Abstract
[Purpose] The present experiment was conducted to examine the effects of task difficulty load-bearing upon perception of heaviness. [Subjects] Seven healthy males participated in the experiment. [Methods] All subjects were required to hold a weight 2 times and to estimate the perceived heaviness of the weight in the first and second trials. The weight was 5% of the subject's own body weight. A simple load-bearing task (normal task: NT) was implemented in one trial and a more difficult load-bearing task (precise task: PT) in the other trial. [Results] The muscle activities recorded from biceps brachii and brachioradialis during load-bearing were not significantly different between NT and PT, whereas 5 out of 7 subjects reported that the perceived weight was heavier in PT than in NT, eventhough the load was equal in both tasks. [Concusion] The result suggests the possibility that task difficulty affects perceptions of heaviness. The possible neural mechanisms underlying the findings obtained in this study are discussed in relation to neurophysiological and brain imaging data.
