A primer on why we fall – and why everybody is at risk
Editor’s note: Last week, we covered the importance of fully understanding the mechanism of injury and the resulting bodily injury that happens during a fall. Today, we cover why people fall and how it’s not just because of missteps or slippery surfaces. This is the second installment of three installments.
It’s easy to understand why construction workers or retail workers, who are working in unsafe environments or are constantly on their feet, are more likely to fall than other workers. Seniors also are at risk because they may have lower body weakness; vision problems; foot pain; or use medicines that could make them less sure-footed.
But science – and experience – shows us that just about anybody can be prone to a fall for all kinds of reasons – wet flooring, uneven sidewalks or improper footwear.
For most of us, walking is something we do without much thought. In reality, the simple step of putting one foot in front of the other requires a complex partnership between our muscles and our central nervous system.
Regarding slips and falls, a 2013 report in the Encyclopedia of Forensic Sciences shows that there are two important phases to consider: Soon after the heel meets the ground and when the front part of the shoe or foot is touching the ground.
And there are plenty of factors that impact our stability. The farther apart our feet are as we stand, for instance, the more stability we have. And our center of gravity as compared to that base of support or, foot spread, also is critical.
An article on HumanKinetics.com summed it up this way: “High stability (low mobility) is characterized by a large base of support, a low center of gravity, a centralized center of gravity projection within the base of support, a large body mass, and high friction at the ground interface. Low stability (high mobility), in contrast, occurs with a small base of support, a high center of gravity, a center of gravity projection near the edge of the base of support, a small body mass, and low friction.”
How our brains are involved
Our brains, of course, also play a role in the way we walk and assess slippery or tricky walking surfaces.
When we’re walking, we’ll look to see if the path ahead of us is safe. If it is, we’ll continue that evaluation as we walk forward – shifting our weight or changing our gait if the path turns out to be slippery or uneven.
“It is clear that ‘expectancy’ is required to walk – that is, during walking, we expect the ground to be stable and, as such, we modify our gait to traverse the terrain with appropriate force and speed …” says the forensics sciences report. “… If the ground is not stable, there will be a motion perturbation [where expectancy didn’t match reality]. This perturbation, if not controlled, could lead to slips and falls.”
We’ve all been there. We’re walking forward and get to a slippery spot. We change our gait, but not quickly enough. As we stagger, our muscles don’t come to the rescue and we fall.
Age can slow down our perceptions of potential dangers. One study found that “sensory changes,” including not understanding how slippery a floor is, in the elderly increased the chance of slips and falls.
The elderly also take longer to change their gait to avoid slipping, according to the forensic sciences report. Younger people take one step to keep from falling. Older people need at least two.
And, of course, our brains do more than just help us assess the potential danger. They also signal our body on how to react as soon as we start to fall.
There is a reflexive response from our brain that occurs when we get off balance. We extend our arms or hands in an effort to break the fall. In fact, the primary injury to arms and hands is important to any analysis of what happened during a fall.
It’s a fall. But what kind?
Indeed, not all falls are created equal. The injury from a slip, for instance, could be completely different from a stumble or a trip. Knowing how the fall initially occurred will give you a foundation for what body part struck the ground or another object first.
According to literature, there are multiple kinds of falls. Rotational, same level, elevated level, tumble, free fall, trip, stumble and slip are among them. Many overlap in dynamics and biomechanic identifiers.
Coming next week: We’ll cover the more common types of falls that we have seen over the past 20 years in our practice and their associated hallmarks.