Calcaneal stress fracture – forefoot or rearfoot strikers?

Is a stress fracture of the calcaneus or heel bone due to the impact loads from heel striking or from the shear stress through the bone from the pull of the Achilles tendon? If I was to ask this question on a barefoot or minimalist forum, what answer do you think I would get? Of course, it will be a resounding ‘heel striking’! How do they know that? Is it because it is true or is it because they want to believe it is true? Wishful thinking does not  make something true!

Calcaneal stress fractures are not very common, so no one can claim to have any great clinical experience in dealing with them (I have probably only seen a dozen or so in the last 30 or so years¹). The comments in a few of the standard textbooks that I checked is that they are due to heel striking, as it does make intuitive sense that the repeated impacts can overload the bone and cause a stress fracture if the bone is not given time to adapt to the loads. However, despite these comments, there has been a number of recent published reports of a stress fracture of the calcaneus in forefoot strikers and minimalist runners. For example, Salzer et al reported one in a minimalist runner and Reuteman et al reported another at the APTA conference. If you check around social media, blogs and forums for barefoot and minimalist runners, you do see an increasing number of reports of calcaneal stress fractures (see this for comments). Some comments I have seen are from very perplexed minimalist runners confused as to how can they get a calcaneal stress fracture if they were forefoot striking.

What now appears to be obvious is that if heel striking is “the cause“, then why are there an increasing number of these reports of calcaneal stress fractures in forefoot strikers and minimalist runners? Maybe the impact of heel striking is not the cause, but the cause is a shear stress going through the calcaneus from the pull of the achilles tendon. Maybe the foot strike pattern has nothing to do with it.

I go where the evidence takes me until convinced otherwise.

¹If my memory serves me correctly, all of those were probably in heel strikers. This was probably deceptive as most runners are heel strikers, so the assumption was that they were due to the impact loads of heel striking.

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4 Responses to Calcaneal stress fracture – forefoot or rearfoot strikers?

  1. Thomas Twomey March 20, 2013 at 1:39 am #

    I was lucky enough to hear Dr Joe Hamill speak on this topic at the ISBS conference at ACU this year and it certainly enlightened me on the topic. As you mentioned in some of your other blogs when you forefoot strike the positive of a reduced impact peak will cause an increase in strain on other mechanisms. I am a rookie biomechanist and discussions such as this are as ever educational.

  2. Craig March 20, 2013 at 4:32 am #

    Thanks Thomas; I have talked to Joe many times about these issues. You can’t take the load off one structure without increasing it on another! It is 6 of one and half a dozen of the other. Unfortunately so many miss that when discussing these topics.

  3. Thor Vandehei June 30, 2013 at 8:43 pm #

    Craig,

    A few comments on the paper you cited – Salzler (2012):

    1) No where in the paper do the authors actually measure the footstrike
    pattern of their 9 patients. There seems to be an assumption that because
    they switched to “minimalist” shoes they are now no-longer heel-strikers.
    I my opinion a very bad assumption, and major weakness of the paper.

    2) All 9 of the patients, apparently, switched to “minimalist” shoes with
    little or no transition period (5 out of 9 with no transition, and of
    the remaining 4 the longest transition period was a paultry 2 months!).
    NB, nearly all their injuries occured soon after the switch, except
    one odd ball, who was injured after 10 months from switching.

    An alternative hypothesis to yours concerning calcaneal stress fractures
    occuring in “minimalist” runners is that they continue to heel-strike after
    the transition, and in shoes with little or no padding. If one reads the
    paper you can see that the authors cite this hypothesis as well:

    “The presence of a calcaneal stress fracture raises
    the question of whether the patient was utilizing minimalist
    running footwear with a heel strike gait pattern. Our patient
    with the calcaneal stress fracture either represents an atypical
    mechanism for generation of such an injury or, more likely,
    was running in minimalist running shoes with a heel strike
    gait pattern.”

    Sorry for the very late reply, I’m still catching up on my reading of this very
    interesting blog.

    Cheers,

    Thor

  4. Craig Payne June 30, 2013 at 9:35 pm #

    Thanks. Point taken re Salzar paper and that they could be heel striking still.

    However, since writing the above I keep hearing about more and more “non-heel” strikers developing calc stress fractures (and I know that anecdotes are not data).

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