Fatigue problems in remote pointing and the use of an upper-arm support

Abstract

Remote Gesture Pointing (RGP) has been developed as a means for controllers to perform pointing operations when the controller of a device is required to move about during the task and is not normally stationed at a fixed location. Some devices in RGP environments have been developed for such purposes, but to date little research has been reported. To contribute to addressing this issue, our study examines the muscle fatigue problems in RGP environments and proposes an orthopedic appliance (which supports the upper arm) to resolve such problems. Twelve healthy subjects participated in the experiment, which had three conditions (General Mouse Pointing (GMP), RGP with an upper-arm support ('RGP with support'), and RGP without an upper-arm support ('RGP without support')). Participants performed the multi-directional tapping tests for each condition. The experimental results indicated that the effects of time on the fatigue indexes (from each the upper trapezius and the anterior deltoid) was more prominent in the 'RGP without support' condition than in the other conditions. Especially in the 'RGP without support' condition, each of the fatigue indexes after 30 min became significantly different with the corresponding initial values. Similarly, the subjective fatigue scores showed a common pattern in the 'RGP without support' > 'RGP with support' > 'GMP' order in all parts (shoulder, upper arm, forearm, and wrist and hand). The overall performance of the RGP conditions was much lower than that of the GMP condition. Also, the throughput value was significantly higher in 'RGP with support' than in 'RGP without support'. These findings show that RGP has potential fatigue and poor performance problems and an orthopedic appliance supporting the upper arm can be an alternative to alleviate those problems of RGP environments to some extent. Future work is necessary to further develop an orthopedic appliance in real situations. Relevance to industry: The method and the experimental findings in this study can be utilized as the bases for developing an orthopedic appliance to alleviate the fatigue and performance problems in real RGP environments. (C) 2012 Elsevier B.V. All rights reserved.