There is a good chance you are sitting
down right now. It’s possible you’ve
been sitting all day, or maybe you’ve
even been sitting every day for the last
few decades.
“There is a trend in the 21st century
that 80 percent of our jobs require
sitting, and it’s even more so when
you include leisure time,” says Marit
Johnson (CE 96), a PhD candidate in
biomedical engineering at SD Mines.
You may guess that spending all this
time in a chair is not so good for your
health. In fact, research is now showing
prolonged sitting may contribute to
lower back pain. “Eighty percent of
us will experience back pain in our
lifetime,” says Johnson. "If your job
requires long hours in a chair, back pain
can be a real issue."
Johnson’s research is focused on the
intervertebral discs of the lower back.
These discs are in between the vertebrae,
or bones, of the spine, and their softer
tissue provides cushion and flexibility.
They are key components of a healthy
and functional spine.
Research shows that intervertebral discs
need to exchange fluid to maintain a
healthy environment, similar to how
our bodies need breathing to exchange
carbon dioxide with oxygen for our
survival. “Typically, when we wake
up in the morning we’re taller,” says
Johnson. At night when we sleep the
discs pull in fluid and they expand. As
the day goes on, that fluid gets pushed
back to the vertebra again. In this
cycle, the discs provide cushion, take in
nutrients and discharge waste products.
But when discs are injured, this process
is disrupted, cushioning is compromised
and sitting becomes difficult. “Sitting
for people with disc issues is very
uncomfortable and can be very painful,”
says Johnson.
Johnson is exploring the design of a
device that could temporarily relieve
pressure on the spine while giving
the intervertebral discs a chance to
“breathe” properly. An ideal device
would give the spine a bit of a pull, or
traction, while in a sitting posture, and
allow a person to continue working with
their arms. Johnson is leading testing
on a simulation apparatus she designed.
She uses a
stadiometer to
measure spine
height before
and after a
short period
of sitting
in traction
in order to
capture the
spinal height
changes that
result from
the discs
pulling fluid
in. Currently,
spinal traction
therapy is
available lying down with either manual
or mechanical traction, via aquatic
vertical hanging or inversion tables.
Johnson’s research aims to allow this
therapy to be made available while
sitting. This would give a patient the
chance to keep working at a desk while
receiving this type of application. She
says the focus is on helping those with
disc injuries who must sit on the job.
It could also potentially slow down the
impacts to discs from prolonged-sitting
occupations.
Johnson brings a unique background to
this research. After finishing her degree
in civil engineering at Mines, she spent
a few years in the field and then decided
to go back to school to follow a second
passion–physical therapy. She has spent
15 years as a physical therapist, and
during this time she was constantly
thinking about solutions to problems
she encountered in patients. “In the
back of my head is the engineer, the
innovator, and I need to take what I
learned at the clinic and develop these
ideas. (In order to do this) I need to
understand and speak both medicine
and engineering,” she says about the
biomedical engineering field.
Biomedical engineering is
multidisciplinary.
“You have to
know a little
about many areas
to pull in people
who are experts
in various subject
matters,” she says.
Johnson’s research
at Mines involves
backgrounds in
biomechanics,
industrial
engineering,
ergonomics,
and human
factors, including
assistance from
the University of South Dakota physical
therapy department.
Johnson is now beginning the next
phase of her research. She is set to finish
her PhD at Mines in the spring of 2019
and if all goes well, her work could turn
into a new way to help alleviate lower
back pain associated with sitting.