Impact Reduction with Chi Running

When new research is published, its always intriguing to watch how different communities respond to it and the interpretation or spin that gets put on it¹. I already discussed the The ‘Running Shoes Causing Knee Osteoarthritis’ Debacle in a previous article and how the spinning and re spinning of false headlines lead to a myth. This paper was recently published:

Impact reduction during running: efficiency of simple acute interventions in recreational runners.
Giandolini M, Arnal PJ, Millet GY, Peyrot N, Samozino P, Dubois B, Morin JB.
Eur J Appl Physiol. 2013 Mar;113(3):599-609.
Running-related stress fractures have been associated with the overall impact intensity, which has recently been described through the loading rate (LR). Our purpose was to evaluate the effects of four acute interventions with specific focus on LR: wearing racing shoes (RACE), increasing step frequency by 10 % (FREQ), adopting a midfoot strike pattern (MIDFOOT) and combining these three interventions (COMBI). Nine rearfoot-strike subjects performed five 5-min trials during which running kinetics, kinematics and spring-mass behavior were measured for ten consecutive steps on an instrumented treadmill. Electromyographic activity of gastrocnemius lateralis, tibialis anterior, biceps femoris and vastus lateralis muscles was quantified over different phases of the stride cycle. LR was significantly and similarly reduced in MIDFOOT (37.4 ± 7.20 BW s(-1), -56.9 ± 50.0 %) and COMBI (36.8 ± 7.15 BW s(-1), -55.6 ± 29.2 %) conditions compared to NORM (56.3 ± 11.5 BW s(-1), both P < 0.001). RACE (51.1 ± 9.81 BW s(-1)) and FREQ (52.7 ± 11.0 BW s(-1)) conditions had no significant effects on LR. Running with a midfoot strike pattern resulted in a significant increase in gastrocnemius lateralis pre-activation (208 ± 97.4 %, P < 0.05) and in a significant decrease in tibialis anterior EMG activity (56.2 ± 15.5 %, P < 0.05) averaged over the entire stride cycle. The acute attenuation of foot-ground impact seems to be mostly related to the use of a midfoot strike pattern and to a higher pre-activation of the gastrocnemius lateralis. Further studies are needed to test these results in prolonged running exercises and in the long term.

It certainly got those in the Chi Running community excited as the midfoot strike pattern that was used was the same as used by Chi runners. There were are number of blog posts (eg) applauding the study, but as usual, it exposed a common problem with the reading, appraisal and interpretation of research by those who are not familiar with the reading, appraisal and interpretation of research. All the usual trope of fallacies such as confirmation bias were on display.

It  was good study, but I will make these comments.

  1. There were only 9 subjects (which I do not necessarily have a problem with as I understand the concepts of sample size calculation, power analysis and effect sizes; and with a ‘within subjects’ comparison you can get away with smaller sample sizes). Interestingly no one on any the Chi running websites I checked even raised this 9 as an issue; yet if you check back to some older posts on those sites they were certainly very critical of the sample size if they do not like the results of a study! Why not also criticize a study that they like because it also had a small sample size? (Ironically, those who do not like the results of the study I wrote about here, are criticizing its sample size of 36 as being too small…don’t figure!)
  2. It was an acute intervention. The same results may or may not be applicable to those who are habitual midfoot strikers (see postscript added below for more).
  3. Tibial stress fractures, that only make up around 4% of running injuries, is the only injury linked to impact forces, so going to midfoot striking is not going to be a panacea to reduce injuries! Yet, that is exactly how many on Chi running websites interpreted this study as evidence that you get less injuries with Chi running, when it was not even a study on injuries! (for more on impact forces and injury, see this post).
  4. It is also what I like to call a ‘zero sum game’ or “Law of Conservation of energy”, which means that the total “energy” in the system remains the same. This implies that you can not change the load in one part of the gait without increasing it somewhere else. In order to run with the midfoot stike to lower the impact forces you have to have certain muscles working harder (which the study sort of showed: “higher pre-activation of the gastrocnemius lateralis“). This has the theoretical effect of exposing those muscles, tendons to a higher risk for injury, so you just trade one risk for another.

I have already discussed Chi running here and have a previous rant about it….and I actually have nothing against Chi running! Its just the claims that are made for it (eg the second coming of the messiah) and the misuse, misrepresentation, misquoting and misinterpretation of the science and the reaction to this research on the Chi Running websites that I checked just reaffirms those views.

As always, I go where the evidence takes me until convinced otherwise.

POSTSCRIPT: I just reported on a similar study that did a 3 month intervention to midfoot striking rather than the acute intervention of the above study. In that study, they reported a significant difference in a number of the impact parameters at 1 month, but most had returned to baseline by 3 months. This suggests that the results of the above study are not valid.

¹Nothing to do with running, but I just read these two posts on Left Brain/Right Brain about how the anti-vaccine cranks spun research to show what it didn’t show! (No, the autism prevalence did not go down in Denmark after the removal of thimerosal and No, the autism “rate” in California did not go down after removing thimerosal from vaccines) and this one on Quackometer: How media reports of electrosensitivity may be responsible for electrosensitivity. They do show how the gullible get taken in.

Giandolini, M., Arnal, P., Millet, G., Peyrot, N., Samozino, P., Dubois, B., & Morin, J. (2012). Impact reduction during running: efficiency of simple acute interventions in recreational runners European Journal of Applied Physiology, 113 (3), 599-609 DOI: 10.1007/s00421-012-2465-y

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7 Responses to Impact Reduction with Chi Running

  1. Jonathan Birthmore April 7, 2013 at 1:50 pm #

    Hey Craig, really enjoy your research appraisal. Out of interest are you aware of any concrete evidence that suggests that a certain running posture is most biomechanically efficient/effective.
    In a lot of the physical therapy literature there is a reccomended “ideal” static posture and categorised deviations from this (I.e. sway back, hyperlordotic/kyphotic) however dynamically I can’t seem to identify anything beyond anecdotal evidence illustrated in pose technique, chi running and the like.
    Gait retraining is quite an interesting area but again literature is limited.

    Considering there is limited quality research in sports podiatry how do you suggest a soon to graduate student should approach practice? If a certain subject has a body of evidence to guide practice but that evidence is of a poor quality from a research standard what do you go by?

    Sincerely yours,


  2. Craig April 7, 2013 at 6:47 pm #

    There is no evidence; that is the point I keep making. They all claim that there is, but it is the misuse, misrepresentation, misquoting and misinterpretation of the science. You will find numerous statements on blogs and in social media that the above research proves that Chi running can lead to less injuries based on the above research!

    Do you see any elite runners Pose or Chi running?

    The best advice I have for clinicians is: what is the load in the tissue that is damaged –> how can you reduce that load and increase the ability of the tissues to take that load. It not about minimalism, Pose, Chi, barefoot, whatever, its about the load in the tissues. If Chi running is the way to reduce the load in the problematic tissue, then I have no problem with it. Its just the ,marketing of any one of the them as a panacea that I have a problem with.

    • Jonathan Birthmore April 7, 2013 at 10:26 pm #

      I have heard that approach before and certainly agree with it in accordance with the tissue stress theory. However in saying that I have also witnessed many podiatrists who use this approach without considering the effect on other tissues. Ultimately one issue is exchanged for another.As you have mentioned in other posts, energy is continuous and not something that can be simply eradicated. Other tissues must take on the load .
      Perhaps though certain parts of the body are more capable of tolerating these forces and that’s what is trying to be achieved with these “posture” theories.
      Again it sounds great in theory but there is little to no evidence for what this ideal posture is but I can at times understand the claim that heel raises, orthotics etc are simply a treatment of the symptoms and not the cause.
      Then again it may simply involve conditioning the injured tissue once stress is reduces to improve their tolerance to load. Eventually removing or reducing the dependance on orthotics etc as the tissue strengthens

  3. Craig April 8, 2013 at 1:44 am #

    …assuming the tissue can be adapted … all depends on the magnutde of the load, the tissue health and the compliance…

    Of course you take into account which tissues are loaded more to offload others.

    eg Chi Running:
    Reducton –> heel impacts
    Increase –> loads in achilles & post tib tendons; greater dorsiflexion moments of forefoot on rearfoot, etc

    …the above paper did not report where the increases were to allow the heel impact to be reduced (except the comment re greater preactivation of the gastroc).

  4. Jonathan Birthmore April 8, 2013 at 8:29 am #

    I agree with you. I think you’ll agree that many of these philosophies and theories evolve from everyone wanting a quick fix, suit all blueprint approach. Unfortunately the body is far too conplex for that, or we just haven’t found the answers we need at this stage. It’s dissapointing as it limits progression, as you’ve outlined with the authors of the above study failing to monitor the consequential translation of load elsewhere in the body.
    What about the physiological function of tissue in relation to different foot strike patterns. On one hand mid/forefoot increase post leg loads but it also alters the manner in which these muscles contract(eccentric as opposed to concentric).
    Research indicates eccentric loading results in a noticeably greater levels of DOMS and hence many training programs that are well programed account for this. On the other hands your collegies have identified eccentric strengthening as the gold standard of chronic achilees tendinopathy treatment. Are we inheritantly altering the way in which the post leg is designed to function during running by heel striking?

    • Craig April 8, 2013 at 8:38 am #

      Not sure how to answer that! Its a good point, but I don’t think anyone has given the issue much consideration. I will be seeing someone (JC) in a few days who will probably know. I will ask her.

  5. Craig April 23, 2013 at 11:11 am #

    I have added what is probably an important postscript to the article above:

    POSTSCRIPT: I just reported on a similar study that did a 3 month intervention to midfoot striking rather than the acute intervention of the above study. In that study, they reported a significant different in a number of the impact parameters at 1 month, but most had returned to baseline by 3 months. This suggests that the results of the above study are not valid.

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