Development of the Strength Level on Arm for Indonesian People in Lifting Activity

Lifting is one of manual material handling activity that involves the whole part of a body. This activity is significant to contribute musculoskeletal disorder specifically on arms. It is because the arms are a major strength to lift objects. However, many people do not know the capability of their arm so that the task designed does not comply with the limitation of workers. Thus, it is required to determine a level of strength on arms. The objective of this study is to develop the strength level of arms for Indonesian people based on musculoskeletal contraction. An experimental study is conducted in the ergonomics laboratory. 24 males and 24 females was participated in this study which consists of three different ethnics. They are sixteen participants of Ethnic A, sixteen participants of Ethnic B and sixteen participants of Ethnic C. A case study of lifting consists of 4 positions of object. They are 38 cm in height, 50 cm in height, 85 – 115 cm in height for forming 90 degrees of the elbow and 100 cm in height. Back lift technique was implemented. An Electromyography is used to investigate muscle contraction on arms. Statistical analysis is done to test the hypothesis. The result of this study shows that the arm strength level for Indonesian workers has significant differences between males and females among difference Ethnic. For male, Ethnic A has 28.82% - 79.28% of MVC, Ethnic B has 17.74% - 58.67% of MVC, and Ethnic C has 22.13% - 68.67% of MVC. For female, Ethnic A has 28.28% - 84.63% of MVC, Ethnic B has 24.47% - 70.98% of MVC, and Ethnic C has 24.24% – 75.67% of MVC.