An Electromyographic Study of Two Different Types of Ballpoint Pens

The purpose of this study is to compare a New pen (N pen) with a conventional pen (C pen) for the load that they exert on the upper limb during 1 h of continuous writing. EMG and upper limb pain scores are used as indicators. C pen's grip area is cylindrical with an 8.3-mm diameter, and is manufactured of hard plastic, which is rigid and slippery. N pen has a cylindrical grip area that flares out at the bottom, near the pen-tip, and has a diameter ranging from 11.9-13.6mm. and the grip is constructed of a 2 to 3 mm-thick silicon rubber sleeve that is softer and less slippery than C pen. Twelve students transcribed an English text for 1 h, alternately using the two pens. The EMG of the flexor pollicis brevis and the pain scores for the thumb, forefinger, middle finger, forearm and shoulder were significantly lower for N pen than for C pen.