Before the experiments, the skin of each subject was cleaned using an alcohol cotton ball to remove foreign substances at the electrode adherence point, after which markers were attached. Six electrodes were attached to the FCU (flexor carpi ulnaris), FCR (flexor carpi radialis), ECU (extensor carpi ulnaris), ECR (extensor carpi radialis), and both UT (upper trapezius) muscles.
To measure muscle activation, the sampling frequency for electromyography signals was set to 1,000 Hz. Electromyography signals entering through the six channels were collected, root mean square (RMS) values were calculated, and the values were then normalized as ratio maximal voluntary isometric contraction (MVIC and %MVIC. For each muscle, MVIC was measured three times, and the average was calculated. Each task was performed three times, and the measured values were used to calculate the MVIC and %MVIC.
The writing items were the 7 subtests of the Jebsen-Taylor Hand Function Test10, 11). The collected data were analyzed using SPSS for Windows for frequency, and the differences were examined using an independent t-test