To the Editor : The Journal of Strength & Conditioning Research

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Manuscript Clarification

To the Editor

Berger, Russell

Journal of Strength and Conditioning Research 28(11):p 3312, November 2014. | DOI: 10.1519/JSC.0000000000000721
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This Manuscript Clarification is on the ahead of print manuscript and is not the final soon to be published manuscript. Ahead of press papers are not in their final form as Authors and Editorial corrections have not yet been made. This is noted on such papers that are on-line before final publication in the journal.

To the Editor:

I am writing you with a request for clarification regarding the study titled “The nature and prevalence of injury during CrossFit training.” I found a copy of the study published online and conducted an interview with the study's author, Dr. Paul Hak.

Here are my questions:

  1. Hak's study cites another article titled “Consortium for Health and Military Performance and American College of Sports Medicine Consensus Paper on Extreme Conditioning Programs in Military Personnel.” Hak writes that this article “Highlighted significant risk of injury in those involved in extreme conditioning programs such as crossfit.” I have read the CHAMP paper, and it contains no data regarding risk of injury, and therefore does not seem to support this statement.
  2. Hak's article attempts to explain the prevalence of shoulder and lower back injuries reported. At first, he states the following:

“During CrossFit workouts, Olympic style overhead movements are performed at high repetition range and at high intensity often with heavy weights. This may lead to poor form and placing the shoulder at extremes of motion in the at-risk position and predispose to injury.”

Next, he says this:

“Again the use of high intensity, high repetition, and heavy weight in exercises requiring strict form may explain the high number of low back injuries in our sample.”

Finally, he concludes that:

“The high prevalence of shoulder and low back injuries, however, due to the high intensity, high repetition, and heavy weight movements, needs to be considered…”

This conclusion is unwarranted and seems to be a nonsequitur. The article moves from two “may” statements that speculate about the effects of high-intensity exercises to a “due to” statement that affirmatively concludes that there is a causal relationship between one aspect of CrossFit training and what he calls a “high prevalence” of shoulder and low back injuries. No evidence, argument, or citations are provided to bridge the logical gap between the previous statements and the conclusion.

I interviewed Paul Hak shortly after making this observation, and he informed me that this unsupported conclusion must be the result of a typo in the editing process. I would hope that given the serious nature of such a typo, which falsely implies that CrossFit causes a high prevalence of shoulder and low back injury, this will be corrected.

In Response:

With regard to point 1 and the CHAMP study, this quote taken directly from the conclusions of the study: “However, a measurable and costly increase in injury risk could arise when ECPs are performed inappropriately, with an anticipated consequent reduction in individual and unit operational and combat readiness when one or more injuries are sustained.” This reference was used as a lead into the potential benefits and risks of extreme conditioning programs and also that there was a paucity of actual evidence in the data. I therefore think its inclusion as a reference is justified.

With regard to point 2, I accept the change through the article and that as an over sight a “may be” has been omitted. Therefore, I would accept the changing of the point highlighted by Mr Berger to include this and therefore should read: “The high prevalence of shoulder and low back injuries, however [which may be] due to the high intensity, high repetition, and heavy weight movements, needs to be considered and taken into account when programming WODs to reduce these injuries and change the perception of injury in CrossFit.”

Paul Hak

Copyright © 2014 by the National Strength & Conditioning Association.