Plank | Anatomical Analysis This great exercise intended to strengthen our core muscles. We must maintain a straight back (neutral spine) throughout the entire range of motion. The abdominal muscles stabilize the chest from the top and the pelvis from the bottom. Contraction of the abdominal muscles (and especially the transversus abdominis) increases Intra-Abdominal Pressure (IAP), thus preventing pressure on the lower vertebrae. The scapulae are stabilized by the serratus anterior muscle. When