BACKGROUND & OBJECTIVE
This exploratory EMG study compared the trunk muscle activation patterns adopted by male subjects with a history of low back pain (LBP) provoked by prolonged sitting in 4 specific sitting postures. A previous EMG study by the lead author was performed on 14 pain-free male subjects in 2009 to which a qualitative comparison of the current findings was performed.
Subjects were 10 males with a history of LBP provoked by sitting 1-2 hours (av. age 25; height 178cm; weight 74kg). Fine wire (+/- surface) EMG data were collected from lumbar multifidus (superficial + deep), iliocostalis (lateral +medial), longissimus thoracis and transversus abdominis in the following 4 controlled stool sitting postures:
- Slump (kyphotic thoraco-lumbar -> sacrum)
- Flat (thoraco-lumbar & L/S)
- Long lordosis (extended thoraco-lumbar and L/S)
- Short lordosis (thoracic kyphosis + L/S lordosis)
EMG amplitudes were compared between postures in the LBP group, and between pain-free and LBP groups.
Muscle Activity Between Postures in LBP Group: