Seated Postures Linked to Different Muscle Activities
Electromyography shows combinations of muscle activity associated with three upright postures
MONDAY, March 30 (HealthDay News) -- The use of electromyography provides helpful details regarding the regional muscle activity that occurs during three sagittally balanced seated postures, according to research published in the March 15 issue of Spine.
Andrew P. Claus, of the University of Queensland in Brisbane, Australia, and colleagues analyzed data from 14 healthy males who underwent electromyography of nine spinal extensor and abdominal muscles while sitting in three sagittally balanced postures (flat, long lordosis, short lordosis) and a slumped position.
In the three balanced postures, activity of the superficial and deep lumbar multifidus fibers increased incrementally, the researchers report. Of the balanced postures, the flat posture demonstrated the lowest muscle activity, which in most muscles was similar to the slumped position.
"The results provide new detail to distinguish between sagittally balanced postures. Subtle changes in thoracolumbar and lumbar spinal curves in sitting are associated with varying magnitudes of muscle activity, particularly in the deep and superficial regions of lumbar multifidus. The highest activity levels at multifidus and obliquus internus abdominis muscles occurred in the short lordosis posture. The lowest activity levels were observed at most muscles in the flat posture," the authors conclude.