Figure 7.

The EMG responses of the right and left rectus abdominis muscle and right and left rectus femoris muscles. A single lead approach was adopted for MI (−0 and +3) and M5 (−4 and +7) with a frequency of 2 Hz, pulse duration of 240 µs, and 6 volts. EMG sensors were placed at the distal 1/3 of the rectus abdominis. It is worth noting that there was no EMG activity detected below 6 volts. M1 resulted in a reasonable isolation of the rectus abdominus muscles from the rectus femoris muscles whereas M5 resulted in bilateral stimulation of the rectus femoris muscles with activation of the rectus abdominis muscles.