BACKGROUND: Measurement of hand exertion is very important to quantify the risk of Work-related Musculoskeletal Disorders (WMSDs) in manufacturing fields. Although a direct measurement is the most accurate way to quantify physical load, it is expensive and time consuming. To solve this limitation, a subjective self-report method has been proposed as a possible alternative. OBJECTIVE: The purpose of this study was to analyze the accuracy of subjective perception for grip force exertions associated with handedness (dominant and non-dominant hands). METHODS: A total of nine healthy adults participated in this study. All participants were asked to exert hand grip forces for randomly selected target force levels without any information about the actual target force levels. Then, participants were also asked to rate the subjective perception of their exertion level using % Maximum Voluntary Contraction (MVC) after each hand grip force exertion. RESULTS: The trend of subjective perception for various target force levels was different according to the handedness. In the case of the dominant hand, participants tend to rate less MVC levels (under-estimation) than the actual target force levels at lower than 50% MVC, whereas they tend to rate more MVC levels (over-estimation) than the actual target force levels at higher than 50% MVC, respectively. In case of non-dominant hand, generally participants showed over-estimate for all levels of MVCs in this study. CONCLUSIONS: According to the results of this study, subjective perception of exertion showed different patterns on the handedness (S-shape for dominant hand vs. over-estimation for non-dominant hand) for various target force levels. Therefore, it would be necessary to apply different criteria for each hand to evaluate subjective perception of hand grip exertion tasks.
