exercise

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.

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.

Shoulder Rehabilitation: Minimizing the Upper Trapezius to Serratus Anterior Ratio

Audience: Therapists

Purpose: I like the idea of quantifying the "dosage" of an exercise.  We can do this with EMG and this post will be part of a larger theme that catalogues the EMG amplitude of various shoulder rehabilitation exercises.  Further, it will also try to justify a number of exercises for their ability to avoid negative loading on the shoulder and promote a possibly optimal way of working the shoulder.

Caveat:  This review only looks at a few papers addressing the Upper Traps (UT) to Serratus Anterior (SA) ratio.  Other exercises must obviously be incorporated into a rehab program.

Exercises to maximize the Serratus Anterior (SA) to Upper Trapezius (UT) Ratio

To simplify: SA = good, UT = bad.  Basically, activation of the SA moves the scapula out of the way of the humerus while too much or too early activation of the UT tends to

anteriorly tilt the scapula and decrease the space for humeral movement.  Ann Cools has done extensive work in this area.  Here is a taste of her findings and recommendations.  You may want to consider using the exercises when you have a little scapular dyskinesis on your hands - you may see some medial border prominence of the scap, some winging during arm elevation and the scap can get a little jiggy with arm raising and lowering.

Three exercises were selected as exercises with a low UT/LT ratio:

  • side-lying external rotation,
  • side-lying forward flexion, and
  • prone horizontal abduction with external rotation.

Three exercises were selected for minimizing the UT/LT ratio:

  • side-lying forward flexion
  • side-lying external rotation and
  • horizontal abduction with external rotation

The authors conclude that no exercise satisfied their criteria for optimally minimizing the UT:SA Ratio.  But honourable mention was given to forward flexion and scaption with External Rotation.  We therefore have to look to other research to find the best exercise for this ratio - that exercise would be the Push Up Plus which demonstrates a ratio less than 20% for the "plus" portion of the push up and less than 50% for the push up portion of the push up.  Serratus Anterior activity waltzes in at more than 120% for the plus portion and greater than 80% for the push up portion.  Upper trap activity is between 20% for the push up portion and around 9% for the plus phase.  See Ludewig (2004) for the full paper

Some Raw Data

I have bastardized a table from the Supplementary Data of the Ann Cools article.  The following table shows the EMG activity (expressed as a percent of maximum for the Lower Traps, Middle Traps, Upper Traps and Serratus Anterior).  For simplicity I have only included the isometric portion of the exercise. The original article also looked at the concentric and eccentric phases.  Also in the chart is the Ratio of the above musculature to the Upper Trapezius.  Remember, the ideal is be lower.  Suggesting less Upper Trap activity and more of something else.

Table 1: EMG and Ratio Activity during various Rehab exercises (modified from Cools et al 2007)

EMG - % of MVC* Ratios
Exercise UT MT LT SA UT/LT UT/MT UT/SA
Prone shoulder abduction 50 78.4 76.7 14 75 71 597
Forward flexion 38 26.5 29.5 95.2 250 236 53
Forward flexion in side-lying position 8.6 35.5 63.7 34 16 27 50
High row 7.3 17.3 17.5 28.6 62 51 50
Horizontal abduction 33.7 63.8 50.3 17.3 77 60 339
Horizontal abduction with external rotation 43.7 78.2 79.2 15.5 65 65 467
Low row (1) 19.5 30.4 26.2 35.1 120 76 108
Low row (2) 21.6 31.9 20.3 19.9 162 77 206
Prone extension 15.9 30.1 30.9 34.7 82 62 84
Rowing in sitting 31.4 41.6 29.8 12.1 122 105 458
Scaption with external rotation 44.9 31.7 32.3 101.7 273 246 51
Side-lying external rotation 5.54 18.2 51.1 9.8 14 39 92

The next table describes all of the exercises.

Table 2: Exercise Description

Exercise Description
Prone shoulder abduction Subject prone with the shoulder in neutral position; subject performs shoulder abduction abduction to 90° with external rotation in a horizontal plane
Forward flexion Subject standing with shoulder in neutral position; subject performs maximal forward flexion in a sagittal plane
Forward flexion in side-lying position Subject in side-lying position, shoulder in neutral position; subject performs forward side-lying position flexion in a horizontal plane to 135°
High row Subject standing in front of vertical pulley apparatus with the shoulders in135° forward flexion; subject performs an extension with the shoulders until neutral
Horizontal abduction Subject prone with the shoulders resting in 90° forward flexion; subject performs horizontal abduction to horizontal position
Horizontal abduction with external rotation Subject prone with the shoulders resting in 90° forward flexion; subject performs horizontal abduction to horizontal position, with an additional external rotation of the shoulder
Low row (1) Subject standing in front of pulley apparatus, shoulders in 45° forward flexion an
Low row (2) Subject standing in front of pulley apparatus, shoulders in 45° forward flexion and neutral rotation; subject performs extension with the elbows flexed
Prone extension Subject prone with the shoulders resting in 90° forward flexion; subject performs extension to neutral position with the shoulder in neutral rotational
Rowing in sitting Subject sitting in front of pulley apparatus with the shoulders in 90° forward flexion;position with 2 handles subject performs an extension movement with the elbows flexed and in the horizontal
Scaption with external rotation Subject sitting with the arms at the side; subject performs maximal elevation of the arms rotation in the plane of the scapula (30° anterior of the frontal plane)
Side-lying external rotation Subject side-lying with the shoulder in neutral position and the elbow flexed 90°; subject rotation performs external rotation of the shoulder (with towel between trunk and elbow to avoid compensatory movements)

WHY IS THIS RELEVANT?

I think this paper tells us that these are not the exercises that we should be doing if we think that the ratio between UT and the SA is the biggest problem. When we look at the EMG values and not just the ratios we can see that few of the exercises investigated appropriately challenge the SA with the exception of Forward Flexion and Scaption.  Fortunately, they also have relatively good UT:SA ratios (please note, when performed dynamically the ratio is higher, in other words worse for the shoulder).   If we look at previous research by Paula Ludewig who investigated Push Up Plus variations we learn that sticking with the Push Up Plus is still the ideal exercise to train the SA while minimizing Upper Traps.

Do Push Up Plus Exercises for the best UT:SA Ratio

As for the push up plus and its varations (Standard Push Up Plus (SPP), Knee Pushup Plus (KPP) and Wall Pushup Plus) look at the Serratus EMG activity and the associated ratios in the following modified charts.

The chart to the left shows eccentric (blue) and concentric (red) EMG activity during the non "plus" portion of the push up plus.  The "plus" portion is 20-40% MVC higher.  This graph shows that the Push Up Plus activates the Serratus between 40-80% of its maximum (depending on type of movement).  The Plus portion achieves values close to 120% of maximum.  Kneeling push up plus (KPP) and Wall Pushup Plus (WPP) tend to have less activity.

When we look at the Upper Trapezius to Serratus Anterior ratio we find the lowest ratios occur with the Standard Push Up Plus.  Showing less than 50% for both concentric and eccentric portions of the push up  activity (non plus phase) and less than 20% ratio during the "plus" phases of the activity (not in the chart) as I wanted to show the worst case scenario.   Note how the wall push up starts to have a lot more Trap activity and therefore it throws the UT:SA ratio way to high for it to be ideal.  Upper trap activity typically reaches between 15 and 25% during the eccentric portion of the pushup and between 6-12% during the eccentric portion of the "plus" phase of the push up plus.

Bottom Line:  The standard push up and standard push up plus demonstrate the highest levels of Serratus Anterior EMG activation as well as the lowest ratio the UT:SA activity. The wall push up plus should be avoided and it may even lead to impingement.

Further References

Reinold MM, Escamilla RF, Wilk KE. Current concepts in the scientific and clinical rationale behind exercises for glenohumeral and scapulothoracic musculature. J Orthop Sports Phys Ther. 2009 Feb;39(2):105-17. Review.

Kibler WB, Ludewig PM, McClure P, Uhl TL, Sciascia A.Scapular Summit 2009: introduction. July 16, 2009, Lexington, Kentucky. J Orthop Sports Phys Ther. 2009 Nov;39(11):A1-A13. Review.

Escamilla RF, Yamashiro K, Paulos L, Andrews JR.Shoulder muscle activity and function in common shoulder rehabilitation exercises. Sports Med. 2009;39(8):663-85. Review.

Ludewig PM, Hoff MS, Osowski EE, Meschke SA, Rundquist PJ Relative balance of serratus anterior and upper trapezius muscle activity during push-up exercises. Am J Sports Med. 2004 Mar;32(2):484-93

Cools AM, Dewitte V, Lanszweert F, Notebaert D, Roets A, Soetens B, Cagnie B, Witvrouw EE.Rehabilitation of scapular muscle balance: which exercises to prescribe? Am J Sports Med. 2007 Oct;35(10):1744-51. Epub 2007 Jul 2.

Raw Data

Patellofemoral pain syndrome exercise sheet

Attached is a basic exercise protocol as part of a large physiotherapy regime I might use for someone with some lower extremity dysfunction.  Many of these exercises would be used for non specific knee pain (PFPS, ITB syndrome).  The nordic hamstring exercise could be skipped but should certainly be used for anyone with posterior chain weakness/dysfunction.  I use that ol' nebulous word 'dysfunction' when something is wrong (e.g. pain) but I'm not willing to commit to some BS therapist jargon about the cause of the problem.  You could put in the same room 5 great therapists (physiotherapists, chiropractors, massage therapists, sport med docs) who could all get someone better but they would each explain the problem completely different and often contradict each other.  So, I use the general word dysfunction. Attached is a two page pdf for primarily knee problems that might have a proximal component.

Does everyone love my beautiful fitness model.  I spend way too much time with her.

Click below for a pdf version of the exercise sheet.

hip and knee dysfunction two day program for le dysfunction

Adios,

Greg Lehman, Physiotherapist & Chiropractor

Why the side lying hip abduction exercise is way overrated.

Audience: Health professionals I used to be a researcher (exercise biomechanics, physiotherapy,  chiropractic) - one of my goals was to quantify how hard muscles worked during different exercises.  This was important for determining which exercises may be best for targeting a certain muscle or determining how modifications to exercises (e.g. doing it barefoot or on a wobbly surface - for a simple paper look here) changed the targeted muscles response.

I used surface EMG which quantifies the electrical activity of that portion of a muscle that was under the electrodes.  Surface EMG is messy and you are required to process the crap out of it to get something meaningful. 

The problem is that you can't just say that because there is 56 volts (this is an arbitrary unit you might as well say 56 bananas) of activity in the vastus lateralis in Mary and 24 volts in Mary's vastus medialis that Mary is somehow deficient in her VM muscle.  But people do this and they are wrong.  Don't get me started on the chiropractors that use surface EMG scans of people's backs to tell them they are dysfunctional - that is a lot of poppycock.

What also happens is the huge amount of variability across people and within people in EMG readings that is not related to how active a muscle truly is. This means that just because a muscle looks like it works very hard (i.e. lots of EMG activity) in many people does not mean it works that hard in everyone.  Further, there is a lot of variability across people in how they respond to different exercises - we have to be careful in how we generalize research to different patients. For example, tall guys with short torsos get very little abdominal challenges with modified curl ups (I had a subject with less than 15% of max whereas others would have 40-60% of max).

A specific example EMG Research that you may want to question

A big problem with applying and interpreting surface EMG is the lack of a reader's and researcher's healthy skepticism.  I will now pick on a paper that has always bothered me.  This study was published in the JOSPT by DiStefano (2009).  The paper looks good, I love the concept and the execution, the methods look totally appropriate but it does not make any sense. 

The authors aimed to determine what was the best exercise to activate the Gluteus Medius. This is an important muscle for spine and hip stability and is often implicated as problematic for Runners. Groups of physiotherapists have been touting its importance for years.  But what the authors concluded does not make sense nor fit with any research before them.

Brief Paper Findings and my perceived flaw

The authors found that the best exercise to activate the hip abductors was the side lying leg raise (hip abduction).  They found that the average  muscle activity was 82 % (Standard Deviation = 42) of the subjects maximum.  This is crazy.  I have nothing against the sidelying leg raise but it does not recruit your hip abductors to more than 82% of your max.  And the standard deviation was 42, suggesting that some people were over or near their maximal ability.  Yet somehow they completed 8 repetitions.  That in and of itself is a huge give away that your hip EMG stinks.  Something is wrong if your EMG process tells you someone is working close to near maximum yet they can do 8 repetitions.  That is a big red flag.  Yet this paper got published, someone got a PhD and there was no mention of this simple possibility.

Further, previous papers by Ekstrom et al (2007) and Bolgla and Uhl (2005) investigated the exact same muscle during the same exercise.  These two different research groups found muscle activity between 39 and 42% of maximal activity.  No mention was made in the discussion of these two other papers explaining why the 20 or so subjects had muscle activity nearly twice what others had found.

Take home point

This looked like a very well designed study.  It just made no sense from what others had previously found and what our senses tell us about how hard an exercise feels (do a leg raise on your side - its not that hard).   This finding should certainly warn us about the limitations of research and that you certainly should not believe or accept what is published.

Adios,

Greg

Jewels from Juker (1998). Insight into the Psoas Part One

Stu McGill was an author on this paper when it came out back in 1998.  At the time, I was one of Stu’s grad students putting electrodes onto anyone I could find for the price of Gyro sandwich.  I even burned (chemically and transiently) the thigh of a girlfriend at the time.  I knew how to treat the ladies.  Unfortunately, I never really picked Stu’s brain about this paper.  It was only relevant to me at the time because we were strongly questioning the necessity of double leg lifts as an exercise for the "lower abs".  We felt they were unnecessary to recruit the lower abs and too costly because of the compressive and anterior shear component applied to the lumbar spine. Our argument was that there is no difference between the upper section of the rectus abdominis and the lower section.  I still stand by it and the paper is here ( http://ptjournal.apta.org/content/81/5/1096.full ). Regardless of my youthful oversight, I still love the paper and the ideas of sticking needles into the psoas.  It must feel awesome hence the “n” of only 5. Below are a few tidbits that will lead into future posts on psoas function. 1. the psoas was only minimally active (less than 5% of maximum) during a squat lift and while lifting 40 kg pails in both hands.  This suggests that during these tasks the psoas has a very negligible role for both stability demands and creating the primary movement.  This finding certainly questions the psoas importance as a stabilizer of the lumbar spine.  Although, part of Paul Hodges' research cabal recently put out a good paper (as usual) that showed that the psoas fired bilaterally (the only hip flexor muscle to do so) during an Active Straight Leg Raise (one leg only).  Again, suggesting its importance for stability.

2. the psoas was most active while standing with the hip flexed 90 degrees while a maximal force is applied against the knee in an attempt to extend the hip.  The psoas reached 100% max activity.  When the same action occurs while lying on ones back the average activity drops to approximately 57%.  This is cool although certainly not revolutionary to most.  It suggests that the psoas is not only working to flex the hip but to keep pelvis level – the psoas is working to create an ipsilateral lateral bending moment about the lumbar spine to help the contralateral hip abductors and probably the ipsilateral QL.

3.The limits of reciprocal innervation.  It is commonly stated that to inhibit one muscle we must activate its antagonist, aka. Sherrington’s law of reciprocal innervation.  In my opinion this is a pretty overused “law” in the Kinesiology field.  It is thrown around to justify treatments or explain dysfunction with really minimal if any research support.  The Juker paper took a look a the notion that the psoas could be inhibited during the sit up if the  hamstrings (a psoas antagonist) were activated. This hypothesis was not supported by Juker’s results, and in fact psoas activity was increased (28 % and 34 % MVC for the press heels style of situp) compared with that during bent knee sit-ups (17% and 28% MVC)

Big mouth comment:  Does the “law” of reciprocal innervation only apply when it is expedient.  We use it to justify PNF stretching, the “active” component of ART and to explain that a “tight or spasming” muscle is constantly inhibiting another muscle.  Yet, we ignore this law’s power during common activities.  Co-contraction of both agonists and antagonists is fundamental to stability and many movements (e.g. both the hamstrings and quadriceps fire simultaneously during running or squating – Lombard’s paradox. See link http://en.wikipedia.org/wiki/Lombard%27s_Paradox).  I would really like to know what a real neurophysiologist says about this. I have always been  under the impression that reciprocal innervation/inhibition functioned at a reflexive level rather than at the voluntary activation level.

Part Two of this post will look at other “old” research that investigates Psoas function with questions about our clinical insights.

Super Jem of a Reference

Juker D, McGill S, Kropf P, Steffen T. Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks. Med Sci Sports Exerc. 1998 Feb;30(2):301-10