Effectiveness of a new working tool for plaster ceiling job based on fatigue measurement

Abstract

Fatigue can be used as a measure for evaluating the effectiveness of ergonomic interventions. Furthermore, the risk of musculoskeletal diseases increases in fatiguing work. With the purpose of reducing given extreme postures musculoskeletal disorders (hands above head, raised shoulders, and neck bent backward) an alternative working tool for plaster ceiling job was introduced. The new tool has an extended handle that enables to work with hands about hip level. The new tool also utilizes a spring for a better plastering. To evaluate the effectiveness of the new tool, a within-subject experiment was conducted. A total of 24 participants (age 20-60 years old) were involved. They were recruited among professional workers who simulated plaster ceiling work for two hours. Fatigue development was measured through changes in: Rate of Perceived Discomfort (RPD) using the Borg scale, Hand grip strength, Heart rate, Blood pressure and Maximum Voluntary Contraction (MVC) of the middle deltoid muscle. The data was collected every 20 minutes, and then changes in measures overtime were then analyzed. The results showed that plastering with the new tool was less fatiguing than the traditional too (p <;0.001). In addition RPD seemed to be the most sensitive fatigue measure followed by declines in hand grip strength, MVC reduction and changes in heart rate. In conclusion, the new working tool was more effective and can be used in construction work. The methods used in this study can be applied in evaluating the effectiveness of ergonomic interventions that have an effect on the physical workload.