Take a Load Off….

A recent US study has shown the stress forces exerted on the spine by backpacks. The weight on your back can lead to cumulative injury

Article by Rupert Watkins

It’s probably no surprise to the reader that a recent US study on the effect of weighted backpacks on the spine would catch the eye of the Riddle team. With the editor and creative director ex British Army, we used to be enthusiastic participants in long debates on how to pack belt kit and bergen correctly and how to spread the load evenly across your frame.

A recently published study in Surgical Technology came across our desk. Headed up by New York based spinal specialist Dr Kenneth Hanraj, it looked at the stress forces inflicted on the spine by weighted backpacks. The study examined the effect when the spine was both in neutral and tilted forward 20 degrees – an angle many runners will go past if they lean forward when they run and certainly one cyclists will as they hunch over handlebars.

The results found for any weight in the backpack, in neutral spine the stress force acting on it was magnified over seven times whilst when the spine was flexed forward as little as 20 degrees this rose to over 11 and a half fold; as Dr Hanraj puts it one book or work file in your backpack equals seven books or files to your spine. The test methodology used both shoulder straps so those readers flinging a pack over one shoulder and compressing one side of their body might be doing themselves even less favours as making a habit of this will lead to postural changes and poor spine loading.

So what to do? Whilst the military world of 100 plus pound bergens and carrying three quarters of your bodyweight is a world away from the daily concerns of most people, ever more commuters are running and cycling into work having to carry in laptops, clothing, files and so on. Having to take work home continuously, if it involves bulky paperwork, is going to mean frequent weight carriage, either in a rucksack or overloaded attache/ brief case to hobble along with.

Firstly, and unsurprisingly the report recommends developing and maintaining a strong core. This acts as a protective jacket around the spine and enables good natural posture  – kudos for signing up to that Pilates course! Dr Hanraj’s paper also suggests strong thighs and glutes also play an important role in keeping that balanced core and acting as the body’s own shock absorbers.

Other tips:

  • Neutral spine/ good posture: if you must lug a load into work you might want to think about walking and at least keep the stress factor on your spine down to x7 rather than x11 or more. Keep the chin level, scapula retracted (that’s shoulder blades back to us non doctors) and core tight as you navigate the station concourse each day.
  • Running and cycling commuters – really try to keep any weight to an utter minimum. Leave the laptop at the office; think in terms in no more than an iPad and fresh shirt or blouse in the backpack – if that.
  • Go digital: if you have to take work home, download it and carry it on the laptop or tablet.
  • Pack carefully: think twice about what you’re taking into the office each day, do you take stuff out of habit or necessity? Can you leave items at the office? Consider walking in taking everything you need for the week on Monday morning, so you can then run and cycle freely unencumbered by any backpack for the remainder of the week.
  • Pack heavy items close to the body and (if possible) high up towards your shoulders: this keeps weight closer to the spine reducing stress forces and keeping the weight higher up on your back means your pack does not push into the small of your back pulling your spine backwards.
  • Use both straps on the backpack to spread weight equally.
  • Keep straps tight to keep backpack high on back rather than hanging down, pulling your shoulders down and pushing into the small of the back. riddle_stop 2

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