What are you (back) packing?

Backpacks are something that most children in developed countries use and wear — it’s essentially a requirement for modern schooling systems. How to properly wear these backpacks has been a topic of discussion for many years, but I still find people are generally confused about what solid principles to use that help improve personal safety when wearing a backpack — especially for children. I’ll give you a list of suggestions for improving safety — but first let’s deepen our understanding of the topic.

What Happens with Heavier Backpacks?

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In general, a few things happen when using heavier backpacks. Past studies have assessed backpack loads at greater than 20% of the child’s body weight, finding that blood pressure increases significantly, likely due to compressing our lung’s ability to work as we lean forward to compensate for the load on our back. And we can’t avoid leaning forward while carrying a backpack because this leaning action maintains our balance — a bit like carrying all your groceries in one hand requires you to lean in the opposite direction. Unfortunately, it’s not even as simple as a 20 lbs backpack is twice as bad as a 10 lbs one — it actually appears the load placed on our body increases at a more significant rate. For example, investigation shows that the difference between a backpack at 15% of body weight and a backpack at 30% of body weight (a 200% increase) creates a 239% increase in load on the low back! Other outcomes with heavier backpacks include more forward head carriage (placing demands on the upper back and neck), and some rarer outcomes like pinched nerves at the shoulders (called Rucksack Palsy). 

So should I use my body weight as a guide to limiting my backpack weight? 

No, and yes. The feeling of fatigue (or being tired) due to carrying a backpack appears to be a better predictor of low back pain in children than the actual relative weight of the backpack. For example, of students who reported feeling fatigued while wearing backpacks, 15% complained of back pain at that moment in time (point prevalence). More striking however, is that of those complaining of feeling fatigued due to their backpacks (like above), 40% had experienced back pain at some time during their childhood (lifetime prevalence). This is in stark contrast to those who did not complain of feeling fatigued by their backpacks, where none of them (0%) had current back pain, and only 7% reported ever having back pain. To take this a step further, the time spent wearing a backpack was found to be correlated with an increased likelihood of a child having back pain at some time during their childhood. So perhaps it is in our better interest to monitor how children feel their backpack is impacting them — do they feel physically tired as a result of the weight? — and limit their overall time spent wearing backpacks. 

Interestingly, the backpack weight, relative to individual body weight, was not directly related to back pain in children. However, I did say no, and yes, because intuitively we can suggest that a greater load and/or time spent wearing a backpack may lead to an increased chance of feeling fatigued by the backpack. And fatigue, as pointed out, could be our best indicator when things might start causing problems. 

Still with me? Research is rarely described in absolutes, unfortunately. But with these concepts in mind, here are some general recommendations to apply for safe backpack use. 

1. Pack it Light! Although I just talked extensively about how this is not the be-all and end-all of backpack use, it remains an important consideration. Go one step further and use multiple compartments to distribute the weight of the pack, positioning the heaviest items closest to your back. 
2. Limit wearing time! If you can put the pack down safely from time to time, do so!
3. Use fatigue as your guide! Total pack weight doesn’t relate to future or current problems, but feeling fatigued does.
4. Wear two straps where possible! Also use chest straps and waist straps to distribute the pack weight to your torso and hips.

For more information, to see if your child is wearing their backpack right, or if you have any questions, contact me or make an appointment at the clinic (905-634-6000, drjimgilliard@gmail.com), leave a comment below, or visit the Ontario Chiropractic Association website. 

Reference information:

1. Goh J-H, Thambyah A, Bose K. Effects of varying backpack loads on peak forces in the lumbosacral spine during walking. Clin Biomech. 1998;13(S1):S26–31.
2. Goodgold SA, Nielsen D. Effectiveness of a school-based backpack health promotion program: Backpack Intelligence. Work. 2003;21(2):113–23.
3. Hong Y, Li JX, Wong AS, Robinson PD. Effects of load carriage on heart rate, blood pressure and energy expenditure in children. Ergonomics. 2000;43(6):717–27.