2) Physiological cross talk
Neighboring muscles may produce a significant amount of EMG that is detected by the local electrode site.
Typically this “Cross Talk” does not exceed 10%-15% of the overall signal contents or is not available at all.
However, care must been taken for narrow arrangements within muscle groups.
ECG spikes can interfere with the EMG recording, especially when
performed on the upper trunk & shoulder muscles. They are easy to
see and new algorithms are developed to eliminate them (see ECG
Reduction).