Falling hard; Using supination to stop the drop.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand).  The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

This is a case that has been looked at before but today with new video. This is a client with a known anatomic short leg on the right (sock-less foot) from a diseased right hip joint.  

In this video, it is clear to see the subconscious brain attempting to lengthen the right leg by right foot strike laterally (in supination) in an attempt to keep the arch and talus as high as possible.  Supination should raise the arch and thus the resting height of the talus, which will functionally lengthen the leg.  This is great for the early stance phase of gait and help to normalize pelvis symmetry, however, it will certainly result in (as seen in this video) a sudden late stance phase pronation event as they move over to the medial foot for toe off. Pronation will occur abruptly and excessively, which can have its own set of biomechanical compensations all the way up the chain, from metatarsal stress responses and plantar fasciitis to hip rotational pathologies.  It will also result in a sudden plummet downwards back into the anatomic short leg as the functional lengthening strategy is aborted out of necessity to move forward.  

This is a case where use of a full length sole lift is imperative at all times. The closer you get to normalizing the functional length, the less you need to worry about controlling pronation with a controlling orthotic (controlling rate and extent of arch drop in many cases). Do not use a heel lift only in these cases, you can see this client is already rushing quickly into forefoot loading from the issues at hand, the last thing you should be doing is plantarflexing the foot-ankle and helping them get to the forefoot even faster !  This will cause toe hammering and gripping and set the client up for further risk to fat pat displacement, abnormal metatarsal loading, challenges to the lumbricals as well as imbalances in the harmony of the long and short flexors and extensors (ie. hammer toes). 

How much do you lift ?  Be patient, go little by little. Give time for adaptation. Gauge the amount on improved function, not trying to match the right and the left precisely, after all the two hips are not the same to begin with. So go with cleaner function over choosing matching equal leg lengths.  Give time for compensatory adaptation, it is going to take time.  

Finally, do not forget that these types of clients will always need therapy and retraining of normal ankle rocker and hip extension mechanics as well as lumbopelvic stability (because they will be most likely be dumping into anterior pelvic tilt and knee flexion during the sudden forefoot loading in the late midstance phase of gait). So ramp up those lower abdominals (especially on the right) !  

Oh, and do not forget that left arm swing will be all distorted since it pairs with this right limp challenge. Leave those therapeutic issues to the end, they will not change until they see more equal functional leg lengths. This is why we say never (ok, almost never) retrain arm swing until you know you have two closely symmetrical lower limbs. Otherwise you will be teaching them to compensate on an already faulty motor compensation. Remember, to get proper anti-phasic gait, or better put, to slow the tendency towards spinal protective phasic gait, you need the pelvic and shoulder “girdles” to cooperate. When you get it right, opposite arm and leg will swing together in same pendulum direction, and this will be matched and set up by an antiphasic gait.

One last thing, rushing to the right forefoot will force an early departure off that right limb during gait, which will have to be caught by the left quad to dampen the premature load on the left. They will also likely have a left frontal plane pelvis drift which will also have to be addressed at some point or concurrently. This could set up a cross over gait in some folks, so watch for that as well.

“One thing, affects all things. One change necessitates global change. The more you know, the more you will see (and understand).  The more you know, see and understand, the more responsible you will and should feel to get it right and the more global your approach should become. If your head does not spin at times with all the issues that need to be juggled, you are likely not seeing all the issues you should be seeing.” -Dr. Allen (from an upcoming CME course)

Shawn Allen, one of the gait guys.

The Rigid Flat Foot: Do you know what you are actually dealing with ?

In these 5 photos of a client with a flat arch we see some great opportunity to discuss some of the clinical issues and clinical thinking that needs to occur.  As usual we write our blog posts on the fly with a principle at hand that we want to drive home, or in this case “into the ground”.  There are many more clinical issues with this type of foot and its problems, so today’s list and dialogue is not meant to be exhaustive.  But, if you take one thing away from this case, it should be that not all flat feet can take a stability shoe or an orthotic. So, if you are in the mind set that “when it is flat, jack it up (the arch)” and “when it is high (the arch), cushion it” hopefully you will open your eyes a bit to the reality that it just is not that simple.  IF you want to learn more about these issues we have purposefully put together the National Shoe Fit program for stores and doctors/therapists so they can learn more about the anatomy of the feet and shoes and how to pair them up to create the best recipe for a person.  

Now, onto this case.

In this case you should notice a few things. 

1- the rigidity of the flat foot as portrayed in the photo where we are pushing up with our thumb on what once was the peak of the arch (yes, there are 5 photos in this case, click on one to enlarge or scroll) . We are attempting to push up, but the midfoot is completely rigid. This is a classic Rigid Flat Foot Deformity, A Rigid Pes Planus if you will. 

2- There is a prominence at the navicular bone, both top (dorsal) and bottom (plantar) aspects of the foot (see photo of my hand with finger and thumb indicating these areas). The plantar prominence is the actual naviular bone (mostly) that has become weight bearing (termed “weight bearing  navicular” and crudely by some as a dropped navicular, a term we dislike). And the dorsal prominence is a dorsal crown of osteophytes. This means a dorsal ridge of bone has formed at the navicular-1st cuneiform bone/joint interval because of the constant and repetitive compression of the two against each other dorsally as midfoot arch collapse occurred repeatedly and then became a fixed permanent entity.

3- The hyper dorsiflexion range at the 1st MTP joint (the big toe). This range is excessive at actually was able to exceed 90 degrees (see photo) !  Even at rest the hallux (big toe) is extended suggesting the volume of dorsiflexion it gets all the time.  By the way, there was little to no hallux 1st MPJ joint plantarflexion (downward bend), not in a foot this flat. In fact most of that is from the contracture of the short extensors of the toes as noted by the photo showing the hammer toe formation (hammer toe = contractured short extensor myotendon, and to the long flexors as well). Hammer toes are almost always seen in a flat foot presentation, to a degree.

Now, lets put some things together (but a reminder, this is a single principle today, there are many more issues here).

Today’s Principle: Passing the Buck

Normally we need to have just slightly greater than 90 degrees of ankle mortise dorsiflexion to progress the body over the ankle.  Put in other words, we need to be able to get the tibia slightly past vertical (perpendicular to the ground, hence 90+ degrees). Depending on the reference, anywhere from 15-25 degrees past that 90 degree vertical, thus 105 to 120 degrees) is the goal.

If an ankle cannot get that range, the range must be achieved either proximal or distal to that joint, ie. Passing the Buck beyond the ankle mortise joint.  Proximally, one can hyperextend the knee to enable the body mass to pass sagittally over the ankle but a better strategy (arguably) is to compensate distally via collapsing the arch and pronate more than normally through the midfoot putting undue stress and strain into the plantar fascia and over time eventually collapsing the arch and creating the dorsal and plantar bony prominences we mentioned in #2. By dropping the arch, the subtalar joint exceeds its ranges and the talus and navicular collapse medially and plantarwards. 
When the arch drops to the planus stage the tibia is passively thrust forward achieving the necessary forward tibial progression to get body over and past the ankle to enable forward progression. 
Remember, this pes planus will dorsiflex the long metatarsal bone (meaning make it parallel to the ground). This will screw up the 1st Metatarsal-phalangeal joint function and  impair the Windlass Mechanism of Hicks at the big toe (translation, it will impair the sesamoids, possibly leading to sesamoiditis, and change the normal toe function and its tendons.  This is seen both in the pes planus foot and in hallux rigidus turf toe presentations where the big toe loses its  normal ranges as compared to this case here).

So, the normal range can as for the buck to be passed proximally into the kinetic chain or distally. Which one would you want, if you had to chose?  It is a tough choice, luckily the body decides for us.  IF you consider that luck !
Regardless, one has to stand in awe that the body will find a way to get the range elsewhere when it cannot find it in the primary motor pattern.  And when the range has to be gained elsewhere, the muscular function has to change as well and prostitute the normal kinetic chain motor patterns. 
Here is a tougher question for you. Would you want this phenomenon on one side and be uniliaterally compromising (and thus have to compensate on the opposite side) the kinetic chain or bilaterally and have the asymmetry on both sides ?  That is a tough one. There is no good choice however.

*So, a flat RIGID foot.  If you jam an agressive orthotic (or possibly even a motion control shoe) under this foot it could very likely be painful to those rigid bony prominences and it will remove the client’s “passing the buck” compensation. Now the forces may have to revert to the proximal strategy at the knee.  So, when do YOU go with the orthotic or motion control shoe ? When it comes to the feet, use your head.  And, consider the Gait Guys, National Shoe Fit DVD program.  Email us at : thegaitguys@gmail.com

External Tibial Torsion as expressed during gait.

So, last week we watched this young lad doing some static ankle and knee bends, essentially some mini squats.  Here was what we found (LINK). It is IMPERATIVE that you watch this LINK first before watching today’s video above.

Now that you have watched that link here is what you should be seeing today.

You should see that the left foot is extremely turned out. We talked about why in the linked post from last week. It is because of the degree of external tibial torsion.  When it is present the knee rides inside the foot progression line (the knee bends into the forward / sagittal plane when the ankle bends into its more lateral /coronal / frontal plane (they all mean the same thing) ie. when the foot points outwards.

Remember, the knee has only one choice of motion, to hinge forward and backward. When the knee is asked to hinge in any other direction once the foot is locked to the ground there is torque placed upon the knee joint and thus shear forces.  Menisci do not like shear forces, nor does articular joint cartilage.

So, once again we see the rule of “you cannot beat the brain” playing out. The brain took the joint with the least amount of tolerance, the knee, and gave it the easy job.  The foot was asked to entertain another plane of motion as evidenced here in this video with significant increased foot progression angle. 

When the foot progression angle is increased but the knee still must follow the forward body progression (instead of following the foot direction) the motion through the foot will be directly through the medial longitudinal foot arch.  And as seen here, over time this arch will fail and collapse. 

Essentially this lad is hinging the ankle sagittally / forward through the subtalar and midtarsal joints, instead of through the ankle mortise joint where ankle hinging normally should occur.

This is a recipe for disaster. As you can see here.  You MUST also know and see here that there is an obvious limp down onto that left limb. It appears the left limb is shorter. And with this degree of external tibial torsion and the excessive degree of foot pronation, the limb will be shorter. You need to know that internal limb spin and pronation both functionally shorten the limb length.  This fella amongst other functional things is going to need a full length sole lift. We will start with 3mm rubber infused cork to do so. And let him accomodate to that to start.

We will attempt to correct as much foot tripod (anti-pronation) control as possible to help reduce leg shortness as well as to help reduce long term damage to the foot from this excessive pronation. We will also strengthen the left gluteus medius (it was very weak) to help him engage the frontal/lateral/coronal plane better. This may bring that foot in a little. But remember, the foot cannot come in so far that it drives the knee medially. Remember who is ruling the roost here !…… the knee.  It only has one free range, the hip and foot have 3 ! 

Shawn and Ivo

The Solitary Turned out Right foot in a Barefoot Runner: Part 2

Here is a perfect example why we sometimes cringe when someone comes into our office with pain or problems and wearing minimalist shoes or worse yet, claims to be a barefoot runner.  This is a perfect example of a client, whether they are in your shoe store or in a medical office, that needs to be convinced to remain in their more stable trainers until the problem is unwound. 

In this video it is plain for anyone to see that the right foot/lower limb is clearly externally rotated and pronating excessively when compared to the left side.  This could be from weakness of the gluteus medius, loss of internal rotation or one of several other biomechanical flaws (be sure to review Dec 15th blog post on these topics ). However, it could also be anatomic.  This could be from external tibial torsion or a torsion at the femur.  Regardless, it is likely creating a functional short leg on the right because when we pronate heavily like this, the height of the talus and arch drops further than normal, and in this case further than the other side.  However, one could argue the opposite, meaning that this person is pronating heavily on the right to shorten that leg to be equal to an already shorter left leg. In order to know, and not guess, you have to assess your client.  As indicated above, the internal limb spinning pronation could be a compensation to gain more entire limb internal rotation from a loss of hip rotation. Yes, there could be many causes. In this latter case, prescribing an orthotic to dampen this pronatory excess would be a mistake for the hip even though it would be a logical intervention at the foot level.  Our direction would be to find the cause of the right limb turn out and hyperpronation.  Video gait analysis and guessing will not get you there.  You have to assess your clients neuromuscular ability and deficits.  If one were to bet on impaired internal hip rotation, a fairly high probability bet, then how many internal rotators of the lower limb can you name immediately without looking them up ? You will need this info at the tips of your fingers in an exam if you are going to prove or disprove the internal hip rotation theory.  Here are a few to get you started:

  • vastus lateralis
  • TFL-ITB
  • anterior head of gluteus medius
  • reflected head of rectus femoris
  • adductor brevis
  • coccygeal division of gluteus maximus
  • how many others can you name and accurately test so that you are not guessing when it comes time to assess your client ?

Welcome to the complex game we play every day with our athletes and “every day Joe’s”. It is a brain knocking game, and  you have to juggle many factors while sorting it out. ! Tomorrow we will talk a little about possible problems of Functional Screens and how they can be used to help assess, but also how they can fool you.

Have a good Monday gang….. and watch for the rampant spreading plague of the turned out foot.  It is nationwide already !

Shawn and Ivo, The Gait Guys

Factors that adversely effect the natural history of the pronated foot.

“Risk Factors that may adversely modify the natural history of the pediatric pronated foot.”  Clin Podiatr Med Surg. 2000 Jul;17(3):397-417. Napolitano C, Walsh S, Mahoney L, McCrea J.Department of Orthopaedic Surgery, Loyola University Medical Center, Maywood, Illinois, USA.

This article is a nice follow up to the video post from yesterday. The article talks about the flexible and rigid flat foot.  In yesterday’s video example we are dealing with a flexible flat foot deformity.  When he was non-weightbearing (which wasn’t seen in the video) he formed an arch.  As you can see in the video upon weightbearing the arch disappears but you can see that with the correct patterning employed, he can find an arch.  This is what we term a flexible flat foot deformity.  These types of feet have potential if there is sufficient muscular ability and if hyperlaxity in the ligamentous system can be overcome by neuromuscular support. If not, an orthotic may need to be utilized and be assistive.  The rigid flat foot, is one that does not form a competent arch, ever.  These feet are what they are, flat.  But, keep in mind…… some genetics do render a competent flatter foot.  Some of the strongest feet we have seen are on very low arched people / runners.  So, flatter does not always mean weak, be careful.  What you see is not necessarily what you get, even a rusted out Ford Pinto might have a Ferrari engine in it……. you just don’t know by looking, you have to test the competency of the foot (another example, look at Arnold Palmer’s golf swing, it isn’t the prettiest swing by any means…… but you probably wouldn’t bet a penny against him even these days, if you get our drift.)

As the abstract says. “Normally developing infants have a flexible flatfoot and gradually develop a normal arch during the first decade of life.”  The key word is NORMALLY.   You must consider risk factors that may affect the foot in its overall development.  The risk factors include ligamentous laxity, obesity, rotational deformities, tibial influence, pathological tibia varum, equinus, presence of an os tibiale externum, and tarsal coalitions.

Again, this is a nice follow up to our video from yesterday and brings home some additional good points to cogitate over. We knew we had a flexible flat foot with potential.  Knowing what you are starting with it vital for your success in treating the problem, and vital in determining long term success. 

We are, The Gait Guys ………. and even a bit geeky in neurodevelopmental physiology. (Yes, we have no life.) 

Shawn and Ivo

___________________________________________________________________________

Abstract of the Journal Article……. the link to the article is at the top of the blog post if you wish to obtain the article for further study.

Here is their abstract:

“Flatfoot is one of the most common conditions seen in pediatric podiatry practice. There is no universally accepted definition for flatfoot. Flatfoot is a term used to describe a recognizable clinical deformity created by malalignment at several adjacent joints. Clinically, a flatfoot is one that has a low or absent longitudinal arch. Determining flexibility (physiologic) or rigidity (pathologic) is the first step in management. A flexible flat foot will have an arch that is present in open kinetic chain (off weight-bearing) and lost in closed kinetic chain (weight-bearing). A rigid flatfoot has loss of the longitudinal arch height in open and closed kinetic chain. According to Mosca, “The anatomic characteristics of a flatfoot are excessive eversion of the subtalar complex during weight-bearing with plantarflexion of the talus, plantarflexion of the calcaneus in relation to the tibia, a dorsiflexed and abducted navicular and a supinated forefoot.” Normally developing infants have a flexible flatfoot and gradually develop a normal arch during the first decade of life. When evaluating an infant for a pronated condition, the examiner must also consider other risk factors that may affect the foot in its overall development. These contributing factors will play a role in the development of a treatment plan. The risk factors include ligamentous laxity, obesity, rotational deformities, tibial influence, pathological tibia varum, equinus, presence of an os tibiale externum, and tarsal coalitions. The authors realize other less significant factors exist but are not as detrimental to the foot as the primary ones discussed in depth. The primary risk factors that affect the pronated foot have been outlined. The clinician should always examine for these conditions when presented with a child exhibiting pronatory changes. A thorough explanation to the parents as to the consequential effects of these risk factors and their effects on the pediatric pronated foot is paramount to providing an acceptable comprehensive treatment program. Children often are noncompliant with such treatments as stretching and orthotic maintenance. The support of the parents is crucial to maintaining an effective treatment program continued at home.”

Factors that adversely effect the natural history of the pronated foot.

“Risk Factors that may adversely modify the natural history of the pediatric pronated foot.”  Clin Podiatr Med Surg. 2000 Jul;17(3):397-417. Napolitano C, Walsh S, Mahoney L, McCrea J.Department of Orthopaedic Surgery, Loyola University Medical Center, Maywood, Illinois, USA. This article is a nice follow up to the video post from yesterday. The article talks about the flexible and rigid flat foot.  In yesterday’s video example we are dealing with a flexible flat foot deformity.  When he was non-weightbearing (which wasn’t seen in the video) he formed an arch.  As you can see in the video upon weightbearing the arch disappears but you can see that with the correct patterning employed, he can find an arch.  This is what we term a flexible flat foot deformity.  These types of feet have potential if there is sufficient muscular ability and if hyperlaxity in the ligamentous system can be overcome by neuromuscular support. If not, an orthotic may need to be utilized and be assistive.  The rigid flat foot, is one that does not form a competent arch, ever.  These feet are what they are, flat.  But, keep in mind…… some genetics do render a competent flatter foot.  Some of the strongest feet we have seen are on very low arched people / runners.  So, flatter does not always mean weak, be careful.  What you see is not necessarily what you get, even a rusted out Ford Pinto might have a Ferrari engine in it……. you just don’t know by looking, you have to test the competency of the foot (another example, look at Arnold Palmer’s golf swing, it isn’t the prettiest swing by any means…… but you probably wouldn’t bet a penny against him even these days, if you get our drift.) As the abstract says. “Normally developing infants have a flexible flatfoot and gradually develop a normal arch during the first decade of life.”  The key word is NORMALLY.   You must consider risk factors that may affect the foot in its overall development.  The risk factors include ligamentous laxity, obesity, rotational deformities, tibial influence, pathological tibia varum, equinus, presence of an os tibiale externum, and tarsal coalitions. Again, this is a nice follow up to our video from yesterday and brings home some additional good points to cogitate over. We knew we had a flexible flat foot with potential.  Knowing what you are starting with it vital for your success in treating the problem, and vital in determining long term success.  We are, The Gait Guys ………. and even a bit geeky in neurodevelopmental physiology. (Yes, we have no life.)  Shawn and Ivo ___________________________________________________________________________ Abstract of the Journal Article……. the link to the article is at the top of the blog post if you wish to obtain the article for further study. Here is their abstract: “Flatfoot is one of the most common conditions seen in pediatric podiatry practice. There is no universally accepted definition for flatfoot. Flatfoot is a term used to describe a recognizable clinical deformity created by malalignment at several adjacent joints. Clinically, a flatfoot is one that has a low or absent longitudinal arch. Determining flexibility (physiologic) or rigidity (pathologic) is the first step in management. A flexible flat foot will have an arch that is present in open kinetic chain (off weight-bearing) and lost in closed kinetic chain (weight-bearing). A rigid flatfoot has loss of the longitudinal arch height in open and closed kinetic chain. According to Mosca, “The anatomic characteristics of a flatfoot are excessive eversion of the subtalar complex during weight-bearing with plantarflexion of the talus, plantarflexion of the calcaneus in relation to the tibia, a dorsiflexed and abducted navicular and a supinated forefoot.” Normally developing infants have a flexible flatfoot and gradually develop a normal arch during the first decade of life. When evaluating an infant for a pronated condition, the examiner must also consider other risk factors that may affect the foot in its overall development. These contributing factors will play a role in the development of a treatment plan. The risk factors include ligamentous laxity, obesity, rotational deformities, tibial influence, pathological tibia varum, equinus, presence of an os tibiale externum, and tarsal coalitions. The authors realize other less significant factors exist but are not as detrimental to the foot as the primary ones discussed in depth. The primary risk factors that affect the pronated foot have been outlined. The clinician should always examine for these conditions when presented with a child exhibiting pronatory changes. A thorough explanation to the parents as to the consequential effects of these risk factors and their effects on the pediatric pronated foot is paramount to providing an acceptable comprehensive treatment program. Children often are noncompliant with such treatments as stretching and orthotic maintenance. The support of the parents is crucial to maintaining an effective treatment program continued at home.”

Factors that adversely effect the natural history of the pronated foot.

The Risks for Forefoot Strike running. YOU NEED TO READ THIS ! YES, YOU !

OK, we are going to go on a rant here…… it is time.

We have been talking about problems of forefoot strike for some time now. We like a midfoot strike, and we have research-based, well founded logic to our opinion.  A Forefoot strike reduces the amount of pronation possible for shock absorption because  when the foot is plantarflexed it is in a supinated state which is reserved for a rigid propulsive mechanism.  At impact some degree of pronation is necessary otherwise force attenuation must occur elsewhere in the kinetic chain otherwise it creates bone, joint or soft tissue pathology/injury somewhere in the chain.  However, one of the major issues we have been pounding our fists on the table about, for years, are forefoot orientation anomalies.  A significant portion of the population have forefoot types of varus or valgus, some flexible and some more rigid, some compensated and some uncompenated (yes, this is difficult stuff……but if you are going to make orthotics or if you are going to be a runner or sell or make shoes or coach or even speak about running form styles…… you had better know this stuff or we will call you out on it). 

No one is talking about this stuff except The Gait Guys. 

Is this because no one knows about it ? Maybe.

It is because those in the running fields do not understand it well ? Likely. 

It is because it creates fear and anxiety about selling shoes ? Probably.

Is it because it complicates shoe fabrication? Likely. 

Does that make it right to just ignore it all together ? No ! 

With a forefoot strike into one of these “pathologic” forefoot types the anatomical variance is accentuated.  In this scenario, a varus foot type that lands and subsequently has not choice but to drive hyperpronation strain not only suffers from the increased pronatory collapse but they are unable to acquire a subsequent rigid toe off which in itself can drive further pathology.  And a valgus forefoot strike is even more rigid than a neutral forefoot strike impact and they are also at risk for inversion strain on the lateral foot.  A midfoot strike can reduce some of these consequences by setting the foot up for a preparatory transition. We know this, we see this everyday, it is what we do. These runners need to be categorized and educated as to why their injury is present or chronically persists, and why we insist a program to reteach a midfoot strike. 

As always, if the doctor knows what anatomy presents itself with the client, and adequately educates the athlete……..then a good relationship and outcome will ensue. Additionally, a change in shoe is not  uncommon when their strike mechanics change.

Here is what spurred our soapbox rant today…….. thanks Lower Extremity Review for bringing the June ASCM to light early !!!
_________________________________________________________________________________

from LER, Link is above:

“The frequency content of vertical ground reaction forces generated during running differ among forefoot strikers and rearfoot strikers, and this may have implications for injury risk, according to findings from the University of Massachusetts presented in June at the ACSM meeting.

Researchers assessed frequency amplitude and power in 10 natural rearfoot strikers and 10 natural forefoot strikers as they ran across a force platform.

At frequencies above 9 Hz, rearfoot strikers’ amplitude exceeded that of forefoot strikers. Similarly, above 22 Hz, power was significantly greater in rearfoot strikers. This is consistent with previous reports that only rearfoot strikers have an impact peak, which occurs between 10 Hz and 20 Hz.

But between 4 Hz and 7 Hz, amplitudes were higher in forefoot strikers. And for frequencies less than 6 Hz and between 9 Hz and 11 Hz, power was greater in forefoot strikers.

Because the body attenuates shock differently at different frequencies, the findings could suggest that even forefoot strikers (including most barefoot runners) may be at risk for certain injuries despite lacking an impact peak.”

The Risks for Forefoot Strike running. YOU NEED TO READ THIS ! YES, YOU !