for the journal of Ergonomics, decided to compare sitting, standing, and
perching. The goal was to analyze if hybrid sit-stand postures could prove to
be a better compromise between sitting or standing.
Normal human standing and sitting postures
are linked to the development of LBP (Low back pain) as well as discomfort when
maintained statically for prolonged periods. However, adjustments in posture
can help with relieving some discomfort. This can include taking a short break
(from standing or sitting), alternating between sitting and standing, using a
footrest, and such.
As far as the musculoskeletal aspect is
concerned, sitting and standing are quite different from one another. The
joints of the lumbar spine can be put close to the end range of flexion.
Similarly, standing can lead to positioning the lumbar spine close to its
extension. Passive tissue (including the invertebral discs) can be harmed by
Focus on Hybrid Sit-Stand Postures?
Sit-Stand Postures are also known as
Perching. They can be defined as a potential alternative to the normal sitting
and standing positions for human beings. The aim of the study was to define
three distinct postural planes (sitting, standing, and perching) to examine
muscle activations as well as ground reaction forces between them. An objective
was to see if a sit-stand posture could offer a better alternative to simply
sitting or standing.
The research consisted of 24 participants
(12 males and 12 females). Each participant completed a total of 19
one-minute-long static trials. This included sitting at 90°, standing at 180°, and
sequentially in a 5° trunk-thigh angle increments.
The collected data covered kinematics,
muscle activation levels, and ground reaction forces. A 16-bit A/D system was
used to collect all three data sets simultaneously.
were the Results?
The study determined that the perching
level was 145–175° for males, with 160–175° being for females. Furthermore, for
both biological sexes, the knee extensor activity was observed to be lower in
standing compared to the positions of perching or sitting. Take note, the anterior-posterior
forces were observed to be the highest in perching (and required approximately
15% of a person’s body-weight).
was the conclusion?
Particular chair designs can help with
sustaining an individual’s perched posture. The said chair design would aim to reduce
the lower limb demands (during perching) within a 115–170° trunk-thigh angle
for a better human experience.