Comparing Muscle Activity and Spine Shape in Various Sitting Styles

Erik Peper, Björn Krüger, Esther Gokhale, and Richard Harvey
In: Biofeedback (2019)
 

Abstract

Back problems affect 80% of the population in the U.S. at some time during their lives, and each year 32 million Americans experience lower back pain at an estimated economic cost of 560-635 billion. One contributing factor for back pain is posture, and more particularly, lack of awareness of dysfunctional posture. For example, many people may sit in a slouched or forward-bent position, exacerbated by poor ergonomics while sitting or, extended use of handheld digital devices while standing such as looking down at a smartphone for long periods of time. This report describes a ‘stacksitting’ technique which is one of the components of the Gokhale Method® for healthy, relaxed sitting and increased awareness of posture. The stacksitting process is illustrated with a case study where the shape of the spine and the muscle activity is analyzed in parallel during three sitting styles: slouching, arched, and stacksitting. The spine curvature was characterized by the Gokhale SpineTracker™ wearable, which consists of five sensor-units attached along the subjects’ spines that are used to plot the spinal curve on a digital device such as a smartphone, tablet or computer. SEMG recordings were made from the right upper trapezius, left upper trapezius, right mid-back, and left mid-back with a second device (Myoscan Pro sensors recorded with Biograph Procomp Infinity) while participants were seated in three postures: a slouched (forward-bent) position, an upright ‘arched’ position, and an upright ‘stacksitting’ position as trained by a Gokhale Method teacher. The case observations showed no significant difference in trapezius SEMG activity during each of the three positions. There was a slight increase in SEMG activity of the mid-back during stacksitting (1.1 µV) as compared to when slouched (0.64 µV) and, a significant increase in SEMG activity when sitting arched (4.9 µV). As expected, the spinal activity tracking device showed significant straightening of the lower spine during the stacksitting position as compared to the slouched and arched positions. The observations suggest that the stacksitting position can be taught to others in a way that allows the vertebrae to be parallel to each other with very low levels of corresponding muscle activity. In contrast, sitting in an arched or slouched position would increase asymmetrical pressures on the disks, contributing to vertebral wedging which could also contribute to spinal disk-bulging and eventual back injury. The observations suggest that proper coaching may foster a stacksitting position of the spine, which would foster a healthier posture than a slouched or arched spinal positions.

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Bibtex

@ARTICLE{peper-2019-a,
    author = {Peper, Erik and Kr{\"u}ger, Bj{\"o}rn and Gokhale, Esther and Harvey, Richard},
     title = {Comparing Muscle Activity and Spine Shape in Various Sitting Styles},
   journal = {Biofeedback},
      year = {2019},
      note = {accepted for publication},
  abstract = {Back problems affect 80% of the population in the U.S. at some time during their lives, and each
              year 32 million Americans experience lower back pain at an estimated economic cost of $560-$635
              billion. One contributing factor for back pain is posture, and more particularly, lack of awareness
              of dysfunctional posture. For example, many people may sit in a slouched or forward-bent position,
              exacerbated by poor ergonomics while sitting or, extended use of handheld digital devices while
              standing such as looking down at a smartphone for long periods of time. 
              This report describes a ‘stacksitting’ technique which is one of the components of the Gokhale
              Method® for healthy, relaxed sitting and increased awareness of posture. The stacksitting process
              is illustrated with a case study where the shape of the spine and the muscle activity is analyzed in
              parallel during three sitting styles: slouching, arched, and stacksitting. The spine curvature was
              characterized by the Gokhale SpineTracker™ wearable, which consists of five sensor-units attached
              along the subjects’ spines that are used to plot the spinal curve on a digital device such as a
              smartphone, tablet or computer. SEMG recordings were made from the right upper trapezius, left upper
              trapezius, right mid-back, and left mid-back with a second device (Myoscan Pro sensors recorded with
              Biograph Procomp Infinity) while participants were seated in three postures: a slouched
              (forward-bent) position, an upright ‘arched’ position, and an upright ‘stacksitting’
              position as trained by a Gokhale Method teacher.  The case observations showed no significant
              difference in trapezius SEMG activity during each of the three positions. There was a slight
              increase in SEMG activity of the mid-back during stacksitting (1.1 µV) as compared to when slouched
              (0.64 µV) and, a significant increase in SEMG activity when sitting arched (4.9 µV). As expected,
              the spinal activity tracking device showed significant straightening of the lower spine during the
              stacksitting position as compared to the slouched and arched positions. The observations suggest
              that the stacksitting position can be taught to others in a way that allows the vertebrae to be
              parallel to each other with very low levels of corresponding muscle activity. In contrast, sitting
              in an arched or slouched position would increase asymmetrical pressures on the disks, contributing
              to vertebral wedging which could also contribute to spinal disk-bulging and eventual back injury. 
              The observations suggest that proper coaching may foster a stacksitting position of the spine, which
              would foster a healthier posture than a slouched or arched spinal positions.}
}