Application of wearable technologies for the assessment of biomechanical risk in hairdressers

Abstract: It is usual to link respiratory and skin health issues to hairdressing job. The most current papers from throughout the world reported on biomechanics as well. Shoulder, lower back, and upper back joints were the most impacted. Several authors conducted ergonomic risk assessments through standardized protocols, like REBA, founding high-risk levels. Other authors measured shoulder and wrist movement with IMU or inclinometer founding a high biomechanical risk. Only one study used electromyography (sEMG) to compare the activity of male and female hairdressers founding those women had considerably higher sEMG activity. This study only measured the muscle work from upper limb flexors and extensors. To our knowledge, no research has investigated the whole upper body kinematics and sEMG from the upper arm, shoulder, and trunk using instrumentally based tools for hairdressers’ risk assessment. The aim of our study is a biomechanical risk assessment of the subtask of hair drying in two different ways (horizontally – HOR and upwardly - UP). We acquired four expert workers using an optoelectronic system and sEMG. sEMG results showed that the left side of the body was generally more involved than the right one in both the assessed tasks. Latissimus Dorsi, Trapezius Superior, Deltoideus Anterior, and Flexor Carpi Ulnaris were severely affected by this. In the UP task, the shoulders (Trapezius Superior and Deltoideus Anterior) had high mean percentage of Maximum Voluntary Contraction (%MVC) values. According to our sEMG results, holding a phone that weighs almost 1 kg in a static position is less straining on the upper limb and shoulder than constantly moving the left hand while holding a small comb. Kinematic data seems to support this. The left side showed the highest Range of Motion (RoM) values than the right for shoulder abd-adduction and elevation on the UP task and shoulder horizontal abduction, elbow flex-extension, and wrist prono-supination on both tasks. The shoulder flex-extension showed comparable high RoM values in both tasks.Our findings also show a high standard deviation for RoMs, indicating a high heterogeneity in performing the same task. Our research found that hair-drying is a demanding task for hairdressers. We recommend using wearable technologies to have a more reliable work situation instead of standardized protocols for risk assessment.

Keywords: ergonomic, electromyography, biomechanical overload

DOI: 10.54941/ahfe1003623

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