Evaluation of Muscle Activity of Welders in Common Welding Postures of Gas Transmission Pipelines

Many workers, especially welders, have awkward postures during their working hours. Evaluating such kind of postures is done with the aim of corrective actions. Therefore, the present study was conducted to evaluate the activity of welder's muscles in common welding postures in gas transmission pipelines.
This cross-sectional descriptive-analytical study was performed on 15 welders of the Iranian Gas Transmission Co. After the required analysis, three postures that were most used in the gas transmission pipelines were identified to evaluate muscle activity. The electromyography (EMG) activity of the erector spinae, biceps femoris, vastus medialis, gastrocnemius medialis, gastrocnemius lateralis, tibialis anterior, rectus abdominis, abdominal internal oblique, abdominal external oblique, and semitendinosus muscles are evaluated in three postures. They are analyzed based on the maximum voluntary contraction (MVC).
The results indicated that the mean of muscle activity in the kneeling posture is significantly lower than two other postures (P The muscle activity of the welders in the evaluated postures was very high. Based on the findings of this study, the muscle activity was strongly affected by the type of posture and angle of the joints, So that the muscles activity in the kneeling posture was lower than the two other postures due to the suitable angle of joints and the direct transmission of body weight.