Hamstring Tendinopathy: Sample Rehabilitation Program Videos

Audience: Therapists and Patients Purpose: This post is video overview of the sample exercise progression I might advocate for patients (primarily runners) who present with persistent longstanding high hamstring pain.

Background

Runners, particularly faster runners, will often present with high hamstring tendon pain.  The pain is typically felt where the muscles insert into the bottom bone of the hip (the ischial tuberosity).  In addition to the hamstrings the adductor magnus can often be involved.

Patients will feel pain with running (particularly at speed), pain when pulling their shoe off with the foot, often pain with sitting and even some pain getting out of a chair.  When I see these patients they have often had this condition for months or years.

When the pain has been around for months you may want to consider this dysfunction a failed healing response.  Throw the ideas about inflammation out the window.  These patients have rested their leg and even done some remedial exercises but to no avail.

 

The exercise approach is simple – TISSUE RESPONDS TO LOAD.  Injury treatment is the judicious application of stress – applying this stress to an injured tissue is stimulus for adaptation.  This application of stress to the  non-responding tissue (i.e. your hamstrings) can be complimented with all other treatment techniques and assessments.  In addition to applying stress we also want to try the find the cause of the initial hamstring overload (Good luck).  Some possibilities being:

1. Weak glutes

2.  Poor trunk strength/endurance/control

3. Restricted joints anywhere (feet, fibular head, SI joints, Thoracolumbar junction)

4. Excessive anterior tilt while running (motor control or tight passive/active tissues?)

5. Overstriding

6. Understriding and “hanging” on to your hamstrings when running (rare)

7.  The big daddy – too much, too soon, for you at that point in time.

8. Poor tissue quality (sometimes our muscles and tendons just need a little rubbin’ lovin’  e.g. ART, myofascial, Gua Sha, Acupuncture, general massage)

OK, enough lecturing, you are still in pain

My clinical take is that many athletes get issues 1-8 somewhat taken care with usual care. (This assumes it is not crappy run of the mill care where someone sticks ultrasound and a TENS machine on you and then tells you to stretch). After the usual care (which is the non-horrible kind) patients are then given remedial exercises for the hamstrings (stretching, bridges, curls) but they still aren’t responding.

With these recalcitrant cases we often then need to stress the tissue harder (or find the other key link in the dysfunction).  Inspired by the painful eccentric loading protocol’s variable success in tendon pain (a nice review here and here) I choose to ignore some of the eccentric loading exercises alone and also add heavy resistance training.  For my patients, eccentric loading means that you just work a muscle as it gets longer not as it gets shorter.  It is like lowering a weight but never picking it up again.  It never made sense that concentric exercises would negate the benefits of eccentric exercises and why would daily loading be necessary? (Update: I should listened to  Jill Cooke's podcasts (search on itunes if you care), she is an amazing tendon researcher and has been saying this for a long time).  I had good success with heavy resistance training  but did not have any research to support it.  Fortunately, I found some (click here on a comparison of heavy resistance training versus painful eccentric loading), so I can go back in time and support my previous views and say I was evidenced-based(this is definitely some confirmation bias on how I select the papers that I read).

 

Here are some exercises that I often recommend for runners

A warning, don’t do these willy nilly.  Have your therapist or strength and conditioning coach guide you through these exercises and create the appropriate parameters (how much, how often etc).  Not all of these exercises are meant to be done on the same day.  Work with a professional to create a program.  You can also be doing a lot of other exercises for your core or upper body.

If you are my patient and aren’t sure, email me.

Stage One (2 weeks)

Rationale: Train the glutes, get the  hamstrings ready for more load, train the trunk, say hello to the external hip rotators

Bridge Series (Front to Side)

http://youtu.be/nOw87GtKgFY

 

Back Bridge

http://youtu.be/rjNLyGcfV8E

 

Bird Dog

http://youtu.be/xGHusEEYj6U

ClamShell

http://youtu.be/2aVy6sDVa4c

 

Squats with External Rotation

http://youtu.be/Js0JFw7N4QY

 

Perform the squat as seen in the video below but have tubing around both knees.  When squatting down attempt to press the outside of your knees against the tubing.

The squat in the video is not ideal.  You DO NOT want the knees to start the motion.  The first motion is the butt going backwards with the weight through the heels and the balls of the feet.  The squat starts with a bow or a “hip hinge”.

Hip Flexion Drives

http://youtu.be/HfZnPU1-XhI

Put a cable or tubing around your knee.  Drive your knee forward training your hip flexors.  If you can do 15 easily then add more weight.  Try to not let your spine bend forwards or backwards.

Cabled Hip Extensions

http://youtu.be/knovP_bSv4s

This exercise attempts to mimic the function of the hamstrings during running.  The hamstrings and glutes work to pull the swinging leg backwards toward the ground and support your weight during foot strike.  Hamstring strains occur during this phase.  Click on this link for a post about hamstring function during running (click here).

With this exercise you want a cable or tuning tied around your ankle.  You then pull your leg backwards with your butt and hamstring and slowly return your leg back to the start.  Try not to arch your back during this exercise.  Focus on feeling tension in your hamstrings and glutes.  You will also feel this in the leg that is standing on the ground.  For balance it is OK to grab onto something while doing this exercise (it will also take the strain off the leg that is on the ground).

Stage Two Learning Phase(weeks 2-6)

Repetitions: 8 to 12 (2-3 repetitions shy of muscle failure or form breakdown)

Sets: 1-2

 

Bridge Series (Front and Side)

 

Back Bridge Walkouts

http://youtu.be/TsjQOLHupCE

 

Deadlift Learn (light weights)

http://youtu.be/Mp_XwsEGQ-4

 

One Leg Deadlift

http://youtu.be/F8XBCWHJ3FA

 

Hip Airplane

http://youtu.be/0okjZoaSRLA

 

Cabled Hip Extensions

Cabled Hip Flexion

Stage 3 (weeks 6 to 12)

Repetitions: 4 to 8 (1-2 repetitions shy of muscle failure or form breakdown)

Sets: 2-3

Nordic Hamstring Curls

http://youtu.be/BgLDQ83jh7I

 

Bridge Series (Front and Side)

Single Leg Bridge Eccentric Slide Outs

http://youtu.be/8pw-Ek5AxWM

Deadlift

One Leg Deadlift

Hip Airplane

Cabled Hip Extensions

Cabled Hip Flexion

Running Injury Prevention: A brief review of what we know...and more of what we don't

Audience: Runners and Therapists Purpose: A quick guide to running injury prevention.

Preamble Injury prevention for runners is not rock-solidly founded in science… and may not even be possible.  With runners it is more injury management.  You are going to get injured and  you are going to have some aches and pains.  The ideal is to minimize your lost training time and avoid some of the nasty injuries that can jeopardize your long term running and goals.

As I said, injury management is not a science.  What works for one person often does not work for another.  Unfortunately, there are few strong statements that we can make about injury prevention.  If a therapist tells you that you must do “x” to prevent injuries then for the most part they probably don’t know what they are talking about.  Injury prevention articles tend to glom onto whatever is fadish (e.g. core stability, dynamic warm ups, stretching, minimalism).  All of these may play a role but there is certainly no absolutes.

This article will be some opinion that is informed by some research.  All of the suggestions can help some of the time.

We can roughly categorize injury factors into extrinsic factors (something outside of yourself) and intrinsic factors (things about you).

Injury Prevention cheat sheet: I have attached a pdf file simple running injury prevention sheet oct2012 that is a general overview of injury prevention for runners and some exercises that may be helpful.  For therapists, please feel free to use this for talks for different athletic groups.

 

Extrinsic Factors

1. Have a running plan and seasons

Runners are NUTS.  We just want to run…all year round.  What other sport does this? Sports have seasons, sports let you prioritize different aspects of your training throughout the year.  Sports have off-seasons, pre-seasons and competition seasons.  We need this too.  So what can you do?

Get a good, progressive running plan. Follow it.  Don’t do too much too soon.  Those three pithy sentences are everything you need to prevent injuries…for the most part.  What are the basic elements of a good plan?

a. Different training cycles throughout the year with goal races chosen at times for you to peak

b.  A progressive training plan that allows increases in mileage that you can handle.  This might be a 10 percent increase of weekly volume that is mixed with plateau weeks.  But be flexible.  Maybe you can only handle 5%.  You have to increase your volume and pace slowly.  There are numerous books and online guides that can help you increase your volume and speed safely (see therunningroom.ca,  Jeff Galloway, Jack Daniels’ or Run Less, Run Faster).  Here is a sample of the Furman University “run less run faster” 3 day a week training program – Click here

 

2. Be flexible about your running

Sometimes you need to ignore number one.  I just advised that you follow a specific running plan of whatever coach you fancy. Unfortunately, many plans are not tailored to you but are designed for the average plus/minus a standard deviation about said runner.  If you are feeling beat up and getting injured than you need to modify the program.  Don’t feel bad about this.  We are all different and should not expect everyone to do the same thing.  Having an experienced coach can really help you through this.   This is why I recommend coaches (a la Nicole Stevenson) or some very great instructors who are also great athletes at different running programs. Click here for a great running blog from a Running Room instructor who is also a great runner.

 

3. Listen to your body

This is really about overtraining.  If you are not able to make your prescribed work out times, are consistently feeling run down, ache all over and ache specifically during runs then maybe you need a mini-taper.  Just a 3-7 day volume and pace reduction to get you charged up again.  Talk to your coach and listen to your joints.

 

4. Equipment

Shoe science ain’t no science.  Your feet and body tell you what feels good.  Read below for more on footwear, foot striking and barefoot running.

5. Be Healthy

Your body is an adapting machine.  Pro athletes are not only stronger and faster than you.  They can also recover better.  Their bodies are better at adapting to the strains placed upon them.  If they get injured they adapt faster.  When they train hard they adapt and are ready to handle that new load.  You need to optimize your body’s ability to adapt.  Here are some suggestions and I repeat, they are not hard and fast but work for many people.

a. Sleep more

b. Eat better (see a dietician, eat real foods)

c. Prepare your body (see the lower section on Maintenance Exercise)

d. Treat yourself to someone else’s hands on you (try Physio, Chiro, Massage).  All of these things (name a technique – ART, Graston, Fascial Manipulation, joint manipulation) can help some people some of the time.  I often look for minor dysfunctions (or at least what I presume to be a dysfunction which is still a murky construct) in joints before pain has reared its head in an attempt to prevent future problems.  The vast majority of pro athletes will have this type of manual therapy work done regularly.  You may or may not need it – try it but beware of hard sales and any catastrophizing on the part of your therapist.  A lot of therapists will take an x-ray or perform some scan that tells them how incredibly dysfunctional you are and if you don’t get several treatments for a prolonged time you will be ruined.  This is poppycock.  Avoid these people.  No one is that effed up.

 

6.  Did I mention follow a good training plan.

 

INTRINSIC FACTORS

 

1. Anatomical or structural things about your body are WAY overrated.

Knock knees, flat feet, high arches, wonky hips, scoliosis, femoral anteversion.  These are all things you can do nothing about and also have no relationship to injury.  Please don’t worry about this and don’t let some one tell you they can correct a problem that is not a problem.  This is catastrophizing and worthy of your disdain.

2. Orthotics – not really intrinsic but they still try to affect you.

I have a huge ambivalence towards orthotics.  The research behind their prescription and the rationale for what they might do is rather weak, conflicting and often does not follow common sense.  Yet sometimes I use them with patients (very rarely) and have patients that swear by them.  I know marathoners and Ultra runners that absolutely feel that they need them to function (whether this is a good thing or is another problem that should be addressed is another issue).  My bottom line with orthotics is that they are not magic, they may help you as they have helped others and there is no certain way of knowing whether you will respond fantastically to orthotics.  All of the assessment tools that are typically used for the prescription of orthotics have not been sufficiently proven.  That being said they may be worth trying.  If you read this paragraph and thought that I said a lot without saying nothing you may be correct.

 

3. Stretching

So popular now.  So popular to hate it and so popular to love it.  The hate comes from decades old research suggesting that acute stretching decreased (transiently) the strength and neural drive to muscles during explosive or high intensity exercise in relatively simple exercises (e.g. vertical jump).  This loss of strength was not found in some complex exercises (e.g. kicking a soccer ball) and I was unable to reproduce a loss of velocity in some preliminary research looking at the golf swing.  There is also a great deal of research suggesting that stretching before or after exercise has no injury prevention effect (but no harm effect as well).

 

As for running there is some research that suggests that stretching immediately before running makes you less efficient.  Alex Hutchinson’s blog (sweatscience.com) really illustrates these studies…but there are previous studies and current research that does not agree with this work.  Additionally, there is some research that suggests that if you do a warm up after you stretch then this takes away all of the negative aspects of stretching.

Because of all this most people suggest that you stretch after you run.  I often ask, why stretch at all if you don’t have a deficit in your range of motion?  We are  not gymnasts, we don’t need a great deal of range of motion so unless you are lacking some thing there may not be any benefit to stretching at all.  In terms of injury, the relationship between any injury and stretching is very poor, non-existent or occasionally present. Which leads us to…

 

4. Flexibility

Having more flexibility or lacking flexibility is not consistently related to any injury related to running.  My opinion on this one is that this must be taken on an individual basis.  If you are constantly getting injured and have flexibility deficits (relative to your peers) or have asymmetries between sides of your body than maybe you need to work on this.  If you are relatively injure free, have never stretched then why should you start? Because some physio told you to…don’t bother.  A quick qualifier, if you are reading this as a therapist and want research to support this, I have nothing.

 

Further, runners are stiffer than others.  This allows them to bounce (to store and release elastic energy).  This increase in muscle and tendon stiffness maybe increases their efficiency.  And if you want to get technical…

 

Stretching does  not change muscle stiffness, it only allows you to tolerate more muscle stretch.

 

In my opinion, I can’t rationalize every runner starting a stretching program.  That being said if you love stretching and it works for you then please do not stop.

 

 

5. Warm Up

Yes, please do.  Prepare yourself for your run.  Move your limbs and body in a manner that will be required during your sport.  Start slowly and progress.  This is a warmup.  Easy, no? Start running slow and build to speed.  Do form drills (As, Bs, Cs), Do strides, Do Skip, Do Shuffle, Do Carioca, Do Backward running.  Swing your legs back and forth and side to side.  Swing your trunk around.  There, that is warm up.

 

6.Strength Training

 

YES, YEs, Yes, yes.

 

Absolutely do this.  Before everything talked about above except following a good plan (that is always priority #1).  Strengthen your lower body, your hips, your trunk and your upper body.  What consistently shows up as factors related to injuries is some sort of muscle strength weakness or imbalance.  In runners, the “core” gets all the press (although it should not because the research is not there yet) but the HIPS have all the science.  Hip flexor and hip abductor strength and endurance are consistently related to lower extremity injuries and occasionally to lower extremity faulty mechanics that relate to injuries (although this is debatable and worthy of an article).  I am also aware that the predictive ability of having weakness does not relate to future injury for may injuries (i.e. we know that current ITB pain is related to current hip abductor weakness however, there is little predictive research suggesting that people with weak hips end up with injured ITBs) and I have some reservations about this research and think that strength training has benefits above injury prevention that can still justify its inclusion.   If you have injuries then strength training is fantastic for you.  Please see the following links for strength training articles on different topics:

Please note, some of these links are dead as I lost a lot of articles with some sort of spam infestation.

a. General Runner Strength Exercises

b. Hamstring Strain or Tendinopathy Exercises

c. Spine Exercise Videos

d.  The importance of hip abduction

e.  The importance of hip flexion

f.  The importance of balance and proprioception exercises.

g. Patellofemoral pain exercise sheet

 

7. Running Mechanics

Don’t change it if it ain’t broken.  And don’t change without help.  You need guidance from a coach, from a video camera or some other feedback mechanism.  Be cautious of changing irrelevant deviations from normal.  Caution aside here are some things to look for in what may be considered ideal:

1. Stride Cadence: at speeds greater than 6:00min/km you may want to be taking greater than 170 steps per minute.  Count the number of times your foot hits the ground in a minute – it should be 85-90.  Sprinters take upwards of 230 steps per minute.

2. Foot Strike: it may be more important to land with your foot closer to your body rather than what part of your foot touches the ground.  The footstrike debate will not die because we do not know the answer yet.  Here is a detailed post on foot strike mechanics.

3. Knee Valgus/Internal Rotation: this is a common “kinematic” (meaning how your body moves) flaw that is often related to running injuries.  Three big things happen:

a. your upper leg is slanted inwards

b.  your hips can appear to drop

c. your knee can be rotated inwards

 

All of these factors are often associated with weak hip abduction strength, poor hip abductor endurance and knee and hip injuries.  These variables are often theorized (but not proven) to be related to foot overpronation and possibly an excessive amount of anterior pelvic tilt.

4. Pronation – we don’t know if this is a factor.  In some studies it is the speed of pronation that is related to injury.  In other studies the lack of pronation can be related to some injuries.  Correct this or attempt to correct it if you are having consistent injuries.  I would be cautious of correcting (even if you could) this if you have no significant problems.

5. Impact loading – Run softer, seriously.  If you can really hear yourself clomping the ground then try to run softer.   Take shorter strides, even work on changing your foot strike for parts of your run.  Elevated impact levels and often the rate of how fast you impact the ground are often related to injuries (specifically stress fractures).  If you have a history of stress fractures look at your stride rate and how hard you hammer the ground.

 

8.  Minimalist/Barefoot Running

A very interesting area…but no world records and no elites are running barefoot.  While our ancestors may have done this they did not live past our middle age.  We know that impact loading is different in young runners than “old” runners so how do the benefits of barefoot running translate?

 

My on the fence position is that there is no definitive research either way.  Don’t through out your old clunky shoes but don’t discard the idea of adding some minimalist training into your work outs.

 

For a review of the science please see here and here.

 

If you have made it through this post please check back regularly.  This post is a mere framework that I will be adding onto throughout the next couple of months.  There are number of greater articles on other people’s blog posts that I have not linked to.  I will also be reviewing the literature in a number of different areas in the next little while.

 

All the best,

 

Greg Lehman

Physiotherapist

 

Nerve Slider Videos: Calming down that irritated nervous system

Audience: Patients Purpose: Demonstrate simple movements to calm, move and make healthy some irritated nerves. Disclaimer: Not to be done if painful. Do 5-6 to start. Always under health professional guidance.

Radial Nerve

http://youtu.be/3HkILi6rwR4

Median Nerve

http://youtu.be/npFZL_nWP6g

Ulnar Nerve

http://youtu.be/J3GThNaZqhQ

 

Musculocutaneous nerve slider

Very similar to the radial nerve but instead of bending your wrist so that the back of your hand faces the floor and your palm faces backwards you should let your palm face upwards, keep your thumb tucked in and then tilt your wrist to the side of your pinky finger.

This slider may be helpful with those with anterior shoulder pain that are told they have bicipital tendinopathy.

http://youtu.be/tjsOuaEF68c

Sciatic, Tibial or Peroneal Nerve (Slump Slider aka Flossing)

http://youtu.be/y-cXei4e_wM

Sciatic, Tibial or Peroneal Nerve (Long sitting slider)

http://youtu.be/bgN4X0Qpqkk

Running mechanics video - great for comparison with your form

Audience: Runners and therapistsPurpose: A reference to compare running technique

Limitations: Many of us assume that there is one right and better way to run.  Deviations from that ideal are assumed to lead to injuries and decreased economy.  This is still a debatable concept.  Everything I write can be questioned so please do so.

Below is a video of Nicole Stevenson (www.nicolestevenson.com).  Nicole is Canada's former number 1 in the Marathon with a personal best below 2:33.  Nicole is also a running coach

I wanted to highlight some probably beneficial components of her running gait.  Future posts will look a deviations from this gait and how they might relate to injury.

Key Points on her Form

- cadence changes as speed increases.  When running less than a 5 min/km her cadence is less than 180 steps

- foot strike is midfoot with one odd exception.  When running at higher speeds she tends to heel strike on the left.  Interesting, Nicole has had some achilles problems on the left.

-the knee does not fully extend prior to impact, it lands bent and does not fully extend even when the foot comes off the ground to start the swing phase (i.e. at push off)

- there is not a significant increase in hip extension when moving from slow to fast speeds (ripping into the "psoas" with some sort of release technique may be questionable).  While the thigh is further back this is mostly due to an increased trunk extension

- the hips stay relatively level (no dropping) during foot strike and the knees don't cave in

-the arms do very little in terms of driving forward.  We should surely question the role of the arms in producing power.  They do not do this.  Nor do they significantly tension the thoracodorsal fascia and some how stimulate the opposite Glutes to fire.  The glutes fire because we are driving our leg back to the ground.  There is no evidence that the arms are required in this.  One misquoted and abused paper by Mooney et al (2000) does not support this idea. 

http://youtu.be/07PsYlhAVts

Persistent Pain Resources for Patients

Audience: Patients Purpose: to provide some information about the pain experience

Why?: Understanding pain can help modify it

 

I don't pretend to understand everything about pain.  It is incredible complex and what we know is certainly involving.  However, there is a lot of misinformation out there even from people that should know better.  This article will link to a number of information sites that help explain pain.  This is important because it helps you understand why things hurt.  Understanding why something hurts can decrease pain but can also help you function better.  Some basic concepts:

 

1. Pain is a perception.  Signals (e.g. nociception or even pressure) come from the body and the brain creates an output that we perceive as pain.  Ever heard of a soldier being shot and not feeling any pain until they were safe and out of harms way?  If pain was some absolute thing that the brain has no choice to recognize than you would have no way but to feel pain any time a tissue was injured.  We've all heard stories of people being injured but feeling nothing.

2. Your body does not have to be injured to feel pain.  In fact you can lose a limb and later feel pain in that limb that no longer exists.

3. Tissue injuries (e.g. disc bulges, rotator cuff tears, tendinopathy) do not have to hurt.  The body can have lots of so called "dysfunction" but this does not mean that you will feel pain.  For example, 50% of people over fifty may have a rotator cuff tear but they experience no pain.

4. Emotions, beliefs, stress, past experiences etc can influence the pain that you feel.  Pain is more than a punch in the arm.

5. The perception of pain can move around in your body and this does not mean that you are crazy.  This is a normal finding when we experience persistent pain.

6. Pain changes how we move and how we function.  Movement is often the key to resolving pain.

There is so much more than this but I will let the resources below provide better information.

Books

1. The sensitive nervous system (D Butler):  a great academic reference

2. Explain Pain (Butler and Moseley): a patient's guide to pain

3. Painful Yarns: stories from people with pain

Websites

1. Neurotopian:  Pain for Dummies   a great site, you can read this and ignore everything I say.

 

Youtube

1. Persistent pain described with pictures

http://youtu.be/4b8oB757DKc

 

2. Lorimer Moseley: Tedx Talks

http://youtu.be/gwd-wLdIHjs

 3. Peter O'Sullivan explains how our fears and beliefs about our backs change how we move and contribute to the feeling of pain. 

http://www.youtube.com/watch?v=j4gmtpdwmrs&feature=share&list=ULj4gmtpdwmrs

 

 

All the best,

 

Greg

 

Running Biomechanics Introduction - Differences in range of motion with running and increasing speed

Audience: RunnersPurpose: To give a pictorial basic background into the movements that occur in the sagital plane (i.e. looking from the side) of the lower extremity during running at 3.1 meters/second (about a 5 minute km) and "sprinting" at 3.9 meters per second (about a 4.17 minute km). 

Sprinting is the dotted line in the graphs below.

Source: The following graphs have been adapted from Novachek (1998).  It should be noted that there is some variability between studies.

I would note that there is certainly some other research suggesting that hip extension does not increase with running speed (or even when going from walking to running). While it may look like the upper thigh is bent further back when watching someone the actually movement is coming from an increase in the anterior pelvic tilt of the runner rather than from the hip extending backwards.

View these graphs as a schematic representation and understand that there is some differences across people.

If you like numbers:  The knee is flexed about 25 degrees when the foot hits the ground, will flex an additional 20 or so degrees while it bends, it will then straighten to about 10-15 degrees shy of being completely straight and then it will bend more than 70 degrees when you swing it through.

While the above graphs show the general trend for changes from running to faster running (albeit with some debatable hip function) the graph below brings together all three movements of the hip, knee and ankle.  This graphs has been adapted from the work of Jay Dicharry at the UVA lab.

The UVA lab is the same research group demonstrating how hip extension is not increased during running and how anterior pelvic tilt contributes to the thigh looking like it is further extended.

An interesting tidbit...

In a cool study (Leskinen et al 2009) comparing elite 1500 metre runners with national standard runners (still fast) and running the same speed a group of researchers found differences in their running kinematics.    The authors found that the elite runners did not flex their knees as much during landing (i.e. stiffer knees) and that these runners flexed their hips faster.

Stay tuned for more posts going into further detail on running mechanics.

Your Toronto Physiotherapy source,

Greg

Barefoot, forefoot strike and heel strike - a biomechanics summary

Audience: Runners and therapistsPurpose: To summarize the biomechanics of running strike pattern and shod conditions

I feel like in the blogosphere and the popular running media that there is a love affair with all things barefoot.  Barefoot running is associated with forefoot striking and there appears to be changes in the biomechanics associated with alteration in running form when compared with heel striking.  However, the research gets presented as if it is very neat in tidy when in fact it is quite murky.  This post is a work in progress.  It attempts to summarize some of the work comparing barefoot running with shod running and the work that compares forefoot striking and rearfoot striking while running in shoes.  I hope that I have conveyed that the results are quite conflicting.  Hence, what a pain it was to try to summarize this work.

This post will be updated consistently. Please view it as a work in progress.

A. Changes when going from shod to barefoot running

Kinematic changes

-there is a trend to shift  from rearfoot striking to landing more on the midfoot or forefoot

-an increase in step frequency (e.g. more steps per minute)

-a decrease in step length (Divert et al 2008, Squadrone 2009)

-the foot is more plantar flexed (i.e. the toes point down at contact) and there is a greater degree of ankle motion (Pohl and Buckley 2007, Lieberman et al 2010)

-a decrease in the amount of peak pronation or calcaneal eversion (Morley et al 2010) which is most evident in runners who pronate a great deal.  Going barefoot decreases peak eversion from 10.3 degrees to 6.7 degrees in moderate pronators and from 14.8 degrees to 9.2 degrees in super pronators.

-the time it takes to get to maximal calcaneal eversion decreases in barefoot

-total eversion distance is increased with barefoot running.  Even though there is less pronation the foot starts in a greater degree of inversion when barefoot.  Therefore, the heel travels a greater distance when striking the ground to reach maximal eversion/pronation.

Force or Impact changes

-a decrease or complete reduction in the impact peak (aka. impact transient) when the foot strikes the ground but the push off peak is unchanged. A shod heel strike vertical ground reaction force can be seen in this video from Dr. Lieberman:

http://www.youtube.com/watch?v=zavoQM3727s&feature=player_embedded

In the following graph notice how the first "bump" is lower in the barefoot and forefoot condition when compared with the rear foot shod condition (Divert 2008).

Ummm, is the initial impact transient eliminated with Barefoot running?

The initial impact transient is not always eliminated with barefoot running. While, other researchers (Lieberman 2010) show that the initial impact peak or impact transient is completely washed out rather than just decreased this is not always seen. Dr Lieberman's work is fantastic and his argument is beautifully laid out.  His website is here (http://www.barefootrunning.fas.harvard.edu/4BiomechanicsofFootStrike.html)

He also provides this video showing the impact transient loss when running barefoot and forefoot striking.

http://www.youtube.com/watch?v=TjrEyfQC5NQ&feature=player_embedded

In the study by Divert (2008)  three out of the 12 subjects continued to demonstrate an impact transient. This difference may be due to the fact that other studies investigate youths who have always run barefoot while in the above graph (from Divert 2008)  the subjects were just learning to run barefoot and may have not run a sufficient number of steps for the body to adapt and modify its kinematics.   In effect, the sample used in the above study may have  not had enough time to learn how to run barefoot to eliminate that impact peak.

Nonetheless, below is a graphic by Dr. Lieberman showing the loss of the impact transient with barefoot forefoot striking

In contrast to Dr. Lieberman's work, other studies have also looked at habitually barefoot runners and have NOT found a complete loss of the impact peak, albeit a reduction was found when running barefoot or in Vibrams versus a standard shoe. Squadrone (2009) compared barefoot, shod and Vibram wearing runners in athletes who have had extensive experience running barefoot (3 of them having completed a marathon barefoot).  In the following graph notice how the impact transient is still greatest with shoes, decreases with barefoot and is most modified with Vibrams (VF).  Most importantly, notice how the impact transient still exists.  These authors did not calculate the slope of this impact transient so it can not be directly compared with the work of Lieberman et al (2010).

How can this impact transient still exist in minimalist or barefoot runners?

One difference between Lieberman's group and Squadrone's group may be the degree of plantar flexion in the ankle that occurs at footstrike in both groups.  In Squadrone's group the ankle is at 94 degrees - this means about 4 degrees of plantar flexion.  In Lieberman's group the plantar flexion in habitually barefoot Kenyan youths is around 14 degrees.

This is an important point which leads to a main thesis of this article.  It implies that barefoot or minimalist running alone is NOT A SUFFICIENT condition to obliterate your impact transient during foot strike.  In fact, if you run barefoot in a heel to toe fashion you will see an increase in the impact transient.  This was seen in the work by De Clercq (2000) who compared barefoot versus shod but made everybody still run with a heel strike.  This was found a decade later by Dr Lieberman.  De Clerq found this:

Not to be too confusing but the above authors also measured foot dorsiflexion at impact and found an ankle angle of around 94 degrees (4 degrees of plantarflexion) with a sole angle around 12 degrees (I believe the sole angle is the angle of the entire foot relative to the flat ground).  Zero degrees would be flat while 12 degrees means the toes are pointing up relative to the ground (this is my interpretation, it was not explained in the article). This ankle angle in the barefoot condition is similar to the Squadrone's study of 94 degrees yet we see an impact transient as well as a greater rate of force development in the barefoot condition.  My interpretation here is that while the ankle was slightly plantarflexed the heel still came down first (i.e. the sole angle was still pointing up).  I don't know what the sole angle was in the Squadrone study but it  certainly might help explain the difference between studies.

Bottom line about barefoot.

Obviously barefoot running is no panacea for eliminating an impact transient.  Additionally, there are other factors associated with barefoot running (e.g Kinematic variables: stride rate, stride length, ankle range of dorsiflexion, range of pronation) that may influence many of the kinetic variables (e.g. impact transient, ground reaction forces).  And most importantly how does it relate to injury and performance?

So lets look at these other variables.  Very simply, barefoot running seems to shift someone from being a Heel striker to being a forefoot striker.  A small amount of research has investigated the differences while running in shoes with a rearfoot versus a forefoot strike pattern.

Can changing your foot position at foot strike influence Kinematics and Kinetics?

They sure can, please read more.  Dr Irene Davis has been involved in much of this research but there is surprisingly little published.  Dr. Davis' published work often cites her unpublished lab findings when comparing a Rearfoot strike (RFS) with a forefoot strike (FFS).  Some of what I cite below will refer to Dr. Davis' statements (Williams et al 2000 or Laughton et al 2003)  in her introduction or discussion instead of her actual data (which I can not get a hold of).

Kinematic and Kinetic Changes when moving from a rearfoot to forefoot strike

Kinematics

- forefoot strikers have increased calcaneal eversion excursions and eversion velocity (McClay and Manal 1995a/b) but end up with less maximal calcaneal eversion (aka pronation)

- the foot lands with greater ankle plantar flexion and is in greater inversion at foot strike in the Forefoot strike condition.

--increased knee internal rotation velocity in Forefoot strike conditions (Williams et al 2000)

Changes in Leg Stiffness

-According to the work of Laughton et al (2003) forefoot strikers have greater leg stiffness in general but less ankle stiffness.  They have less ankle stiffness because there is more time and range of motion for the ankle to bend. Essentially, there is more time for the ankle to spread out the joint torque during impact because the ankle moves a through a larger range with the forefoot strike (remember, the foot contacts the ground with the toes down in plantar flexion) (Laughton et al 2003).  These authors also found that the knee does not flex as much in the forefoot strike condition as in the rearfoot strike conditions (30 degrees versus about 34 degrees) therefore there is greater overall leg stiffness.

-Conversely, according to the work of Lieberman et al (2010) forefoot strikers have greater leg compliance (defined as the drop in the body’s centre of mass relative to the vertical force during the period of impact) meaning there is also greater Knee flexion as well as ankle flexion when striking with the forefoot.

Inconsistent changes in Impact Force with forefoot strike

Dr Lieberman's website has an excellent video that shows modifications in the impact transient when striking with a forefoot in shoes.  Unfortunately, this kinetic information is not accompanied with a great deal of kinematic information.

Dr Lieberman has shown the loss of the impact transient in the following video:

http://www.youtube.com/watch?v=XO4MruQov4Q&feature=player_embedded

However despite this decrease in the impact transient documented in the video  the one other study that investigated Shod running and changes in foot strike pattern show different results.

A review of Laughton et al (2003)

These authors compared rearfoot and forefoot strikers ground reaction forces and found the following:

-There is less peak tibial positive acceleration in the rearfoot strike condition

-The average peak vertical ground reaction force, the anteroposterior peak GRF (i.e. the braking force),and average anteroposterior GRF load rates were significantly greater for the FFS pattern than for the RFS pattern

-Average and instantaneous vertical GRF load rate (i.e. the impact transient), however, did not differ significantly between the FFS and RFS patterns.

-BUT...in the Laughton study the forefoot striking runners were different than your typical forefoot strikers.  You might actually call the TOE runners because when their forefoot struck the ground they were not allowed to let their heel strike the ground.  This is not what happens with barefoot/forefoot running.  This may account for the differences in loading.

Is this getting CONFUSING?

What I take from this is that forefoot striking can certainly decrease the loading rates on the foot/shank to a similar extent as barefoot running.  But again, it is not a SUFFICIENT condition.  I would guess that it might even be possible to train yourself to run with a heelstrike but in such a manner that you decrease your impact transient.  Work out of Dr. Davis' lab that gives feedback to individuals on their tibial shock shoes that people can learn to run softer and decrease the impact transient. In these studies (click here) no advice is given to forefoot strike and individuals wear neutral shoes.  They are merely asked to run softer and are given feedback.

I don't have a definitive answer for why the Laughton study shows no change in the impact transient yet Lieberman's work shows a significant decrease in the loss of the impact transient.  My hunch is that other kinematic variables may influence the loading through the foot.   One explanation may be that if in the Laughton study there was no difference in the stride length when shifting to a forefoot strike from heel strike then this may account for the lack of a loss of the impact transient (couple this with the lack of the heel being allowed to lower to the ground - a type of impact absorption and this may explain our differences).

What is missing in this review

- research investigating whether individuals could wear standard running shoes yet still be trained to run in a manner that mimics all of the kinematics of barefoot, forefoot strike running.

-any research investigating the theory (I stress theory) that running in shoes influences plantar foot proprioception which in turn negatively influences running - this belief is very common and is always written about in a superficial  manner.  Yet there is not a lot of research investigating it.  I will reserve an opinion.

-a full body kinetic analysis comparing all the different foot conditions of running.

-long term studies investigating changing stride mechanics on injury prevalence and running efficiency

-I purposefully left out the good research investigating the POSE technique

Clinical Relevance - What I tell my patients

I think it is too early to give barefoot running the gold medal and switch everyone to minimalist shoes but I am certainly open to the idea.  Runners were still getting injured with minimalist shoes in the 1970s (see a pdf review here: Am J Sports Med-1978-James-40-50 running injury overview from 1978 surprisingly good we know nothing new)

Barefoot or forefoot strike running may be an excellent adjunct to the recreational runner as a training stimulus.  It can be used as a form of strength training or rehabilitation.

No research has looked at the impact transients with runners who run much slower than what is studied in these papers.  Most of these papers have the slowest runners running 5 minute kilometres (an 8 minute mile).  The vast majority of your recreational runners do not run this pace.  If you run at 25 minute 5 km you will probably be in the top 10% of a large race (for example, at the 2010 Goodlife Marathon 5 km a 25 minute result put you 178th out of 2721) and the top 15% if you keep that pace up for a marathon.  So, do we want to be telling all our runners to covert to a forefoot strike, minimalist shoe or barefoot based on the research of relative elites? the only correct :) answer is -----I have no idea.

Good luck piecing this all together and stay tuned for more updates.

Greg Lehman

Toronto Physiotherapist

References

Squadrone R, Gallozzi C. Biomechanical and physiological comparison of barefoot and two shod conditions in experienced barefoot runners. J Sports Med Phys Fitness. 2009 Mar;49(1):6-13.

Divert C, Mornieux G, Freychat P, Baly L, Mayer F, Belli A. Barefoot-shod running differences: shoe or mass effect? Int J Sports Med. 2008 Jun;29(6):512-8. Epub 2007 Nov 16.

Pohl MB, Buckley JG.Changes in foot and shank coupling due to alterations in foot strike pattern during running.Clin Biomech (Bristol, Avon). 2008 Mar;23(3):334-41. Epub 2007 Nov 19.

Morley JB, Decker LM, Dierks T, Blanke D, French JA, Stergiou N. Effects of varying amounts of pronation on the mediolateral ground reaction forces during barefoot versus shod running. J Appl Biomech. 2010 May;26(2):205-14.

Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D'Andrea S, Davis IS, Mang'eni RO, Pitsiladis Y.Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature. 2010 Jan 28;463(7280):531-5.

Carrie A. Laughton1, Irene McClay Davis2, and Joseph Hamill Effect of Strike Pattern and Orthotic Intervention on Tibial Shock During Running JOURNAL OF APPLIED BIOMECHANICS, 2003, 19, 153-168

Williams DS, McClay IS & Manal K: Lower extremity mechanics in runners with converted forefoot strike pattern. Journal of Applied Biomechanics, 16(2): 210-218, 2000.

McClay, I., & Manal, K. (1995a). Lower extremity kinematic comparisons between forefootand rearfoot strikers. In K.R. Williams (Ed.), Conference Proceedings: 19t Annual Meeting of the ASB, Stanford, CA (pp. 211-212). Davis, CA: UC–Davis.

McClay, I., & Manal, K. (1995b). Lower extremity kinetic comparisons between forefootand rearfoot strikers. In K.R. Williams (Ed.), Conference Proceedings: 19th Annual Meeting of the ASB, Stanford, CA (pp. 213-214). Davis, CA: UC–Davis.