Optimal combination of auxiliary device size and its location on chopsticks for food-gripping performances.

Chopsticks are the main utensils for daily dining in Asia. Lee and Chen (2008) designed a novel auxiliary device for chopsticks that successfully converts people experienced in scissor-pinching to the correct method: pincer-pinching. This study attempts to assess the optimal combination of auxiliary size and location on chopstick stems for food-gripping performance. Twenty-four male participants experienced in scissor-pinching were recruited for the experiment. They were requested to perform 3 simulated tasks (force, precision, and stability) using 6 auxiliary combinations of 3 sizes (15, 25, and 35 mm) of chopsticks and 2 locations (on top of the stems and 1/3 stem-length from the top). Results indicate that auxiliary device size influenced simulated task performance and the user's subjective rating of chopsticks use. The auxiliary device measuring 15 mm wide showed the best performance in pinching force, precision, stability, and subjective rating. The location of the auxiliary device only affected the pinching force. The auxiliary device produced greater force when located at the top of the stems. This finding improves the application of auxiliary devices to chopstick operation.