Running Strong: Video Analysis, Running Re-education and Strength and Power Program for Runners

The Running

Strong Program

What is it?

A 4 session program to improve your running and decrease your chance of injury.

What is it composed of?

  • Detailed analysis of your running history and programming to find predictors of injury
  • High Speed Camera (240 frames/second) analysis of your running form
  • Pelvic Drop
  • Detailed functional evaluation of your physical function designed to find weak links
  • Custom created corrective exercise and performance based exercise program including 3 follow up sessions

Is it covered by insurance?

 

Yes.  I am both a physiotherapist and chiropractor.  Each session can be billed separately and our rates are well within the normal fees charged for regular physiotherapy sessions

The cost?

$400.00 for the initial 1 hour session plus 3 follow up sessions.

The timeframe?

The timeframe is surprisingly flexible.  Some people need a follow up session within a week of the initial evaluation.  Others might need a follow-up session within 3 weeks.  Having this flexible time frame allows us to tailor the program to your needs.

Can I work with my existing coach or personal trainer?

Absolutely.  In fact, this is encouraged.  I regularly work with running or triathlon coaches to create safer and better training programs.  If you already work with a personal trainer we can speak with your trainer about encorporating the running performance program into your existing exercise sessions.

About Me:

I am physiotherapist and chiropractor with a MSc in Exercise/Spine Biomechanics.  I have published more than 20 peer-reviewed academic papers on exercise science and injury.  I regular work with runners and multisport athletes from beginner's to Olympic athletes.  I currently write injury prevention articles for Triathlon Canada.  I am also an instructor with therunningclinic.ca - Canada's, if not the World's, leading course on the prevention and treatment of running injuries.  Last, I am the clinical director of Medcan's Run Well 3D Kinematic Analysis Program for Running Injuries.

Related Posts

1. Running Strength: Moving beyond the Core

2. Running Biomechanics: Clinical decision making in running analyses

3. Gait Modifications for Runners.

 

Form, footwear and footstrike: an e-book on running mechanics review with injury insights

This post is a link to a pdf ebook on the presentation I gave for the MSK-Plus course November 25, 2012.  Below I give a brief intro into the confusion that surrounds these topics.  If you note a huge amount of uncertainty, a whiff of grey and lack of simple answers than your interpretation is correct.

 

The pdf file is form footwear and footstrike running mechanics ebook nov20 2 2012.

Related posts

1. Barefoot running and footstrike style overview

2. Gait modifications to influence impact loading

3. Barefoot running and running economy

4. Running in the backseat: lack of hip extension and its possible relationship to injury

5. What we know and don't know about running injury prevention

Overview

We can change the following variables of running:

1. Kinematics or changing the position of the body (e.g. trying to not let your knees collapse inwards) or the timing of events (e.g number of strides per minute)

2. Footstrike style

3. Footwear: barefoot, "barefoot shoes", minimal shoes, traditional cushioned shoes with an attempt to "correct" something

We also hope that changes in mechanics will occur.  Some variables that may be related to injury:

1. Rate of impact loading

2. Joint forces

3. Muscle loading, timing or activation levels

4. Joint kinematics

 

We assume that making one change will result in positive changes in other variables. The big assumption is that we know what is bad in running.  It sounds so simple, but in practice it is not. Especially when we deal with something like pain and injury.

What you will see in the attached e book is that nothing is that simple.  Changes in many variables related to running often don't result in the "positive change" in some running variable that we hope for.

 

Below is a brief introduction to the modifiable variables and their relationship to running mechanics and to a less extent injury.  The attached pdf file goes into a little more detail.

 

Modifiable variables during running

Run barefoot or run minimal

I wish it were this simple.  We have some data suggesting that some barefoot runners will run with a forefoot strike, reduced stride length and other changes and thus they will have a decreased rate of impact loading.  We have no data suggesting that making this change reduces injury and the link between rate of impact loading and injury is a wee bit murky.  We also have a number of research studies showing that just changing to barefoot is not sufficient to result in decreases in the rate of impact loading.

In Lehman's terms, we may want to be cautious about any blanket statements

 

Lose the cushioned shoes and run in flats

I do this but I certainly don't think its the answer for everyone. I also run in cushioned shoes because I think variety is important.  As for mechanical changes when going to flats there is not a lot of robust data out there that supports this in terms of biomechanics.  The assumption is that if you lose the heel on your shoes and the cushion you will automatically start to run with a softer gait.  Again, this is not supported in the literature and research exists showing increases in rate of loading and joint loading with racing flat like shoes.  Again, we need to reserve our blanket statements.

 

Convert from a heel strike to a forefoot or midfoot

The assumption is that heel striking is bad.  Again, not strongly supported in the literature.  Research is mixed with some work showing decreases in the rate of impact loading when going to midfoot or forefoot but we also have conflicting work showing the opposite.  Again, blanket statements are not cool.  The epidemiological research is also in its infancy, is correlational in nature and correlation data sucks for implying causation.

Decreasing stride length and increasing stride rate

This modification may have the most support and may be a common variable in other interventions.  For example, I think that someone might strike the ground with a forefoot strike and have a large rate of impact loading if they have a long stride, while another individual might convert to a forefoot strike and also decrease the length of their stride.  We might initially conclude that the forefoot strike was the variable that resulted in the decrease in the rate of impact loading but really it was just having a shorter stride.  This may also be a factor with barefoot interventions.  Barefooters tend to stride shorter...maybe those barefooters with higher impact loading rates failed to decrease their stride length.  BUT, and there is always a but, we do have a well designed study that showed no changes in impact loading when increasing stride rate (Giandolini 2012).  I am not even sure how that is possible but that was their finding.

 

Kinematic variables

The ebook does not touch on this but these would be things like increased frontal plane projection angle, hip valgus, hip internal rotation, pelvic obliquity, lack of hip extension, increased anterior pelvic tilt, prolonged pronation, lack of pronation, uneven arm swing, lack of trunk rotation etc.  Surprisingly, we have very mixed data on this.  Even the biggies like increased hip internal rotation and hip valgus.  Sure there is some correlational data that shows that some runners with knee pain have greater amounts of hip valgus when compared with controls but the predictive data is much weaker.  We also have data showing no relationship between assumed gait flaws and any current injury.

We don't know if pain begets gait flaws (e.g hip weakness) or if the biomechanical flaw caused the pain.  What might surprise you is that we can often rehab a patient, get them running injury and painfree and they still present with the initial "biomechanical flaw".  My concern with assuming that some biomechanical variables are faulty is that this views the body as being inherently weak and we forget about its amazing variability and strength.  You will see lots of runners with huge amounts of hip valgus/knee collapse.  You will shudder in horror at this.  But sometimes that is just that person's little idiosyncrasy .  They have always done it and they have adapted.  You will try to fix them under the assumption that they are faulty.  But this a massive assumption.

I am working on a large post on the kinematics of gait and injury.  I will go into a lot of detail on this topic

 

OK.  So everything is grey.  What do I do?

 Warning: Opinions ahead.

Gait modifications can help with an individual in pain:  We have good data that a slow return to running with modifications to form can help.  I don't necessarily believe that this is always related to biomechanics in the sense that we are changing mechanics to be closer to an ideal.  I think we are changing mechanics and it is the act of change that is important.  Variability and novelty is important to me in all my rehab programs.  Changing your gait loads the body differently and is also different for the brain.  Different gait patterns may avoid certain physical stressors on the body and may not activate our pain neurotags because of the novelty.  Further, most gait re-training is a slow, gradual return to running.  This exploits our innate adaptive abilities.

 

How should people run if not in pain?

Please note, the suggestions below only relate to running form.  There are a lot of things we can do to reduce the risk of injury.  Below is not comprehensive.

If I have to go out on limb I would suggest four things:

1. Novelty and variety: different shoes, different surfaces, different speeds, different distances.

2. Check your cadence: if you are running a five minute kilometer than  your steps per minute should be greater than 170 per minute.  If  you are "loping" and don't have a quick turnover consider increasing your cadence.  What you are trying to avoid is landing with the foot extremely far in front of the body and this is associated with a close to straight knee at footstrike

3.   With reservation and many exceptions, a midfoot to forefoot strike with the occasional heel strike thrown in:  this one is tough for me to say and I have some hesitancy. If you are novice runner I would probably suggest running with a midfoot strike. I think the bulk of the research suggests that running with a midfoot strike is the way to go.  I know that there is research suggesting heel striking is fine especially if it is not associated with overstriding.  I totally get this.   As  I said, I have some hesitancy - I treat a lot of heelstriking runners and would not consider changing their gait so this suggestion is obviously not a blanket for everyone.  Many heelstrikers have their feet land close to their body and their gait is soft and quick. However,  I also think that thinking about midfoot striking will also help with your cadence.  Last, for slower runners (10 minute miles) I doubt footstrike matters as much.  One caveat, I also think many runners would benefit from using different footstrikes during the same run provided their cadence is not too low.  This is consistent with my views on variety.

4. Gradual increase in running or in changes in form.  This one is obvious.  The body adapts over time we just have to give it some time to adapt.

 

My bottom line

I would be hesitant to change things about someone's form if they have no injury or past history.  If they have had a series of past injuries or currently have an injury this is where I think we can help the most with changes in form.  What you will see in the e-book is that there are so many exceptions to our commonly held beliefs about certain running related variables.  These exceptions make me quite cautious in just trying to change runner's form when you don't actually know what you are causing when you try to make a change.  I am lucky in that I have access to 3D motion capture equipment.  I can see what happens with different changes in form.  But I don't have force plates and I can make no comment on changes in joint loading or impact loading.  And the "running expert physio" dude with one camera (or who just eyeballs a runner from behind) can't say what changes in force (e.g rate of impact loading are occurring) and is also probably wrong about a runner's kinematics should be a little cautious in just making changes based on one or two cherry picked research papers.  What the research in this e-book shows is that many changes we assume to be good end up resulting in elevated levels of impact loading or joint loading.  Thus, I advise caution.

 
 
 
 

 

 

 

Basic Runner's Strength Training: Program One

deadlift-down.jpg
deadlift down
deadlift down

Audience: Runner's looking to start a simple resistance exercise program who still want most of their time spent running Background

You can justify strength training for runners via performance enhancement and injury prevention.  Surprisingly, the evidence for performance enhancement is much stronger than injury prevention.

Components of a Good Strength Training Program

You can do thousands of different training programs.  Don't let someone tell you they have the best one or there is one best exercise for you.  I recommend that all good programs build comprehensive capacity.  Meaning you want a program that trains everything (or close to it)...you don't want to neglect a movement, a body part or some function (e.g. speed, power, strength) in a year round program.  If your program satisfies this simple goal then it is a good program.  You might be a fan of pilates, exercise ball training, kettlebell training, TRX, Olympic lifts or Yoga.  All of these can help and can be part of your conditioning.

What I am recommending below is just one introductory component of a year round program that you can do for 10-15 minutes before or after your runs.

Why should runners strength train?

Performance Enhancement

We have a great amount of research showing that lower body strength training, power programs, plyometric work and even some simple "core" work can improve mechanical efficiency during running.  The reason for this is debatable.  It is unlikely that strength training programs that see athletes doing a few sets of  10-15 repetitions translate to improvements in our physiological endurance capabilities.  Yet somehow strength and power programs lead to increased efficiency.  One theory is that strength training may slightly increase our muscular and connective tissue stiffness or even train the nervous system to modulate such a change.  In other words, strength training builds a better spring and running is nothing if not built on good springs.  Runners bounce they don't push.

Don't worry about becoming muscle bound.  This won't happen.  Putting on muscle mass is difficult and and even if you do it won't lead to a loss of performance

Injury Prevention

This is something we have been recommending for years but in all honesty we actually have little published research linking strength training with decreases in injury rates.  Sure, poke around on the internet and you will read about runners with weak glutes, weak hip abductors (I'm guilty of this) and weak hips in general and how these deficiencies are linked with current injuries.  The rub is that this is just a link in time (i.e. a correlation) and we actually suck at predicting future injuries.  Regardless, it is scientifically plausible that if we can increase the tolerance to tissue loading via strength training in a  novel and different manner from how we normally load our tissues (e.g. running) then we might expect some increases in the resiliency of our tissues to the repetitive stresses associated with injury (disclaimer: chronic, persistent pain is a whole other mess).  If you are in pain, strength training is a novel movement.  This novelty can sneak under our pain radar and modulate the brain's production of pain and even help resolve a painful running "injury".

Warning: Runners often train like endurance athletes instead of just athletes.  You need to choose exercises that make you tired before 15 repetitions.  You need to struggle and you need to push yourself.  If you can do 30 squats then you need to either get under a barbell or do one legged squats.  You are training strength not endurance.  Push yourself goddamnit.

Last Caveat: The exercises that might become easy can then be performed as a warmup or as  cooldown.

Alright enough preamble.  Below is the program.

6 Exercise Program:  All exercises are coupled with another exercise

I use exercises in pairs (couplets) and sometimes in threes (triplets).  This called a superset.  It is more efficient and decreases the downtime associated with the rest you need between exercises.  The exercises that are usually paired train muscles or even sides of the body (front versus back, push versus pull).

When, how much, how often?

  • before or after your run
  • two to three sets of 10-15 repetitions (if you aren't tired at 15 reps than you have to find another exercise)
  • this can be performed 3 times per week

Couplet One: High Knee Drive to Squat

1high knee lift
1high knee lift

Standing High Knee Drive

Standing tall drive your knee upwards. Brace through your spine.  This exercise can be preceded by a front scale.

Another option is hold your hip flexed (knee above hip) and perform a 6 inch knee lift with the hip already flexed.

Use resistance: add tubing around your knee or perform this on a 4-way hip machine

deep squat
deep squat

Deep Squat

Thats it. Squat deep.  One option is to shift your weight back and forth once you get deep.

You can combine these exercises by squatting, driving up and driving your knee upwards.  Then drop back into the squat.

Tip: vary the speed

Tip 2: add weight

Couplet #2: Core Couplet

front bridge
front bridge

The most popular exercises on the planet.    Bridging or planking.  Whatever you want to call it.

These exercises you work your front, your side and even your back.

You can do these exercises separate from one another or you can roll from one hold to the other.

sidebridge feet
sidebridge feet

You can hold the positions for 2-3 seconds or go nuts and hold for 30 to 60 seconds.  You will get benefit either way.  Your goal is to feel tired.  When you feel that your form starts to weaken then you can wrap it up.

Options: lift a leg, rock up and down, roll a little bit

Couplet #3: Single leg squat to lateral birddog (aka birddog hip airplane)

one leg squat
one leg squat
birddog with leg out and hip dropped downwards
birddog with leg out and hip dropped downwards

Lateral Birddog Hipairplane: this exercise is a modification of the good old birddog where you lift your leg to the back and your arm to the front.  The modification sees you lifting your leg out to the side and then dropping your hip that has the knee on the ground out to the side.  You will feel increased pressure in the outside of the hip.  Let your other hip drop to the ground and then lift it back up.  To really stress things swing other leg side to side.

One leg squat: you can do this with your leg out to the side like in the picture or you can have your leg out back.  I recommend hinging forward at your hip and NOT trying to keep your trunk upright.  Let it bend forward to increase the strain on your butt.

Go through that circuit.  Twice.  Its easy, takes 10-15 minutes and is good for us runners who really only want to run but know we should do something else.  You can do this one day a week and on two other days make up your own strength couplets.  Or just do this 3 times a week but in 4-6 weeks you should mix things up.  Add some speed, more weight, different exercises...train variety build capacity.

Related Programs

1. Runner's Strength Videos

2. Patellofemoral Pain Rehab Sheets

3. Bridging Variations

4. Stu McGill's Big Three

5. Hamstring Tendinopathy Strength Training Videos: Hint not just for hamstrings

A Summary of Techniques to Change Impact and Joint Loading During Running

Purpose: To review some of the data on ground reaction forces during running, the significance of this physical loading and how loading can be modified. WARNING: this post is massive.  It is meant as a working and evolving repository of much of the research on this topic.  It is a compilation that I would like to update as more work is added. I use a post like this as a living reference library so I don't have to search through an entire article to get the gist of it.  It is not meant to win a writing award. Skip to the bottom for a summary.

What is in this post

1. Ground reaction forces (GRFs) overview

2. Relationship between GRFs and Injury

3. Modifying loading with step rate

4. Modifying loading with foot strike style

5. Modifying loading with shoe wear or going barefoot.

What are ground reaction forces and impact loading?

When the foot strikes the ground during running the ground produces a force back against the foot.  The force can be broken into three directional vectors:

1. Vertical

2. Forward - Backwards (e.g. "braking" and then "push off")

3. Side to Side.

Most of the research has focused on the Vertical loading so I will too.  Vertical loading looks like this:

The first peak in force is termed the impact peak and results from the collision of the foot with the ground.  We can also look at how quickly this force rises and when that peak occurs.  This is called the rate of loading.

The second peak is called the active peak.  It corresponds to the point when the energy absorption has stopped (the center of mass is at its lowest) and when we start to "push" off against the ground.

Relationship between ground reaction forces (GRFs) and injury

The relationship is contentious.  It is simple to assume that less load or less stress on the body leads to a reduction in injury risk.  But this does not always pan out.  The human body has the ability to adapt and the variability across runners' ability to adapt is huge. Simply, we don't know how much load is bad for an individual person.  You can even argue that loading is good in that this is what stimulates an adaptation in the runner (e.g. stronger bones, stronger soft tissue, a better nervous system?).  What the cutoff is between good loading leading to adaptation and too much loading leading to injury is our Holy Grail of Injury Prevention.  The concept of loading and loading rate on injury in runners could be a long post itself - I will just link to some articles below and briefly touch on this area.

There is some suggestion that the rate of impact loading is related to stress fractures in runners.  See this post here and the abstract here.   We also have some suggestion that decreasing peak loading can influence stress fracture risk (abstract here and here)

We also have some great research by Dr Irene Davis linking higher impact velocity (e.g rate of loading) with stress fractures (link here).  Dr. Davis has also published case series showing changes in loading rates with feedback during running (abstract here).

Some links to follow for more information on this.

Davis and company (here, here, here, an outlier here)

Other researchers showing no relationship with loading and injury ( here and here)

So How Can We Modify Loading During Ground Contact?

In the following sections we will take a look at three methods that are used to change loading during foot strike:

  1. Changing step rate
  2. Changing type of foot strike (i.e. rearfoot versus midfoot)
  3. Changing footwear (or foregoing footwear altogether)

In an upcoming post I will review what other changes occur when we attempt to make these changes to impact loading.  Changes don't exist in a vacuum.  They could lead to changes in running economy, muscular activation or other unintended consequences that could affect performance and maybe injury risk.

The Bottom Line before the bottom

All three techniques are able to change impact loading and joint loading in some individuals but not in all individuals.  What we see in the research is variability and this leads to conflicting results across studies.  This is because there are other factors than the three above that influence the ground reaction force.  For example, you can change to a midfoot or forefoot strike and still overstride (see a neat video and case on this here).  The stiffness in our limbs can all influence impact.  This is what happens to some extent with kinematic changes with aging.  Older runners can have similar stride rates but still have greater impacts (for a brief review see here).  But lets look at some research.

A. Changing step rate

We can increase the number of steps we take while running.  Heiderscheit et al (2011) did such a thing (for detailed review of the study look here and here).  He increased step rate by 5 and 10%.  This is some of what they found:

At both 5 and 10% increases in cadence

  • decreased step length
  • decreased Center of Mass vertical excursion (less bouncing up and down)
  • decreased horizontal distance from the center of mass to the foot (i.e. less overstriding in front of you)
  • less knee flexion (excursion) during the foot contact (i.e. increases stiffness)
  • decreased energy absorption and energy production at the knee
  • decrease in the impact transient occurrence (there were times when runners did not have that sharp spike in ground reaction force plot)
    • decreased braking impulse

At a 10% increase in cadence only

  • decrease in foot inclination angle at contact (toes point down more)
  • decreased stance time duration
  • increased rating of perceived exertion
  • less hip flexion and adduction
  • increased knee flexion at initial contact
  • decreased peak vertical ground reaction force
  • decreased energy absorption at the hip

A note on the ankle

There was no change in the amount of ankle energy absorption when increasing cadence yet a huge decrease in the amount of energy absorbed at the knee.  This is most likely due to a lack of change in the ankle kinematics and how the foot struck the ground.  I would guess that changing cadence was not enough to change the type of foot strike.  If an individual went from a rearfoot to a mid or forefoot strike we would probably see more energy absorption at the ankle.  Take home point, is that a lot variables can influence impact loading.

A note on the initial impact loading and loading rate

The authors found that reducing step length decreased the occurrences of that sharp initial bump in the ground reaction force.  This is the impact transient and is what we most see in runners who heel strike - it is essentially the collision force with the ground. However, it was rarely seen (0-1 times in every 5 strides) only 56% of the time when increasing step rate by 10% (this lack of impact transient was seen 22% at preferred step length).  So notice this is just a trend in some runners.  If you notice with the study the authors did not calculate the average loading rate across all runners.  This is how we typically compare loading rates across interventions.  I would guess with the variability across the subjects we would not end up with a statistically significant change in loading rate.  Presenting the data in this way shows us that sometimes we get a change in the impact transient just not always.  As a refresher here is a lovely video of the loss of the impact transient with forefoot running.

http://youtu.be/XO4MruQov4Q

Hobara (2012 -abstract here ) had athletes run at 2.5 meters per second and also modified step frequency (increasing huge amounts of 15 and 30%).  They found decreases in:

  • vertical impact peak (VIP),
  • vertical instantaneous loading rate (VILR) and
  • vertical average loading rate (VALR).

The only issue with this study is how practical it is to have such a huge change in stride rates.  It is great for a proof of principle but we should question whether we want to do this in terms of running economy and even injury risk (i.e. you are taking a lot more strides thus increasing repetitions).

...and the other side of things (nothing is ever that simple)

But, these findings were mildly contrasted with another neat study that looked at changing a number of things (step rate, foot contact style and type of shoe) and the loading response.   Giandolini (2012)found the following when increasing cadence 10%:

  • no change in the rate of impact loading
  • no change in the impact transient
  • no change in the time that your foot is on the ground
  • a decrease in the aerial time (time you are in flight)
  • increase in stiffness (vertical)

These authors looked at the group average for changes in rate of impact loading.  They don't show their raw data so it is possible that there may have been some individuals who decreased their rate of impact loading and perhaps lost the impact transient during initial foot strike.  This would be consistent with the Heiderscheit study.

In this comprehensive study, these authors were also able to change a number of loading and kinematic variables with other interventions.  They did two other things - put runners in a racing shoe (versus a big bulky cushioned shoe) and had the runners switch from a rear foot strike to a mid foot strike.  They also combined all three changes (COMBI).    So why don't we take a look at this neat-o study along with other relevant studies that look at changing footstrike style.

B. Switching to a Midfoot Strike

The research suggesting changing foot strike influences loading variables

This simple change provided some pretty drastic results.  Giandollini et al (2012) found:

  • loss of the impact transient when switching (also found in the COMBI)
  • greater than 50% decrease in the rate of loading (also found in COMBI)
  • interestingly no change in step rate (this is of interest because we often assume that this happens with a midfoot strike.  We typically assume that running midfoot versus the heel naturally shortens the stride - suggesting that we can get changes in loading rates without decreasing stride length)
  • an increase in Gastroc (calf muscle) and Tibialis Anterior (shin muscle) muscle activity was found just before impact but not during impact.  However, the authors did not account for the electromechanical delay (i.e. the muscle turns on immediately but it takes time to take up the slack of the muscle to create force against the bones) that occurs with EMG muscle activity so we shouldn't conclude that the muscles are not creating less force during impact.  With the delay these muscles are creating force and are mostly likely contributing to the buffering of the impact loading response.

You can see a video version of this response in the video above from Dr. Lieberman.

...again it is never that simple.  Similar research has found different conclusions

Laughton, Davis and Hamill (2003) investigated fifteen habitually rearfoot strike runners and then converted them to a forefoot strike pattern in a single session.  The authors found:

  • increased average peak vertical ground reaction force
  • increased Anterior to Posterior GRF
  • Increased Anterior to Posterior loading rates
  • no difference in average or instantaneous GRF loading rates

some other findings:

  • increased dorsiflexion and calcaneal eversion excursion
  • decreased centre of mass excursion during foot contact
  • increased knee flexion at initial contact
  • decreased knee flexion excursion
  • increased knee and leg stiffness
  • decreased ankle stiffness

WHOA...this is very conflicting.  Sure is.  It again stresses that changing a single variable is not sufficient to change other variables. Changing to this type of forefoot strike pattern either increased peak loading, no change in loading rates, increased braking forces and increased knee and leg stiffness.  We don't know if stride rate changes but the increased anterior-posterior forces suggest that the forefoot striking may have been related to overstriding.  Last, in this particular study the forefoot strikers were not permitted to let their heels hit the ground.  They essentially ran on their toes.  The Giandollini suggests that converting to midfoot strike can be beneficial (in terms of impact and force variables) but there may be a correct way to do this.  i.e. don't just run on your toes

Further research showing variable impact loading with changes in footstrike

Becker et al (2012) in an abstract presented at the ASB 2012 concluded that foot strike pattern does not predict loading rates during shod or barefoot running.  With a subject population of 11 (this study was reported as ongoing so it looks like it may be more robust in the future).  The authors measured vertical impact loading rate and strike pattern in the runners when they ran either shod or barefoot.  What they were able to evaluate was how footstrike pattern related to VILR in quite a novel way.  The participants were not told to attempt to change their foot strike pattern.  Rather, they had people either run with their shoes or in barefoot and measured their footstrike pattern with something called a Strike Index while also measuring their VILR.  With these two measures in hand they determined how foot strike pattern related to VILR because some people would naturally change from a rearfoot pattern while shod to a forefoot pattern while barefoot.  So, there were few permutations on what could happen.  Here is a sample of what I see as relevant and check out the chart below for all the details.

Lets look at those instances where people RFS while shod but ended up switching to a forefoot strike while barefoot:

  • 12/16 switched from a RFS to MFS/FFS while 4/16 remained RFS while barefoot
  • of the 12 that switched 5 of them significant increased their VILR while 7 had no change.
  • of the 5 that showed changes when going to a MFS/FFS while barefoot all of them showed increases in loading rates while non showed decreases.
  • Figure 1 below shows no loss in the impact transient in subjects running with a midfoot strike

The flow chart below shows what happens to the vertical loading rate to individual runners when they either change to a midfoot/forefoot strike (MFS/FFS) while barefoot or remain heel striking (RFS)

The bottom line from this study is that a mere shift to a MFS/FFS is not sufficient to get less VILR.  This study is also confounded with the shift from the shod to barefoot but it again suggests that is not a sufficient condition to automatically assume you will get less loading rates.  Big limitation: there was no training or time allowed for habituation.  This is short term study and may not reflect what happens with motor learning over time. 

C. Impact and loading changes when we change our shoes

 I will cut right to the chase here.  Changing your shoes is not always enough to get changes in loading variables.  Big bulky shoes are knocked under the assumption that the ass of the shoe gets in the way and forces runners to land on their heels and overstride.  We assume that replacing these shoes with lighter shoes (and less of a heel to toe drop)  will lead to a change in how we run to avoid heel striking  (due to pain) and overstriding.  Lets look at the research on what happens in different shoes.

Possible Study Outcome #1: Traditional versus minimal shoes lead to variable changes in loading

Goss et al (2012) Accuracy of self-reported footstrike patterns and loading rates associated with traditional and minimalist running shoes (ASB 2012).

These authors looked at 57 runners who ran in either traditional running shoes (n=22) or minimalist running shoes (n=35).  There were no details on what these minimal shoes were.  The authors measured ground reaction force and were classified into either a rearfoot or forefoot runner.  This gave three categories of people: 1. rearfoot striker with traditional shoes (TSR) 2. Midfoot striker in minimal shoes (MSA) and 3. rearfoot striker in minimalist shoes (MSR).  Before doing the assessment they also asked the runners how they thought they struck the ground.  Here is what they found:

  • 1/3 of experienced minimal shoe wearing runners misclassified their running footstrike - they thought they were midfoot but they were hitting their heel.
  • the MSA group (midfoot minimal) had the lowest average vertical loading rates (52.8 BW/s), traditional shoe rearfoot strikers were next (68.6 BW/s) and the rearfoot strikers with minimal shoes had the highest loading rates (107.8 BW/s).
  • there was no change in peak ground reaction force across groups
  • vertical ground reaction force curves were different between groups.  Noticeable there is less of the impact transient in minimal shoes regardless of footstrike but midfoot striking with minimal shoes leads to the gentlest of loading rates.  See chart below.

Possible Study Outcome #2: Shoes versus barefoot lead to increases in joint loading

Kerrigan et al (2009) looked at the influence of running shoes on lower extremity joint torques in standard running shoes and barefoot (n=68).  They found increases in the following joint torques when going from barefoot to shod:

  • hip adduction
  • hip external rotation
  • knee flexion, knee varus, knee internal rotation
  • ankle internal rotation

In terms of ground reaction forces there were increases with shod running in:

  • medial to lateral GRF and Vertical GRF

with a decrease in the minimum anterior to posterior GRF

Stride length was found to increase from 2.15 meters (barefoot) to 2.29 meters (shod) although the authors suggested that this accounted for only a small percentage of the changes in joint torques.

Possible Study Outcome #3: Minimal shoes lead to increases in joint loading

Logan et al (2012 - ASB Abstracts here) GROUND REACTION FORCES BETWEEN RUNNING SHOES, RACING FLATS AND DISTANCE SPIKES IN RUNNERS

The authors compared the three different shoes and aspects of the ground reaction force (Impact peak (BW), loading rate (BW/s), peak braking and propulsive force (BW), peak vertical force (BW), stance time (s), and vertical stiffness (BW/m)) in runners (n=18) who were all habitual rearfoot strikers.  Further, these runners were college track athletes running between 5.67 -6.7 meters/s.  This is fast considering that running around a 5 meter/second pace will have you run 5 km in 16:40.   They found:

Impact peak and vertical stiffness significantly increased between running shoes and spikes. Differences between stance time and loading rate approached significance with trainers being lower

This again is interesting.  I don't know if these runners changed their foot strike with any of the shoes but it reiterates that changing shoes to a more minimal shoe is enough to positively lower loading variables.  In this case it increased them.  I would assume that these runners were still heel strikers despite the change in shoe.    This group shows that you can have less of an impact peak, less vertical stiffness and a trend to having less loading rate with a trainer than with more minimal shoes.  Take home point here is that our movement patterns involve motor learning...motor learning involves effort, time and conscious attempt to change how we move.

Possible Outcome #4: Shoe differences are minimal but going barefoot decreases loading variables.

...and now a contrary view Hamill et al (2011  with a detailed review here) in a study titled "Impact characteristics in shod and barefoot running".  The authors compared barefoot running with running shod in three different shoes of different sole thickness (1. A shoe with a 4mm heel and 0 mm forefoot; 2. a shoe with 12mm heel and 8mm forefoot and 3. a shoe with a 20mm heel and 16mm forefoot). The authors looked at the immediate response with these different shoes.  Again, there was no training or attempts repatterning a gait stride. Their results in a nutshell were:

  • switching to barefoot leads to an anterior footstrike pattern
  • barefoot leads to less 50% of the loading rate of all footwear conditions
  • impact peaks are still common with minimal shoes (a 4mm drop and very little thickness)
  • there is a trend to decrease loading rate with decreasing shoe midsole thickness
  • in general, shoes of different midsole thickness did not have different loading variables as runners in all shoes did not change their footstrike pattern

Possible Outcome #5: Minimal shoes show no effect on impact loading

The Giandollini (2012) study compared standard cushion shoes with a racing shoe (important note: the racing had a large heel to toe drop of 10.8 mm - thus some may not call this a minimal shoe despite there being less mass).  The authors trained the participants and had them run at the same speed with the two different shoes on.  The authors found no difference in loading rate, time to peak vertical load and peak vertical loading. The authors suggest that individuals continue to use a heelstrike style of running and that the minimal shoe did not coerce the runner into changing their running style.  What I find interesting is that even though the racing shoe is much lighter with less cushioning there are no adverse consequences to running with a similar style compared with the  normal cushioned shoe.  Below is a nice graphic representation of all of Giandolinni's interventions on the vertical ground reaction force.

Brief Summary of changing gait variables to influence impact loading

All methods can influence of impact and joint loading but not consistently.

Increasing step rate can decrease joint loading but does not always lead to a reduction in the impact transient or rate of impact loading

Changing to a midfoot strike does have evidence to change impact loading variables but again in some individuals we won't see any change

Changing to a midfoot strike may also result in other factors that increase the strain on the tibia (link here for a start to this interesting idea).  We can't say with certainty that everyone should be doing this change.  A follow up post must and will address this area.

Changing your shoes to lighter weight or minimal shoes also has variable effects.  Most importantly, instances can exist where your loading can increase when going to lightweight, minimal shoes.  Most likely due to maintaining the running style that you have adopted when running in your previous cushioned trainers

The Giandollini et al (2012) study is really quite lovely.  They look at as many variables and interventions that you can reasonable look at.  They show how many techniques of what we think might change impact don't consistently change impact and they also provide insight into the "whys" of this.  I also like their conclusion (probably because it agrees with something I wrote last year on barefoot running and foot strike style and I need reinforcement :) ) where they write:

our results show that running "barefoot-like", i.e. with a midfoot strike pattern may be an effective solution to reduce the magnitude of impact, as quantified through the loading rate

Related Posts

Running economy, barefoot, minimal and traditional shoes

Barefoot and foot strike style running biomechanics review

Running injury prevention

Running in the Backseat: A rationale for improving hip extension in runners

Poor hip extension is a favourite of boogeyman for all manner of back and leg injuries. I have reservations about its relevance to pain and injury in terms of how the hip flexors get tight and the relevance of regional interdependence to pain (see here and here). Yet, I do not completely ignore the possibility that hip extension limitations (or not using your available hip extension) can influence function...I just think its over-rated and over used. One area that limited hip extension is proposed to influence function is during gait.  Dr. Howie Dananberg has detailed this in his theoretical ideas about how functional hallux limitus (lack of big toe dorsiflexion) leads to lack of hip extension, which in turn causes a decrease in the stretch of the psoas, leading to the loss of passive muscle recoil (because no psoas stretch) to initiate leg swing during gait and and ultimately increases in stress on the lumbar spine that leads to pain. (see a review here and one from me here).  Another theory regarding running has been championed by Jay Dicharry which is slightly different and puts a strong emphasis on performance as well as the possibility of pain.

Jay Dicharry is a biomechanics researcher and physical therapist with a focus on running injuries.  He runs a gait biomechanics lab at the University of Virginia (blog here) and has published some excellent reviews (here) and original research in the area (here).  He has also a new book out on running injuries (here).  I am a big fan of how Jay explains running biomechanics and he does an excellent job in his book. In the book he proposes a possible mechanism where lack of hip extension may negatively influence runners.  Jay lays out an excellent case for how poor hip extension can compromise efficiency (I can get behind this) and may also increase injury risk (I'm still skeptical when anything comes to pain because of the complexity of the pain experience and the poor track record that biomechanics has in predicting pain but this is no fault of Jay Dicharry).

Theory in a Simplified Nutshell:  Limited Hip Extension causes Overstriding.

Jay describes the swinging leg as pendulum.  It has a front side swing (swinging forward to strike the ground) and a back side swing (backside mechanics that occur before the leg leaves the ground).  What Jay suggests is that if you don't have adequate hip extension the athlete will "sit back" while running and will have increased front side swing (see the picture above from www.goodguystri.ca).  In other words, the pendulum arc will be shifted to the front side and the runner will land with the foot too far in front of the centre of mass - aka: overstriding.  This problem will be compounded at increasing speeds when the athlete looks to increase their  stride length.

Jay suggests that running in the back seat leads to two things:

  • Increased metabolic cost associated with overstriding
  • Increased impact loading associated with overstriding

Lets look at these two in detail.

1. Increased Metabolic cost associated with overstriding

Two mechanisms may be at a play here:

a. Lack of hip extension loses passive energy return.   The muscle-tendon unit can be viewed as springs.  We use the passive energy that they store rather than merely actively contracting them.  The tendons store energy during impact (e.g. they start to stretch) and then they release that energy during the push off phase.  With limited hip extension it is suggested that the pendulum can not swing backwards past the dashed vertical line and the pendulum must then swing forward excessively.  Without the ability to swing backwards the runner doesn't have the time to release the energy that they stored during impact because they are not able to let their leg swing backwards.  

 

 

b.  Overstriding is inefficient and costs more muscular work.  When overstriding the center of mass of the runner increases its up and down motion.  This means we work harder to decelerate the mass during impact and absorption and then we work harder to accelerate the mass during the push off phase of running.  Further, with the ground striking leg being farther away from the body we are at a mechanical disadvantage for absorbing this energy.  Overstriding would then increase the load on the knee and may therefore predispose individuals to knee pain.

 

2. Increased impact loading associated with overstriding

                                            This one we have heard a lot and is the thrust behind shortening peoples strides, changing foot strike pattern, going barefoot or running in minimal shoes all in an attempt to decrease the rate of impact loading, collision force and joint loading when running.  The closer the foot is to the center of gravity at foot strike the less rate of loading and joint loads we can expect.  Heiderscheit (2011) published a recent paper showing  how manipulating stride length (decreasing it) can decrease ground reaction forces, braking forces and joint loading.  This is also the impetus behind Lieberman's work championing barefoot running - he contends that the combination of a forefoot strike and a foot strike closer to the body (i.e. what occurs with shorter strides which is proposed to  naturally occur when you run barefoot) decreases impact loading (a large review can be seen here).

 

Other kinematic consequences of limited hip extension

Not all runners with limited hip extension will end up "sitting in the backseat".  Some can increase their backside mechanics (the range of the leg swing backwards) by arching their back.  This is a common explanation we hear for the dangers of limited hip extension in runners and in all athletes or low back pain sufferers in general. In other words, if you don't have hip mobility you steal it from somewhere else (e.g. regional interdependence).  In this instance you get the range from your spine. Many authors have speculated that this increases ones risk for low back pain and for hamstring strains but again the data is not there.  However, if you are  having aches and pain with running this may be one area you could modify to modulate your pain response. Sometimes getting out of pain is just changing a habit, providing something new and different to our body (and brain) and you can feel less pain.

Critique and Comments

What I like about Jay Dicharry's opinions in this areas is that he has access to data and equipment that can support his views.  He is fortunate to have an impressive biomechanics laboratory and he mixes his clinical wisdom with the data is he is able to collect.  Questions/ideas that this theory presents to me are:

- how regularly does a reduction in hip extension lead to overstriding? Is it really the loss of hip extension that causes overstriding or are there other variables.

-if the pendulum arc is shifted forward this implies to me that there should still be enough time for the leg to load and store elastic energy because we haven't shortened the arc just shifted it forward with the overstride.  I could see how there is less time to load and store elastic energy if the actual foot contact time was reduced because of the necessity to take a shorter stride.

-this is still an unpublished hypothesis.  Like all theories of injury or performance it does need to go through rigorous testing.  I look forward to seeing these concepts tested and published.

-the vast majority of people (more than 90%) probably run slower than an 8 minute mile (5 minute kilometer). Strides are typically small and there is a plenty of ground contact time. With plenty of ground contact time the athlete would be able to release that energy.  With less speed there is less impact loading in general and this would provide a buffer for the slight increase in loading with the overstriding. I would question how relevant this is to contributing to injury - the simple biomechanical idea of increases loads being associated with injury is not well supported.  It is not a direct relationship.  In a runner with limited hip extension I would assume they have always had limited hip extension and this would have given them a lifetime to adapt.  Lots of individuals run with greater impact loads and joint loading (even at the same speed) and they may not be more prone to injury - this is even what happens when we age (see a quick review here)

 

-I don't doubt that people might show up with pain in their knees and also run while sitting in the back seat.  I also don't doubt that changing how they run (or stretching their hips) might be correlated with a decrease in pain.  Seeing these correlations often lead us to thinking that it is the biomechanics that cause the pain when it can be many other factors.  Last, even the act of changing the biomechanics can result in a resolution of pain but not because you changed the biomechanics.  It can merely be the act of change, setting a new contest for running, doing a relatively novel and what is assumed to be a threat free way to run that can result in less pain.

-with respect to Performance I have little say.  This is the most intriguing aspect to me.  I would love to see some research showing improvements in running economy following increases in hip extension.  Jay has laid out an excellent argument for how this style of gait is inefficient.  This is certainly something worth tinkering with in athletes who are pushing their limits.

 

 

The relationship between functional tests and athletic performance: Part I - The single leg balance test.

Background: Testing and assessing an individual is popular.  There is an old saying that if you aren't assessing than you are guessing.  The assumption here is that the tests and assessments you do are somehow relevant and meaningful yet I would suggest that the majority of tests and the information gleaned from them hardly change (10% ish) a therapeutic approach once you have heard your patients history. I can have a patient with knee pain and run them through 30 different tests and the results of those tests may hardly change my treatment.  Tests have to provide us meaningful information that we can do something with.What the hell am I talking about?

This blog post is the first of what I hope to be many posts that review the research on our physical tests of purported function.  We make a lot of assumptions about the tests that we commonly use in the clinic.  For example, someone might tell you that your hamstrings or psoas muscles is tight and this will cause you to be hyperlordotic (pelvic anterior tilt) during running.  Or you might hear that you suck at doing a squat and without being able to squat your form during other activities will suffer.  Ultimately, "failing" these tests can lead to you spending time doing lots of "corrective exercise" to fix a test.  This fix is assumed to help with function in other realms of activity.  I want to explore the assumptions behind the tests we use and then the purported fixes that follow.   Some of the topics I might explore:

- assessing tightness in a runner and whether or interventions influence running form

-  how strength training influences joint biomechanics/dynamic form

- how tests of static function relate to dynamic form (e.g. running)

- how simple dynamic tests (e.g. a squat) relate to dynamic form/joint biomechanics

- how measures of joint strength or ROM relate to dynamic form/joint biomechanics

- whether dynamic tests (e.g. a single leg squat) actually give insight into what they are supposed to be giving insight into (e.g. pelvic stability, hip abductor strength and a surrogate for hip control when running etc).

I have touched on these ideas in a number of other posts below:

- specificity of movement training (looks at our ability to change posture) (link here)

- the inability of tests to identify functional hallus limitis  (link here)

- weakness of the prone hip extension (Janda) test. (link here)

So here goes with a look at a common test for runners...

The Standing on one leg balance test is not a relevant test for Runners

Whoa, quick disclaimer.  This first post is an opinion as there is no evidence that specifically looks at this.  However, there is plausibility and I want to make the argument that being able to balance on one leg has nothing to do with the act of running.  This is a common test advocated by rehab professionals (many of whom I greatly respect and one has good book out on running biomechanics and injury here) looking to screen for deficits in function that are assumed to affect ideal running.  But I just don't see it.  It makes no sense to me so if you are reading this and think I am wrong please let me know.

The one leg balance test has you simply balancing on one leg with your eyes open or closed.   If you can't do it the assumption holds that you will be prone to injuries during running or you  may end up with some sort of issues with your running form.  The test is based on the idea that running is merely a succession of leaps through the air interspersed with balancing on one leg until the next leap.  I would respectfully suggest not.  Here is my reasoning:

1. The skill of running is completely different from the skill of one legged balancing. Running is not balancing on one leg as you are not static like you are during the balance test.  These two tasks are completely different. And we should not expect that one can be a surrogate for the other and reflects the same demands.  Our ability to balance is activity and context dependent.  I don't think we can assume that balancing skill in one task will carryover to another completely different task.  The same holds true for that crazy dead fad of doing squats on BOSUs or balance balls with the assumption that training this form of balance will carryover to the balance needs of a golfer or hockey player.  The latter is from Mars and the former is from Uranus.

                                                                   2. Static versus Dynamic Analogy

Running is dynamic.  You do not pause and balance on one leg.  Comparing one leg balance to running is like comparing the ability of a stationary top to balance on its point with the ability of a SPINNING top to balance on its point.  Suggesting that we need to be able to balance on one leg in order to run safely is like arguing that in order to ride a bike properly you have to be able to hop on the bike, clip in and then balance in place without moving.  I have been having my five year old do this for months before I will let her ride her bike and surprisingly she still can't ride a bike...and that bruised little monkey hates me for it.  (Obvious disclaimer: I am kidding).  But this example illustrates my point.  If it seems absurd on a bike then it is just as absurd on your feet.

Caveat of Ignorance

I reserve the right to change my opinion with new research or with fresh ideas.  I can also be convinced to think otherwise.  My mind is not as closed as my writing might indicate.  As a further hedge I also recognize that it is possible that some cross sectional study might come out and suggest that one leg balance is compromised in runners with knee/ankle/back/hip pain.  I don't doubt a correlation might exist BUT this does not imply that the decrease in balance ability is the cause of the pain.  This can merely be correlation.

Last, this does not mean that one leg balance training can not be beneficial for runners in preventing injuries or improving performance.  The act of doing one leg squats, one leg hops, hip airplanes, front scales and other great exercises could certainly improve your balance and would also change other aspects of muscle function.  In this case the improvements in balance could be secondary to other aspects of improved function that are the true drivers of improvement in performance and injury resilience.

Last point, honest- perhaps we over assess and our assessments change nothing in practice

What I think can be argued with this assessment test (along with many other tests) is that it just isn't necessary and is plausibly not valid.  If I am working with a runner or an athlete their conditioning program would be all encompassing and comprehensive.  This would include exercises that ultimately improve their balance along with other variables.  I don't need a rudimentary test to tell me to add these exercises.  I just need that human in front of me that tells me that they want to run and be an athlete.  I don't want to freak them out because of their shitty balance or advise against doing these wonderful exercises because they have great balance during a static, albeit not relevant to running test.

Case Study: Unexplained dead leg when running. Altered nerve tension?

Purpose: Demonstrate a case of an altered nerve tension in a runner that may be exacerbated by their running technique. Case Details

Female, late twenties, competitive runner (sub 20 minute 5km, 1:30 half marathon, 3:15 full marathon)

Symptoms

- 2 year history of left lateral lower leg pain that comes on with running

- begins around 20-30 minutes into a run and often feels like she can't control her leg with a sense of numbness (like she might fall)

- but no obvious swelling, shininess or pain in the anterior compartment during these bouts

Select Physical Exam Findings

- neuro screen, strength, ROM, single leg squatting, usual "functional tests" are all normal

- no significant pain on palpation of entire lower leg

- positive Slump test with a bias toward the superficial peroneal nerve.  This also occurs during a straight leg raise test with a superficial peroneal nerve bias.  The sensation felt is the same as that felt during running.  The video below is essentially the test movement (except change the ankle dorsiflexion for plantar flexion/inversion)

http://youtu.be/Xy1Lv3FK2Dk

Running Analysis

In the video below I noticed two things that may be significant.  This runner is predominantly a forefoot striker even at slow speeds.  Quite rare.  She essentially reaches out for the ground with her forefoot.  If you notice her knee it is actually quite extended just before foot strike.  This is not normal. See a kinematic review of running here. There is usually quite a bit of knee bend before landing and of course on impact.  Simply, this runner overstrides with a forefoot strike. She does this both in shoes and in socks.  This position is similar to the Straight Leg Raise test with a peroneal nerve bias and it may be contributing to the "funny" feeling in the leg.  A review of running biomechanics with video can be seen here.

http://youtu.be/h7W7cWYhCDw

Differentials

I can't rule out exertional compartment syndrome but I also can't confirm that with ease as the test would take over 3 months to get here in Toronto.  And Andy Franklyn-Miller (UK sports doc with a great deal of experience studying this type of thing -  website here) would suggest that this test is even questionable for this condition and we might even want to question the condition itself.  So I keep the exertional compartment idea in my head and look at other possibilities.

Why I question the compartment syndrome is the positive response I get when I stress the superficial  peroneal nerve with neurodynamic testing.  I don't believe that this is a classic response for exertional compartment syndrome suggesting to me that we have an altered neurodynamic on our hands.

Treatment

- explain pain, always explain pain

- at home - every hour, 5-6 nerve sliders for the peroneal nerve (video below but don't dorsiflex the foot)

http://youtu.be/y-cXei4e_wM

- running changes: this is tough but our runner is working on a midfoot strike and is trying to cue the idea of landing behind her (this is impossible but it can get the idea across).

- I also treat the "container" of the nerve.  I do gentle soft tissue work (I used to be an  A.R.T guy but I am much gentler now and don't believe the theory they propose) along the entire sciatic nerve. I think that I am really the nervous system and ultimately influence the muscle and the peripheral nerves with my manual therapy.  You can explain this treatment anyway you like. I choose a neural based explanation rather than thinking that I am digging out adhesions.

- I believe runners should be strong.  And not just runner strong - athlete strong. This runner has had previous high hamstring tendinopathy/tearing (or possibly sciatic nerve or all the little nerves back there irritation) so she is on a heavy resistance training program for everything.  I don't emphasize anything - I just train for balance, capacity and variety.  She gets exercises like one leg deadlifts, deadlifts, squats with bands, hip thrusts, hip airplanes, bridges, clamshells, one leg squats, one leg lateral wall squats, nordic hamstrings, push ups, suitcase carries etc.  Click here for a "hamstring" injury for runners sample program for videos

Is she better?

Sorry, don't know yet.  Just started.  Any ideas please let me know.  I can say that after I gently treat the region around the sciatic, tibial, peroneal nerve we are able to decrease the sensitivity associated with the SLR testing. This is a good sign. I am cautiously optimistic.