Laptops PC have been in widespread use in the past decade. Stewart (1997) has reported that the prevalence rates of musculoskeletal disorders associated with laptops were even higher than traditional desktop PC. Tablet PC is one kind of portable PC. From ergonomic viewpoint, the users who hold the tablet PC with weight between 1.4 kg to 1.95 kg and without supporting are obviously in high risk of static sustaining posture. Therefore, the current study will evaluate the tablet PC in the laboratory by employing a simulated physician？？s ward inspection task. A tablet PC with two kinds of weight (1.4 kg and 1.95kg while keyboard attached) and one desktop PC as the control were evaluated in the present study. Thirty students (15 males and 15 females) from one medical university participated voluntarily. EMG and motion analyzer were employed to assess the dynamic muscular loads and posture settings. Besides, a questionnaire was used to evaluate the subjective discomfort after each session of experiment. A mix design multiple factorial analysis of variance with repeated measures was employed. Gender was treated as between subject factor. Types of PC, ways of holding tablet PC (vertical screen and horizontal screen), and sessions of experiment were treated as within subject factors. The results of EMG data showed that different genders and weights of Tablet PC resulted in significantly differences. The average %MVC values for female are significantly higher than males. The %MVC value for female on the muscle biceps brachii (11.85) and the flexor carpi (8.81) of the left hand which responded for holding the tablet PC and the muscle flexor dogitorum superficialis of right hand for handling digit pen were found as the highest ones. Besides, significantly higher %MVC values were also found while utilizing tablet PC with larger weight compared with the lighter condition especially on the muscle flexor carpi of left hand. As for the evaluation of subjective discomfort, left hand (including upper and forearm) that holding the tablet PC was rated as the severe discomfort body part which may be attributed to the weight of tablet PC. Furthermore, larger forwards bending neck angles and viewing angles which exceeded the general recommended 15-30 degree were also reported. The user interface is quite user-friendly for the tablet PC. However, for the current employed tablet PC which weights 1.4 to 1.95kg, the muscular loads were obviously higher compared with using general VDT task for using desktop PC. Besides, larger forwards bending neck angles and viewing angles were also found. Therefore, limited continuous using time is recommended for the experiment tablet PC Besides, the major inputting icons and buttons are suggested to be set up on the top of tablet PC which will reduce over upper arm abduction and muscular load.
