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A New Study on Back Pain in the Army

New Insights On An Old Problem

A significant study on back pain in US Army soldiers was published this month. Results show that lower leg injury dramatically increases a soldiers risk for back pain. This study reinforces the idea that substantial alterations should be considered in fitness training for soldiers and treatment of injuries.

The authors investigated the relationship between past lower leg injury (LLI) and the development of back pain. They examined whether lower leg injury would increase the overall risk for back pain compared to soldiers with no injury. They also studied whether the speed of back pain development was different between previously injured soldiers and healthy ones.

Lower back pain (LBP) is one of the top 3 reasons for lost duty days in the Army, and lower leg injury one of the most prevalent injuries in the Army. That makes this study doubly important.

The Results

The authors found that sustaining an acute lower leg injury of ANY type resulted in a 70% increase in risk for back pain within 1 year. Not only that, but for LBP sufferers the problem started 10% quicker on average than in healthy soldiers. So, you’re more likely to get injured and the injury is likely to happen faster. A 1-2 punch of pain. Fantastic.

Mechanical alterations to lower limb control – overpronation of the foot, loss of ankle range of motion or stability, etc. – are clearly linked to back pain, as are neuromuscular alterations in firing sequence or intensity. In that sense the study results were unsurprising, but what IS interesting is the magnitude of the increased risk. 70% increased risk ain’t small!

Considering the overall rate of back pain in the military (especially in positions like artilleryman and infantry), these results are concerning. And they should be.

Important Details

There are 2 important things to note about the study design:

  1. The average sample size was 200,000+ so, no limitations due to small study size here.
  2. The study was designed so that each year was treated separately, looking only at NEW injuries each year. In other words, if you had either LBP or leg injury in 2008 you would be ineligible for the study in 2009 because you’d already be hurt. This is a strength of the paper – it looks at how many new injuries we are seeing year to year.

However, this means that they ignored the thousands of people who continue to suffer from pain for multiple years. Researchers were looking only for new cases. The true rate of back pain is probably higher than they report, because none of the people already injured “count” for the study. Further, a large percentage of back pain incidents in the military turn into chronic pain within a year. A 2016 study by Kardouni and colleagues reported that almost 30% of soldiers develop chronic LBP within 1 year of the initial incident. (ref 2, see study here). This obviously has huge ramifications for both healthcare costs and fighting effectiveness.

Lastly, we know that under-reporting of injuries (and other medical problems) is a problem in the military: ~50% of symptoms go unreported (see also here). I believe this is due, in part, to military culture influencing soldiers to “tough it out” rather than take care of the problem. One of the biggest reasons soldiers report for not reporting pain is the fear that it will negatively impact how they are seen by others (including career prospects).

What Does This Mean?

Because of these factors, true rates of back pain are likely much higher than reported in this study or others.

We know military personnel with a history of low back pain are more likely to have recurring pain even after leaving the armed forces than people who remained civilians. We also know that the general fitness training soldiers undergo is not sufficient to build resilience to lower back pain. In some ways, it is likely that training actually contributes to the occurrence of back pain (running is a well documented factor). Soldiers are pushed hard to be fit – it’s essential to fighting effectiveness – but they are not taught how to move!  Training to be “fit” without coaching proper movement is a very good way to get injured, and here’s the study that shows it.

Athleticism is a skill, not simply a test result.

There are obviously times when toughness is a major goal of training (SF selection, advanced schools, etc.). Given the mission of the military to kill people and break things as efficiently as possible, that’s completely appropriate. However, I don’t believe general physical training at duty stations should be one of these times. The less effective general fitness training at duty stations is for warding off injury, the less resilient a soldier is when they head to the field, a school, or deployment.

 

References:

  1. Seay JF, Shing T, Wilburn K, Westrick R, Kardouni JR. Lower-Extremity Injury Increases Risk of First-Time Low Back Pain in the US Army. Med Sci Sports Exerc. 2018 May;50(5):987-994.
  2. Kardouni JR, Shing TL, Rhon DI. Risk factors for low back pain and spine surgery: a retrospective cohort study in soldiers. Am J Prev Med. 2016;51(5):E129–38.

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