Skeletal muscle in running.

Footnotes 7 - White and Red.jpg

"skeletal muscle may provide a fundamentally different mechanical function during running than during activities such as swimming,flying, or jumping. These activities require muscle contractions that produce mechanical work at high rates to overcome drag,produce lift, or accelerate the body. Because running requires negligible work against drag and the average mechanical energy of the body is constant over time (at a steady speed on level ground), the demands of support may be met most economically by muscles that produce force while minimizing mechanical work."- Roberts et al


Muscular Force in Running Turkeys:
The Economy of Minimizing Work
Thomas J. Roberts,* Richard L. Marsh, Peter G. Weyand,
C. Richard Taylor

Is swinging the arms worth it ? The metabolic cost of running.

The metabolic cost of human running: is swinging the arms worth it?
(precursor: *photo depicts a nice wide antiphasic gait, when that narrows, possibly for spine protection, limb swing becomes more phasic. In these senarios, forcing more arm swing action in a runner is foolish. One is not likely smarter than their client's body's protective mechanisms, so one needs to stop forcing things when they don't know what they are dealing with).

There remains scant info regarding the metabolic benefit of arm swing during human running. We have written about arm swing many times in the past, the concepts of phasic and antiphasic upper and lower limb swing (and their impact on spine loading) are critical for one to understand if they are working with runners. Without the understanding of these principles, coaching runners on form change adds risk to the plate of your client. Feel free to search our blog on these topic. But while you read on, please keep in mind all those strange unilateral compensatory arm swing things you see, such as an abducted arm on one side, a circumducting arm, one arm swinging more than the other, or less than the other, sports where we are carrying something (ie. a football) or throwing (ie javelin), or running with a water bottle. And please consider going back and re-reading all of our arm swing posts discussing why coaching a different arm swing, certainly a corrective arm swing, might be a bad idea because it could be a compensation from the lower limbs since the arms are positioned to be such good postural ballasts.

Here Arellano & Kram "compared the metabolic cost of running using normal arm swing with the metabolic cost of running while restricting the arms in three different ways: (1) holding the hands with the arms behind the back in a relaxed position (BACK), (2) holding the arms across the chest (CHEST) and (3) holding the hands on top of the head (HEAD)."

They hypothesized that "running without arm swing would demand a greater metabolic cost than running with arm swing." What the found in comparing with running using normal arm swing, a net metabolic power demand was 3, 9 and 13% greater for the BACK, CHEST and HEAD conditions, respectively (all P<0.05).

They also discovered that "when running without arm swing, subjects significantly increased the peak-to-peak amplitudes of both shoulder and pelvis rotation about the vertical axis, most likely a compensatory strategy to counterbalance the rotational angular momentum of the swinging legs."
In conclusion, Arellano and Kram's findings "support a general hypothesis that swinging the arms reduces the metabolic cost of human running". Their findings also "demonstrate that arm swing minimizes torso rotation". We infer that actively swinging the arms provides both metabolic and biomechanical benefits during human running. (Our big question is, when said clients come in for an upper quarter limb problem , is it because they may have been coached to actively swing the arms, or swing them differently?). Those who coach arm swing changes without a physical examination to determine why one arm has an aberrant swing may be driving new compensations onto old compensations, which could very well be the source of the problem.

Important: this study likely did not look at the aberrant arm swing habits that develop when there is a lower limb mechanical aberrancy. The literature has suggested that arm swing motor patterns are subservient to the leg swing motor patterns, and so coaching arm swing changes seems a bit foolish if the literature is in fact correct. Also, this study does seem to mention asymmetries in arm swing, and how these, though when different may change metabolic cost, may be necessary because of impairments in the antiphasic relationship of the upper and lower limb action.

J Exp Biol. 2014 Jul 15;217(Pt 14):2456-61. doi: 10.1242/jeb.100420.
The metabolic cost of human running: is swinging the arms worth it? Arellano CJ1, Kram R2.

Arm swing during gait. An energetic cost of locomotion?

"Arm swing during gait has an important role in decreasing energetic cost of locomotion. Several pathologies
may lead to various abnormalities in arm movements during
walking. It may therefore be expected that pathological gait is
energetically more demanding, not only because of the pathology, but also because of affected arm movements."- Meyns et all.

The Gait Guys ponder:
Can forcing what we think is a "better" arm swing pattern in turn be considered generating locomotor pathology? After all, we very well may be forcing a change to that which we see, a visual which we do not like, which was already a fundamental compensation around another locomotor deficit. ???

The how and why of arm swing during human walking
Pieter Meyns a,1, Sjoerd M. Bruijn a,b,1, Jacques Duysens a,c
Gait & Posture 38 (2013) 555–562

Podcast 60: Speeding up at the finish line & Efferent Copy

A. Link to our server:

Direct Download: 

http://traffic.libsyn.com/thegaitguys/pod_60final.mp3

Permalink: 

http://thegaitguys.libsyn.com/podcast-60-speeding-up-at-the-finish-line-efferent-copy

B. iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

______________

Today’s Show notes:

1.  Move Your Body, Grow Your Brain

6. Blog reader: Hey again, I personally compete in this uphill/ downhill running race in 2 months. The slops are really steep(incline/ decline).I’m just looking for some useful tips on running biomechanics, cadence etc. Any hints on what things I should be doing and of course avoid doings that will lead to injury? An international podcast fun!

7. Blog reader:

How does subtalar supination/pronation affect plane deviations farther up the chain, specifically at the pelvis? I was going over some notes and found something saying that increased pronation leads to increased frontal plane motion at the pelvis during gait, and increased sup leads to increased transverse plane motion. However, in this video I was watching, the clinician states that increased sup will lead to increased frontal plane motion. Is this not a contradiction? Can both be true? Thanks
So you do not think arm swing is important huh ?  Read these 2 stats and recalibrate your thinking.  
This was yet another slide from last nights well attended teleseminar. Those that attended learned all of the up to date facts that doctors, traine…

So you do not think arm swing is important huh ?  Read these 2 stats and recalibrate your thinking.  

This was yet another slide from last nights well attended teleseminar. Those that attended learned all of the up to date facts that doctors, trainers, coaches, therapists need to quickly understand what factors to look for when observing someones gait.  Including our favorite, “what you see is not the problem in their gait, rather it is there strategy around the faulty parts, problem or pain.”

If you think that changing arm swing at the local level is not a big deal, just digest the towering facts from this slide.  Arm swing is a big deal ! It is a CPG generated big deal (Central Pattern Generator).  

Sorry we missed you last night.  The teleseminar was recorded and should be up on www.onlinece.com or www.chirocredit.com in a few days for you to enjoy on your own free time (and so are a few dozen of our other lectures !).   

So, if you are coaching or making local-level arm-swing form running or training changes in yourself or your client, you are probably making some big mistakes.  Our lecture brings this all to light for you in one place !

Arm Swing matters…….. more than any of us previously knew !

Shawn and Ivo, The Gait Guys

Usain… Again!!! How good are your powers of observation?

Take a look at this video again. Yes, we have shown it many times before. It is from a 2001 race in Monaco.

These are all incredible athletes. What can we note about the fastest of the fast?

  • Most of them have excellent hip extension (ok, the gent immediately to Usain’s right does not appear to be optimal)
  • the fastest of the pack have a upright head posture with the neck neutral or in slight extension (gents in lanes 1, 3 and 6; notice the head forward posture of the others)
  • minimal heel rebound (see our last post on this here)
  • minimal torso motion (note the increased torso motion  with arm swing of the gents in lanes 1, 3, 4 and 5)
  • symmetrical hip flexion, with the thigh parallel or nearly parallel to the ground in float phase
  • what else?

Watch it a few more times. It took us a while too…

Really, go watch it again…

Did you see it?

Watch the vertical oscillation of the runners. At this level (or any level for that matter), outside of improving biomechanics and neuromechanics, there are really only a few things you can do to run faster. One is to have a faster cadence and another is to have a longer stride length. You can control both, but if not done concurrently, one gets better at the expense of the other.

If your cadence is slower and you try and increase stride length, you increase your vertical oscillation (ie: how much you bounce up and down). Note the handrail at the far side of the track. It makes a convenient marker for vertical oscillation. Watch this bar and watch the video again. Usain and the gent in lane 6 (Nesta Carter) have little vertical oscillation compared to the rest of the pack. Note also the close finish. difficult to say if Usain’s knee or Carters foot crossed 1st. Usiain’s time was 9.88 and Nesta’s 9.90.

Decreased cadence = Increased vertical oscillation = Less horizontal motion = Slower speeds

How about watching this video a few more times and telling us what else is up?

The Gait Guys. We are trying to help you improve your powers of observation while stretching your mind. Are we succeeding? We hope so!

Ivo and Shawn

Pod 43. Achilles problems, Neurology of watching sports, PEDS, hip joint centration.

Pod 43. Achilles problems, Neurology of watching sports, PEDS, hip joint centration, risks of swaddling babies and so much more. Join us today for this great podcast !

A. Link to our server:

http://thegaitguys.libsyn.com/podcast-43-achilles-problems-neurology-of-watching-sports-peds-hip-joint-centration-risks-of-swaddling-babies-and-so-much-more-join-us-today-for-this-great-podcastB.

iTunes link:

https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138

C. Gait Guys online /download store (National Shoe Fit Certification and more !) :

http://store.payloadz.com/results/results.aspx?m=80204

D. other web based Gait Guys lectures:

www.onlinece.com   type in Dr. Waerlop or Dr. Allen,  ”Biomechanics”

________________________________________

* Today’s show notes:

Neuroscience pieces:
1. Brief Exposure to Performance-Enhancing Drugs May Be Permanently ‘Remembered’ by Muscles
 
 Brief exposure to anabolic steroids may have long lasting, possibly permanent, performance-enhancing effects, shows  … .

2- Watching is like doing http://www.theglobeandmail.com/technology/science/go-neurons-go-science-explains-why-it-hurts-to-be-a-leafs-fan-sports-diehards-are-wired-that-way/article15214848/

This summer, Australian researchers at the University of Western Sydney published a study in which volunteers lounged comfortably in reclining chairs and watched a bland video of someone walking and running. The faster the person on the screen ran, the higher the pulse and breathing rates of the spectators rose, along with  … .

3. Economy and rate of carbohydrate oxidation during running with rearfoot and forefoot strike patterns.
4. Radiolab.org    
5. Neuromuscular strategies for lumbopelvic control during frontal and sagittal plane movement challenges differ between people with and without low back pain.
6. Achilles: How Much Energy Does Your Achilles Tendon Store? Stiffer tendons help you run more efficiently, but it’s not clear how.
7. Ivo: blog post on toe extensors, the neuromechanics behind it
8. From onlineCE.com, last weeks course
9. Hip centration principles……. principles of accessory motions
from a blog reader
11 Q: can metatarsalgia be caused by ITband tighness ?
 
12. Disclaimer
13. National Shoe Fit program and our Payloadz store
14. Take a monthly course from us at www.OnlineCe.com
 
15. Blog reader:
Guys I feel a little ridiculous asking this ? considering the amount of time I’ve spent reading your info but here goes: I understand the concept of the foot tripod and it’s importance for stabilization and balance when static or during single leg with eg squats, but when should the tripod be utilized during the normal gait cycle?
16 .From a blog reader:
Hello Gentlemen, I was wondering if you could point me in the right direction in terms of addressing a Tailor’s bunion on the 5th met. Thank you!!

What Does Changing your Stride Cost You?

http://running.competitor.com/2013/09/training/study-changing-running-stride-does-more-harm-than-good_41136

A recent study cited in Competitor Magazine, talked about common stride “improvements” actually may reduce running economy. They looked at stride rate (cadence) and vertical displacement. One would think, with all the hoopla out there, that more steps per minute and less vertical displacement would be more efficient. The actual study concluded “Alterations led to an increase in metabolic cost in most cases, measured as VO2 uptake per minute and kg body mass,” Another study which had similar results can be found here.

Even though the study had a small sample size (16 participants), If you think about this, it makes sense.   Volitional effort usually has a metabolic cost. It does not make it right or wrong; they are just the facts. The nervous system will take time to integrate new (motor) patterns. Each person has a optimal (homestatic) stride “style” which includes vertical displacement as well as stride length, among other factors (lateral sway, ankle dorsi pantar flexion, knee flexion, thigh flexion, etc).

The study itself also concluded ““Mid- and long-term effects of altering … technique should also be studied.” we concur, we have not seen any long term studies that look at economy over time, but would love to read them if any of our readers run across them.

The Gait Guys.  Bringing you the facts without the bling.

Is Barefoot more economical ?

Researchers at England’s Northumbria University analyzed the gait and oxygen uptake of 18 recreational and elite runners performing a series running tasks both barefoot and shod.

Dr. Michael Wilkinson, lead researcher and avid barefoot runner determined the following in their study:

- a significant saving in energy from taking off running shoes

- mechanical differences in the foot strike patterns (shod runners did more heel strike, unshod were more midfoot striking)

- there were immediate foot strike changes in previously shod  runners who suddenly changed to unshod foot strike

- there is less oxygen use during barefoot running compared to running shod at the same speed. Hence improved running economy.

Characteristically, skilled unshod runners have a distinctive running gait utilizing:

- mid-foot landing

- shorter stride lengths

- faster stride rates

- reduced ground contact time

- lower impact force and loading rates which dampens injury inducing forces

- reduced oxygen utilization. The 6% improvement in economy was the same as that previously reported after a nine-week training program for shoe-wearing runners, who also enjoyed a 3% improvement in running performance.

Click on the link above for the Science article.

Are aging runners less economical ?

As the year comes to an end many will begin to think about their future health. Many will start running. Starting is often the hard part, trying to get the old machine working again can take a little time. And as we age, it is not uncommon to get demoralized by the decline of our abilities and performance. This study in the Journal of Strength & Conditioning Research gives hope to us all as we age and for those that are just starting out. Bottom line, it is just going to take a little work.

The study shown below concluded that the runners over 60 were just as economical as even the youngest ones in the study. Oxygen utilization was just a efficient. The obvious problem is that as we age the other parts are not quite as youthful. Muscular strength, muscle mass, tissue elasticity, cartilage pliability etc all reduce and so power output and other parameters reduce.  The good thing is that with sensible training, all areas can be improved which when combined with a system that is still economical into our aging years, we can all still see some pretty bright days ahead of us.  Sure the parts are going to be more apt to breakdown and tolerate less, but even into the golden years, our discussions about training smarter, not harder still hold true.
We have attached the info for the article if you want to find it for your clientele or for your office or gym.                                                                                                                                       
J Strength Cond Res. 2011 Nov;25(11):2971-9.

Aging and factors related to running economy.

Abstract

The purpose of this study was to investigate the relationship that age has on factors affecting running economy (RE) in competitive distance runners. Fifty-one male and female subelite distance runners (Young [Y]: 18-39 years [n = 18]; Master [M]: 40-59 years [n = 22]; and Older [O]: 60-older [n = 11]) were measured for RE, step rate, lactate threshold (LT), VO2max, muscle strength and endurance, flexibility, power, and body composition. An RE test was conducted at 4 different velocities (161, 188, 215, and 241 m·min(-1)), with subjects running for 5 minutes at each velocity. , , , 

Bottom line from the study: The results from this cross-sectional analysis suggest that age-related declines in running performance are associated with declines in maximal and submaximal cardiorespiratory variables and declines in strength and power, not because of declines in running economy.                                                                             

 

Gretchen Reynolds wrote a great article for the NYTimes last week on this topic.  The link to her article is above. “For Older Runners, Good News and Bad.”