Figure 2.

Bipolar surface electromyographic electrode and wireless sensor placement. (A) Rectus Abdominis: parallel to the rectus abdominis muscle fibers and approximately located 3 cm lateral and across from the umbilicus over the muscle belly. (B) External Oblique: parallel to the external oblique muscle fibers and approximately located 15 cm lateral and across from the umbilicus. (C) Internal Oblique: parallel to the internal oblique muscle fibers and halfway between the anterior superior iliac spine of the pelvis and the midline, just superior to the inguinal ligament. (D) Erector Spinae: approximately 3 cm from the L3 spinous process, over the muscle belly and parallel to the erector spinae muscle fibers.