COMPARING THE EFFECTS OF ERGONOMIC AND STANDARD OFFICE CHAIRS ON TRUNK MUSCLE ACTIVATION.

Purpose: Musculoskeletal disorders are one of the most common health problems faced by individuals who sit for prolonged periods. The sitting design of office chairs has recently become an important aspect in preventing the musculoskeletal disorders. The aim of this study is to determine the effect of different chair types on trunk muscle activation. Material and Methods: Fifteen healthy participants (age 22.92 ± 3.40 years) were included in the study. Participants' muscle activations were assessed with the surface electromyography device while sitting and typing on the computer for 1 hour. These muscles were Thoracic Erector Spinae, Transversus Abdominus/Internal Oblique, and Upper Trapezius. Results: When two different types of chairs were compared, in the first 10 minutes, % Maximum Voluntary Isometric Contraction difference was observed only in the Thoracic Erector Spinae (p<0.05). Also, % Maximum Voluntary Isometric Contraction difference was found only in the Transversus Abdominus/Internal Oblique (p<0.05) during the last 10 minutes. No significant difference was identified in two chair types in terms of activation of Upper Trapezius (p>0.05). Conclusion: It should be considered that chair type may change the activation of trunk muscles in individuals working in a long-term sitting posture. Therefore, the use of ergonomic chairs suitable for the physiological needs of individuals should be recommended in order to encourage increased trunk muscle activation during prolonged sitting. [ABSTRACT FROM AUTHOR]