Training the brain to avoid falls
21 February 2009
Training people to avoid falls by repeatedly exposing them to
unstable situations in the laboratory helped them to later maintain
their balance on a slippery floor, according to new research from the
Journal of Neurophysiology.
The study furthered the understanding of how the brain develops fall
prevention strategies that can be generalized to a variety of
conditions. The research could eventually help people, including the
elderly, for whom falling is an important health issue.
The study, “Generalization of gait adaptation for fall prevention:
from moveable platform to slippery floor,” is published online by The
American Physiological Society. Tanvi Bhatt and Yi-Chung (Clive) Pai, of
the University of Illinois at Chicago carried out the study.
Will training transfer?
The researchers used a moveable platform which could be operated to
disrupt a person’s balance. Previous studies had shown that people could
quickly learn to maintain balance and avoid a fall with a short training
period on the platform. In this study, the researchers wanted to see
whether training on the platform could transfer to prevent a fall on a
Dr. Pai, who teaches in the department of physical therapy and whose
work has been supported by National Institutes of Health, National
Institute on Aging, said he aims to train people to maintain balance in
the face of a situation that could cause a slip-related fall.
In the study, eight participants trained on the moveable platform for
a total of 37 times. The low-friction platform was set up so that it
released unannounced, 24 of those times. This release created a
low-friction condition to cause a frontward or backward slip. The
platform does not allow the foot to slip from side to side, as would be
the case in a real-life fall.
The participants wore a harness to record the amount of assistance
needed to catch them when they fell. Motion capture instruments and
videos of the sessions also helped to document slip outcomes
(“skate-over”, “walkover” or “loss of balance”) and falls.
The participants were compared to a group of seven controls who did
not receive any training on the platform. Both groups were later asked
to walk on a vinyl surface that had one slippery spot that they could
not see. Instruments and videos were used to record the extent of their
slip. The vinyl surface represented a particular challenge following the
laboratory training, in part because it could cause the foot to slide in
Training inoculates against falls
The researchers found:
- None of the trained participants fell on the slippery
floor and seven of the eight never lost balance;
- The control group’s performance on the slippery floor
revealed their lack of training. Their performance was akin to the
trained group’s first training slip on the platform.
The trained subjects were able to transfer the skill and avoid a fall
on the slippery floor because they were better at controlling the
landing foot, that is, the foot that is on the ground during the slip.
They slowed down the movement of the foot as it began to slide forward.
The landing foot of people in the untrained group went out from under
them much faster.
“Controlling this foot, which is sliding forward, plays an important
role in maintaining stability and prevents a backward fall,” Pai said.
The researchers also found that the trained group unconsciously changed
their gait. They used a flatter landing foot and bent the landing knee
more. These changes reduced the landing force and the velocity of the
slip. Interestingly, the trained group did this while walking at their
May help elderly
The brain is able to generalize fall training from one situation to
another by modifying gait to make loss of balance less likely, the
authors concluded. These changes give the body greater stability when a
slip begins to occur. In addition, the study found that with one session
of such training, the brain pre-programs a response to slipping that can
be drawn upon quickly to stop a slip or a fall, or even to skate-over
the slippery surface without losing balance.
Fall training may be particularly helpful for active elderly persons
who put themselves in more challenging situations. Fall prevention
training may cut down on hip fractures, surgery, rehabilitation and pain
So far, the research team has used younger subjects because the
experiments carry some risk of injury. But in one study also funded by
National Institutes of Health, the researchers found that older adults
were able to learn as quickly as young adults. Further research is now
being conducted to find out if older adults can retain the training as
well as the young.
Pai and Bhatt’s research so far indicates that the effects of one
such training session, as with an inoculation, should last for at least
for four months, and perhaps much longer, to protect against one of most
dangerous falls, the backward falls.
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