Effect of fatigue on running kinematics

It was only a month ago that I wrote about the effect of fatigue on foot function and now there is another publication to add to the mix.  The reason that the issue is important is that most biomechanical studies and clinical assessments are done when runners are fresh and not fatigued. When they are fresh, they may not display what are assumed to be risk factors for an injury that they may display when they are fatigued. Obviously, the later part of every run and race is done in a fatigued state! The previous article looked more at the affect on foot function, whereas this new study looked more at running kinematics and the effects of core endurance:

Kinematic changes during running-induced fatigue and relations with core endurance in novice runners
Ian F. Koblbauer, Kimberley S. van Schooten, Evert A. Verhagen, Jaap H. van Dieën
Journal of Science and Medicine in Sport; Article in Press
Objectives
This study aimed to investigate kinematic changes experienced during running-induced fatigue. Further, the study examined relations between kinematic changes and core endurance.

Design
Repeated measures and correlation.

Methods
Seventeen novice runners participated in a running-induced fatigue protocol and underwent core endurance assessment. Participants ran at a steady state corresponding to an intensity of 13 on the Borg scale and continued until 2min after a Borg score of 17 or 90% of maximum heart rate was reached. Kinematic data were analyzed for the lower extremities and trunk throughout a running protocol and, on separate days, core endurance measures were recorded. Changes in pre- and post-fatigue running kinematics and their relations with core endurance measures were analyzed.

Results
Analysis of peak joint angles revealed significant increases in trunk flexion (4°), decreases in trunk extension (3°), and increases in non-dominant ankle eversion (1.6°) as a result of running-induced fatigue. Post-fatigue increased trunk flexion changes displayed a strong to moderate positive relation with trunk extensor core endurance measures, in contrast to expected negative relations.

Conclusions
Novice runners displayed an overall increase in trunk inclination and increased ankle eversion peak angles when fatigued utilizing a running-induced fatigue protocol. As most pronounced changes were found for the trunk, trunk kinematics appear to be significantly affected during fatigued running and should not be overlooked. Core endurance measures displayed unexpected relations with running kinematics and require further investigation to determine the significance of these relations.

The results show changes in kinematics after the fatigue protocol that are assumed to be associated with an increase in injury risk (ie ‘overpronation) and poor running form (the increased forward lean of the trunk).

The surprise finding of this study was the relationship between the changes in kinematics and core endurance. They found that “participants who displayed better core endurance exhibited larger trunk kinematic changes when fatigued“. This does raise some questions about the widely assumed importance of the core in running and also questions about the mechanism of the relationship between ‘core stability’ and running kinematics.

I not sure how to interpret this result as they are counterintuitive. I have no doubt about the importance of the core, but the results of the study above are the results of the study and we can’t just wish away studies that we don’t like the results of if they have no fundamental flaws in them (I can’t see any in this one). Somehow the authors did manage to conclude from this: “This may support core endurance training in runners“. I am not sure how the data in this study shows that, even though they are probably right about the importance of core endurance training!

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

Koblbauer, I., van Schooten, K., Verhagen, E., & van Dieën, J. (2013). Kinematic changes during running-induced fatigue and relations with core endurance in novice runners Journal of Science and Medicine in Sport DOI: 10.1016/j.jsams.2013.05.013

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8 Responses to Effect of fatigue on running kinematics

  1. Brian Martin June 25, 2013 at 2:14 am #

    Hi Craig,

    Nice post on this study. It does seem counter intuitive I agree. Personally I don’t necessarily see how being able to plank all day long translates into better ability to maintain good movement patterns and postures during running.

    Planking is very static versus the dynamic nature of running. I like the idea of planking as developing awareness of core but building up running strength with use of light barbells as soon as safe and possible. Holding your trunk extended under load while moving through squats, lunges, dead lifts or even running drills seems to me more specific.

    • Mark Richard June 30, 2013 at 8:25 pm #

      Lydiard used hill drills for this reason

      • Craig Payne July 4, 2013 at 1:51 am #

        Care to provide a reference for that? I recall Arthur Lydiard saying lots of things about hill drills, but not for this reason. Did I miss it?

  2. Craig Payne June 25, 2013 at 8:12 am #

    Thanks Brian; yes “counterintutitive” is the word. There have been a couple of comments in twitter that the 140 word limit does not do justice to.

    Here is exactly what the authors reported:
    a significant positive relation was found between increased peak trunk flexion angle and extensor endurance (r = 0.735, p = 0.001), displaying a relation between larger kinematic changes and better core endurance.”

    That is what the data showed.

  3. Kevin Maggs June 25, 2013 at 10:38 am #

    This was not the first study to show the trunk being carried further forward during running in a fatigued state. Elliot et al. [1], had similar findings “way back” in 1980. There are two things I find interesting about this latest study.
    The “one size fits all” approaches such as Chi, Pose and Evolution all promote a “forward lean”. In my experience, runners tend to implement this as a forward lean from the waist. Proponents will argue that runners are instructed to lean from the ankles, but my experience tells me it doesn’t usually work that way (and yes, I’ve taken both Chi and Pose clinics out of curiosity). Even if it did, a forward shift of the center of gravity would place even greater strain on the muscles in the posterior chain – particularly the low back extensors if the runner is leaning from the waist. As we see in this latest study, fatigue increased trunk inclination during running. If runners are already arbitrarily told to lean forward in a “one size fits all approach”, they are essentially being told to exaggerate the way they will get when they are fatigued.
    In a slightly different study, Helbostad et al. [2], found that following a sit-to-stand fatigue protocol, both the step width and the medial/lateral trunk acceleration increased during walking following the fatiguing protocol. This is interesting since the sit to stand action is in the sagittal plane, yet gait changes were found in the frontal plane. This study unfortunately did not measure trunk inclination in the sagittal plane.

    1. http://www.ncbi.nlm.nih.gov/pubmed/7449034
    2. http://bit.ly/11Kccnd (opens the full PDF article)

    • Craig Payne June 25, 2013 at 9:32 pm #

      Thanks Kevin! I have a Chi Running course that I am doing coming up soon!

      The twist with this study was the forward lean was higher in those with more core endurance!

  4. Mark Richard June 30, 2013 at 8:34 pm #

    Coaching cues such as the “lean” are not scientific fact and demonstrate a poor understanding of gravity.

  5. Marc Doré July 3, 2013 at 3:47 am #

    Very interesting!

    I see this conclusion from two different ways: First we have to remember the development of the human body. The primary curve of the spine is a kyphosis. When we were babies we were all in that position until we started crawling and rolling and sitting…As we grow we tend to come back to this position; the way we sit, we get older we lean over things to walk and finally we pass away in a fetal position. So naturally our body wants to go in that position. So no big surprise to see that untrained runners when pushed to the “limit” will move in that position.

    Secundo what was their measure for core stability? There’s still a lot of confusion with that term. We have to be careful. Planking is not the perfect core exercise. My definition (which I think is the correct one) is controlling movement at the trunk in ALL directions while performing movement with 1 or many extremity(ies). So if they used the plank for example, it doesn’t give us a real measure of core stability because all the extremities are immobile unlike running. Then when they compared with the data from the running part it means nothing (other than good plankers are weaker when they run!).

    Anyway that’s my thought on that research. Still very interesting to read about it and from you guys!

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