Fig. 2
From: Myoelectric interface training enables targeted reduction in abnormal muscle co-activation
Calculating the disparity index (DI). From the synergy set of the baseline week, the synergy with the highest co-activation (lowest difference) between the targeted muscle pair (e.g., BI and AD in the second synergy (dark gray); m1base and m2base, their muscle weights) is identified. Both m1base and m2base are higher than ThCoA, the threshold of muscle co-activation. The synergy at week 6 (the second synergy of week 6) corresponding to the synergy of the baseline week is selected by calculating the scalar product with the baseline synergy 2. DI is calculated (right) from m1 and m2 at both time points, as the distance from the mean of m1 and m2 (Eq. 3). Finally, the change in the muscle weight disparity after training (ΔDIpost-training in red) is obtained by subtracting DIbase from DIwk6