Fig. 4

User interface. a Task for data collection. Participants were asked to perform the gestures shown by the graphical user interface and follow the muscle activation profile (blue line) by producing two sustained contractions with plateaus at 30% and 60% of the MVC for the respective gesture. The contraction level was estimated as the root mean square of windowed EMG across all the channels and provided as feedback to the user (green line). b Online test interface. Participants were asked to match a target gesture and wrist position while the predicted gesture was shown on the side. The task was considered successful if the subject matched the right gesture for two consecutive seconds while maintaining the contraction level inside the range indicated by the corresponding pair of dashed lines (i.e., low or moderate)