Carrying an object while walking, whether a child or a cell phone, can greatly alter the outcome if we lose our balance.  How many times have you attempted to carry all the groceries from the car in one trip, decided you can carry those extra bags for your vacation, or loaded yourself up with that one extra item in the house before you walked down some stairs?  It’s these actions that we all do on a regular basis that put us at an increased risk from effectively responding to a moment of imbalance by being able to brace for a fall.

A moment of imbalance can encompass several scenarios, often grouped into one of three categories: slips, trips, and missteps; all of which we have faced multiple times throughout our lives.  Slips most often occur when we place our foot on the ground with insufficient friction while walking.  Our foot slides forward and/or to the side, causing us to lose our balance and fall backwards or to the side.  Trips most often occur when our leg swing is interrupted, preventing our foot from arriving where we need it.  Trips occur under a variety of situations, from undetected elevation changes in the sidewalk on your evening walk or tripping over the family pet that just walked between your legs.  Last, missteps are simply any step that is insufficiently placed to accept the weight transfer of your body, which can be especially important when that weight transfer also includes the things you are carrying.

With our hands full carrying loads like groceries, our injury risk may increase due to an increased inability to brace for a fall during moments of imbalance.  By bracing for a fall, an individual has successfully moved their arm to grab onto a railing or contact the ground before the head or pelvis does, thus decreasing the impact force of that fall.  Not bracing for a fall can lead to an increased risk of severe injury consequences.  Research has shown that unbraced falls from standing height can lead to upwards of 300 g of acceleration impacting the head.  As a comparison, a study looking at braced falls with the hands used at the last moment before impacting the ground found peak accelerations to the head of only 15.2 g.  That’s a 20x decrease in head impact by simply bracing at the last moment before contacting the ground!  To give an idea on what that means for injuries (e.g., concussion), the average acceleration associated with concussion in professional football players was found to be only 98 g.  This highlights just how important bracing becomes in reducing the forces the body experiences when falling.

For older adults, the risk of falling is an ever-present danger faced when going about the activities associated with daily living.  The Canadian Institute of Health Information (CIHI) reported seniors (individuals 65 and older) make up 71% of hospital stays due to unintentional falls, with hip fractures the most likely cause of hospitalization.  While it is currently not known how much carrying loads played a role in these studied injuries and hospitalizations, research evidence suggests carrying loads or holding objects certainly plays a role. One study found that individuals exposed to a loss of balance while holding objects preferentially hang onto the object instead of protecting themselves, even when the object they are holding is not helpful in regaining their balance! Simply put, if you start to fall while texting and walking, you are more likely to protect your phone than your own body. It is scientific findings like these that should give us pause when we decide to routinely carry that extra item instead of keeping our hands free.

 It should be noted that the potential risk posed by carrying loads when responding to moments of imbalance is not unique to seniors.  That same CIHI report also stated that while most hospital stays due to unintentional falls may be seniors, individuals younger than 65 years of age make up 72% of emergency department visits due to unintentional falls.  The difference in injury rates has to do with response-ability, as falls from standing height have enough impact energy to cause hip fractures in young adults, but young adults have an increased ability to rapidly place their hands in a position to brace for impact that results in staving off any major hip injuries.

Whether it be attempting to make just one trip from the car with your groceries, or carrying that extra item down the stairs so you don’t have to make another trip, we should be thinking about what we are trying to accomplish – delivering of an item, posting on Instagram, or arriving safely. While we may often think about falls in terms of overall ability, age, or strength, we often don’t consider the potential negative influence that carrying an object may have on our ability to brace for falls.  At the end of the day, take that extra trip to the car, the extra trip up and down the stairs, or post your selfie while seated, because it may just be what helps prevent serious injury.

References

[1] Doorly, M. C., & Gilchrist, M. D. (2006). The use of accident reconstruction for the analysis of traumatic brain injury due to head impacts arising from falls. Computer methods in biomechanics and biomedical engineering, 9(6), 371-377. https://www.tandfonline.com/doi/full/10.1080/10255840601003551

[2] Investigation of Amusement Park and Roller Coaster Injury Likelihood and Severity, Exponent Failure Analysis Associates Report, prepared for Six Flags, New York, August 2002.

[3] Pellman, E. J., Viano, D. C., Tucker, A. M., & Casson, I. R. (2003). Concussion in professional football: Location and direction of helmet impacts—Part 2. Neurosurgery, 53(6), 1328-1341. https://academic.oup.com/neurosurgery/article-abstract/53/6/1328/2887895

[4] https://www.cihi.ca/en/exercise-caution-canadians-frequently-injured-in-falls

[5] Bateni, H., Zecevic, A., McIlroy, W. E., & Maki, B. E. (2004). Resolving conflicts in task demands during balance recovery: does holding an object inhibit compensatory grasping?. Experimental brain research, 157(1), 49-58. https://link.springer.com/article/10.1007/s00221-003-1815-8

[6] Hsiao, E. T., & Robinovitch, S. N. (1997). Common protective movements govern unexpected falls from standing height. Journal of biomechanics, 31(1), 1-9. https://www.sciencedirect.com/science/article/abs/pii/S0021929097001140