Background: Different postural positions can be characterized by the activation and relative contributions of different postural muscles, and may variously contribute to the recovery from or worsening of chronic lower back pain.
Objective: The present study aimed to investigates trunk muscle activities in four types of seated postures: cross-legged, long, side, and W-shaped.
Methods: Eight healthy adults participated in the study. Trunk muscle activities of the external oblique (EO), rectus abdominis (RA), latissimus dorsi (LD), and erector spinae (ES) muscles in each of the sitting postures including cross-legged, long, side, and W-shaped were collected utilizing surface electromyography (sEMG). The mean sEMG signals in each of the sitting postures were used for statistical comparisons.
Results: There were no significant differences in electromyographic muscle activity of EO, RA, LD, and ES in the four postures (p > 0.05). However, in the W-shape sitting posture, the left LD showed the greatest electromyographic muscle activity, followed by the right LD and left EO, respectively. The right and left LD in the long sitting posture and left ES in the side sitting posture showed greater electromyographic muscle activity than that of other muscles.
Conclusion: Based on the results, trunk muscle activity did not significantly differ between the four types of sitting postures. However, our study is limited by its experimental method and sample size. Thus, in the Future, further study will be needed.
Keywords: Electromyographic activity; sitting posture; trunk muscle.