Investigation of effects of ways of using muscles on performance of fine handwork

To improve the performance of fine handwork, we investigated how muscles should be used in 9 examinees. A given task was how many pushpins each examinee sitting at a table was able to transfer from a dish to a taller cup in 10 seconds using a pair of chopsticks. How to use the muscles relating to the handwork was determined by measuring the electrical activities of muscles at three points such as the shoulder, the radial and ulnar sides in the forearm. Then, multiple regression analysis revealed that activation of the shoulder muscle and the aberrant ways of holding chopsticks deteriorated the performance significantly and also that activation of muscle on the ulnar side (little finger side) in the forearm and the normal and near-normal ways of holding chopsticks improved the performance significantly. In conclusion, to improve the performance or to show one´s full abilities, it is important to hold and handle a tool very gently by relaxing the shoulder, thumb and forefinger as much as possible during fine handwork.