Ergonomics and the usability of mechanical single-channel liquid dosage pipettes

Evaluation of Ergonomics and Efficacy of Instruments in Dentistry

“…During the MVC of the m. flexor pollicis brevis, the participant placed her elbow on the table at a flexion of 100-110° while holding a scaling instrument in her hand. She then maximally pressed the handle of the instrument [17]. During the MVC of the m. extensor digitorum and m. flexor carpi radialis, the participant's forearm was in pronation and supination, respectively, on the table, and she raised her hand (in the direction of wrist extension and flexion, respectively) against the researcher's resistance on the dorsal side and volar side of her hand.…”

“…The amplitude of the MVC ( V) was calculated after the participant had reached the peak level of contraction and held it for 3-4 seconds. The muscle contraction and EMG amplitude level remained stable during the test for maximal isometric contractions, which was one criterion for choosing the maximal EMG activity as a reference [17].…”

“…The output from the goniometer was sampled with a data logger (ME6000, Mega Electronics, Kuopio, Finland) at a frequency of 1000 Hz, using the averaged mode and a time constant of 0.1 second. From the electrogoniometer data, the mean values of degree (°) were analyzed [17,21].…”

“…The wrist and lower-arm movements were measured using a twin-axis electrogoniometer and a single-axis torsiometer, respectively. The upper-arm ranges of motion were registered using an inclinometer (Biometrics Ltd, Cwmfelinfach, UK) [17,21]. The sensors were attached to the back of the wrist with skin adhesive tape.…”

“…VASs were also used to evaluate the perceived musculoskeletal strain in six body parts (neck, shoulder, upper arm, lower arm, fingers/palm, thumb) [14][15][16][17].…”