and athletes who refuse to alternate their track workouts into the clockwise direction to help avoid the repetitious detrimental training effects of continued and repeated counterclockwise track training. 

Here is a study from 2000 that tends to validate a causal link to our point. The study confirms a statistically significant asymmetrical strength development in the hindfoot invertor and evertor muscle groups. 

Imbalances are a frequent and well known cause of injury.  Consciously driving this asymmetry is the equivalent to purposefully encouraging injury if you as us.  Why anyone would not heed recommendations to balance out workout effects is beyond us.  We encourage road work so that there are no repetitive track banks to negotiate and thus knowingly drive asymmetry.  When weather makes outdoor work an impossibility then days should ideally alternate the flow on the track to counter the direction of the previous day.  And as track event days get closer then the inevitable will occur that you want to simulate race day direction but at least deeply engrained (skill, endurance and strength) training effects in the counterclockwise direction will not terribly risk injury as much as if there had been no training changes and accommodations.

The smaller the track radius the more detrimental the training effects. Frequency and duration of the training further magnifies training effects. A banked track will mute some of the effects but not all of them. 
So why not just reverse the direction of your track training ?  And don’t tell is it is logistically too difficult to coordinate, that is a lame excuse. You are training yourself or your athletes to be better runners, so you should want to reduce risks and optimize training effects. Period.

Shawn and Ivo……… The Gait Guys

Clin J Sport Med. 2000 Oct;10(4):245-50.

Asymmetrical strength changes and injuries in athletes training on a small radius curve indoor track.

Beukeboom C, Birmingham TB, Forwell L, Ohrling D.

Abstract

OBJECTIVES:

1) To evaluate strength changes in the hindfoot invertor and evertor muscle groups of athletes training and competing primarily in the counterclockwise direction on an indoor, unbanked track, and 2) to observe injuries occurring in these same runners over the course of an indoor season.

DESIGN:

Prospective observational study.

SETTING:

Fowler-Kennedy Sport Medicine Clinic, The University of Western Ontario, London, Ontario.

PARTICIPANTS:

A convenience sample of 25 intercollegiate, long sprinters (200-600 m) and middle distance runners (800-3,000 m) competing and training with the 1995-1996 University of Western Ontario Track and Field team.

MAIN OUTCOME MEASURES:

A standardized protocol using the Cybex 6000 isokinetic dynamometer was used to measure peak torques of the hindfoot invertor and evertor muscle groups of both limbs using concentric and eccentric contractions performed at angular velocities of 60, 120, and 300 degrees/sec. Changes in peak torques between the preseason and postseason values were calculated and compared using a repeated measures analysis of variance test. Injury reports were collected by student athletic trainers and in the Sport Medicine and Physiotherapy clinic.

RESULTS:

Primary analysis indicated that the left (inside limb) invertors increased in strength significantly more than the right (outside limb) invertors (p = 0.01), while the right evertors increased in strength significantly more than the left evertors (p = 0.04). A high incidence of lower extremity injury (68%) occurred in this sample of runners, corresponding to an injury rate of 0.75 injuries per 100 person-hours of sport exposure. Although sample size was limited, secondary analysis indicated that strength changes were not significantly different for injured (n = 17) and uninjured (n = 8) runners (p > 0.05).

CONCLUSIONS:

The observed small, but statistically significant, asymmetrical changes in strength of the hindfoot invertor and evertor muscle groups can best be described as a training effect. Altered biomechanics proposed to occur in the stance foot while running on the curve of the track are discussed in relation to the observed strength imbalance. A causal link between strength changes and lower extremity injuries cannot be inferred from this study, but suggestions for further research are made.

Do you think I need to replace my shoes?

These shoes appear to be well past their prime, to say the very least ! These poor dogs have the rear and forefoot varus “worn” right into them. You can see this represented particularly easily from the front, look at the lateral sloping of the shoe. It almost appears as if his foot could slide off the outside edge of the shoe. One can easily postulate that an inversion ankle sprain is just one unfortunate step away.

It looks like this medially posted shoe is not working for this fellow (you can see the medial post on the inner edge of the EVA midsole if you look carefully)  If you have questions on the “flare”?/post click here) . The client told us that they are “only a few years old” and planned on running one more ½ marathon in them this spring! Of course we mentioned they should put a office visit on the books the day after that race, because their ankles and knees were likely going to need it !

One can only imagine the lateral (genu varum) forces being placed on the knees, and who knows what kinds of increased shear forces are imparted into the menisci.  The lateral (inversion / varus) forces are going to impart a tendency of external rotation into the hips, and if one is busy externally rotating they are not going to internally rotate the hips when it is necessary to as the pelvis passes over the foot in midstance.  Additionally, an inverted /varus postured foot is more rigid because it is supinated which makes for a poor pronation/shock absorbing foot during the accomodative phase of the stance phase.

There are many more issues we could discuss here. But this was never meant to turn into a diatribe on specific biomechanical flaws, not this time at least.  Just remember this, whatever biomechanical flaws your feet have (and most of us have them) will eventually be pressed into the EVA foam of your shoes. Meaning, in time your shoes will reflect your aberrant flaws biomechanically.  And these newly built-into-the-shoe problems will now magnify the foot’s challenges and can accelerate pathology locally and globally.  Change your shoes often and as we have suggested in older blog posts, please consider having 2 shoes in your regular rotation.  One shoe being older and one being newer. We suggest starting an new shoe into the rotation once the old shoe has 200-250 miles and then alternating shoes every other day.  This way the foot is never seeing an older more deformed shoe for more than a day before getting some correction.  The point here, don’t let a shoe get 400-500 miles on it, in all its deformed glory, and then suddenly force the foot into a sudden biomechanical correction with a brand new shoe.  Abrupt changes lead to abrupt biomechanical demands on the system, so limit them and limit your risk for injury.

PS: Note the nice after-market “venting feature” in the right shoe near the little toe.

What some folks will try to do to save a few bucks…

Ivo and Shawn, The Gait Guys