Effect of barefoot running on economy and muscle action

There has been a flurry of studies on the effects of foot strike pattern or shoe condition on running economy this year. They are all pretty much showing the same thing. I have blogged about them hereherehereherehere and here, so there is no point litigating old ground again. Two more related studies recently appeared. I can’t say a lot about the two abstracts below as I know nothing more than what is in the abstracts and we will have to await full publication to get all the details. They were presented at the The American College of Sports Medicine Southeast Meeting in September.

NO INFLUENCE OF BAREFOOT RUNNING ON RUNNING ECONOMY
J.T. Repshas, M.M. Koehler, E.E. Hawkins, K.L. Hines and M.G. Flynn.
Barefoot running (BR) has been reported to change running gait and reduce the risk of injury, but few studies have been completed to examine these claims. Proponents of BR claim that running barefoot causes a shift from the heel to a forefoot strike—which improves running economy (RE). Most previous research on BR and RE has used high-level athletes. Therefore, the purpose of this study was to determine if RE differed in recreational runners when running barefoot (BR), running with shoes (SR), or weighted running (WR, foot weights added equal to shoe weight) . The subjects were active male (n=9) and female (n=9) college-aged runners who were training to run in a local 10 km race. Height, weight, body composition (skinfold), and resting blood pressure were recorded and a medical history was completed before testing. Subjects performed three consecutive, seven-minute, randomly assigned, sub-maximal running trials either BR, SR, or WR. Oxygen consumption was measured using a Parvomedics TrueMax 2400 (Sandy, Utah). RPE (Borg 6-20 scale) and heart rate (Polar Heart Rate Monitor) were measured at 5.5 and 6.5 min of each segment. There were no significant differences (p >0.05) in RE (ml/kg/min) among trials. Heart rate and RPE (BR, 12.6 +2.1; SR, 11.9 +2.9; WR, 13.4 +2.8) were not different among trials. Grouping subjects by sex also did not yield any significant differences. We conclude that RE, RPE, and heart rate were not significantly altered by BR in recreational runners who did not have a significant amount of previous experience with running barefoot.

Even though this was an acute intervention in novices, the results are pretty much consistent with what the preponderance of evidence is showing on the issue of running economy in barefoot vs shod.

THE EFFECT OF SHOD VERSUS BAREFOOT RUNNING ON LOWER LIMB MUSCLE ACTIVATION
L. Bauer and C. Inman,
Purpose: Little research has focused on the effect of footwear on lower limb muscle activation. While increased muscle activation may result in increased speed, higher levels of muscle activation during distance walking and running may result in greater muscle fatigue and injury. The purpose of this study is to determine the effects of being shod or barefoot on lower limb muscle activation when walking and running.
Methods: Six college-aged men (n=2) and women (n=4) participated in the protocol (21.4±1yrs, 178.3±8cm, 83.8±26 kg). Average electromyography (EMG) amplitude (mV) over a 15 second measurement period was recorded for the tibialis anterior (TA) , peroneus brevis (PB) , medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SO) and peroneus longus (PL). All EMG activity was recorded, transformed, and reported as root mean square (RMS) activity. Recordings were taken during the last 15 seconds of a single bout of 3 minutes of walking (0.55 m/s) or running (3.6 m/s). Separate trials of barefoot or shod were completed for each speed; all trials were completed on the same day and counterbalanced with 2 minutes recovery between trials.
Results: As expected, running increased muscle activation for all lower limb muscles from walking to running, regardless of being barefoot or shod (p<0.05). When comparing barefoot to shod during walking, there was no significant difference in EMG activity of any muscle (p=0.16 – 0.87). However, EMG activity during barefoot running was reduced in the PL (11%, p=0.04) and tended to be lower in the soleus (23%, p=0.07) when compared to shod running.
Conclusions: Some lower limb muscles show reduced neural activation when running barefoot.

Only 6 subjects, so not going to jump too high about these results but its certainty not a fatal sample size. What was interesting was the reduced EMG activity in barefoot running. EMG is a measure of muscle activity and not strength, but if some muscles are less active during barefoot compared to shod, surely that goes against all the propaganda and rhetoric that barefoot makes the muscles stronger and running shoe weaken muscles? This study would suggest the opposite? Think about it.

As always, I go where the evidence takes me until convinced otherwise, and these studies support the contention that there is no one most economical way to run for everyone and that running shoes do not weaken muscles.

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6 Responses to Effect of barefoot running on economy and muscle action

  1. Barry November 7, 2013 at 2:05 am #

    Hi Craig,

    Another interesting post. Congrats on an excellent site and consistent approach to the evidence btw.

    I wonder if the EMG changes might reflect a longer time to fatigue? Too many other variables to even begin to make an educated guess, I’d posit though. Especially since these assessments seem to have been performed during brief periods of exercise.

    • Craig Payne November 7, 2013 at 2:10 am #

      Thanks. I honestly don’t know. It could be. We really need to see the numbers in the full publication when it happens…. esp on inter-subject variability (I working in a post summarizing why I think we seeing what we are seeing in all the economy studies)

  2. Joe Warne November 9, 2013 at 12:22 pm #

    “Even though this was an acute intervention in novices, the results are pretty much consistent with what the preponderance of evidence is showing on the issue of running economy in barefoot vs shod.”

    Craig, you often talk about “cherry picking” of results to support a statement, but I have started to see a bit of a trend towards supporting conventional shoes in your posts when there is no evidence for such. Here for example with the quote above. When including the mass effect (which was the case in the above study when they compared BF to Shod – exclude the WR condition for now, since no footwear type had any effect), it is very unusual for studies to not find any difference in RE between BF and Shod. We KNOW that extra mass on footwear has a clear effect on RE, so this study that showed no effect is actually quite unusual, and NOT”consistent” with other evidence. Ofcourse we need more information on the footwear being used in this study, since ultra-lightweight footwear may be more economical for a runner than BF, but considering they also included a WR condition to counteract the weight of the shoes, we can assume that this was a regular conventional running shoe that was of significantly higher mass.

    The problem, I find with so much of your reviews, is that you give the impression that people should be attempting to “prove” barefoot running is better than shod. Actually, this is entirely the wrong stance from both yourself and many other researchers, since we should be considering barefoot as the “null” condition, and attempting to document differences or benefits relating to running shod, since this is largely the condition we are “unevolved” for. Ofcourse we dont have the evidence to swing either way yet, but I would make the suggestion that in the few short years that barefoot running science has been underway, there has been a much greater body of evidence than footwear research has produced in the last 40 years.

    • Kevin A. Kirby, DPM July 3, 2014 at 4:14 pm #

      Joe:

      I don’t understand how any objective and intelligent researcher can believe, with nearly no one running barefoot these days and 99.99% of all runners wearing shoes, that “we should be considering barefoot as the null condition”.

      Let’s say, Joe that you knew of other running researchers that were doing a running biomechanics study. Would you tell these researchers that their study was invalid because they wore running clothes during running because you felt that running completely nude was the “null” condition?

      Would you tell researchers that were studying running biomechanics that any study they performed on female runners would be invalid if their subjects wore running bras or that any study they preformed on male runners would be invalid if they wore jock straps or support brief because complete nudity is the “null” condition?

      And as for your contention that running in shoes “is largely the condition we are unevolved for”, tell me, Joe, were you evolved to use a keyboard and a personal computer? Were you evolved, Joe, to drive a car, ride a bike, fly in an airplane, take modern pharmaceuticals, wear glasses or use a bluetooth headset on your mobile phone? If you can tell me that we can’t or shouldn’t study the modern appliances, machines and articles of clothing that the vast majority of the population uses on a daily basis and are habituated to due to our constant use of them because they aren’t the “null” conditions, we aren’t “evolved” for using them and they aren’t “natural” enough. Honestly, Joe, I think you might have great difficulty ever getting a research paper using that unusual type of reasoning published in any respected biomechanics or scientific journal, unless, of course, someone like Dan Lieberman (funded by Vibram USA) is reviewing the paper.

      Cheers,

      Kevin A. Kirby, DPM

  3. Joe Warne November 9, 2013 at 12:44 pm #

    My point, I should clarify, is that there is no “one better than the other”. We are talking about different methods to suit different people based on individual responses. So possibly instead of constantly saying that there is “no evidence” for barefoot, a more balanced approach would be to suggest that there is no evidence either way?

    • Craig Payne November 12, 2013 at 1:40 am #

      you often talk about “cherry picking” of results to support a statement, but I have started to see a bit of a trend towards supporting conventional shoes in your posts when there is no evidence for such

      The vast majority of studies on running economy have shown that either heel striking is more economical or that there is no difference. How is that cherry picking?

      constantly saying that there is “no evidence” for barefoot, a more balanced approach would be to suggest that there is no evidence either way?

      I keep saying there is NO evidence for barefoot because the fan boys keep telling us that there is all this evidence. I do not see anyone claiming that there is “evidence” for “traditional shoes” – certainly not me. If anyone is claiming that, I will take them to task.

      Its not a mater of the “default”, its a matter of those who want to make claims, needing to back them up. To argue otherwise is the classic burden of proof logical fallacy.

      It is not my fault that almost all the research so far this year has not shown that there are any generic or global advantages to barefoot/minimalism over traditional shoes or forefoot/midfoot striking over rearfoot striking. If what I write is trending that way, then that is because that is exactly what the research is showing.

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