Rafael f. escamilla, PT, PhD, CSCS, FACSM1 • Clare lewis, PT, PsyD, MPH, MTC, FAAOMPT2 • DunCan Bell, MPT3 Gwen BramBlet, MPT3 • Jason Daffron, MPT3 • steve lamBert, MPT3 • amanDa PeCson, MPT3 roDney imamura, PhD 4 • lonnie Paulos, MD 5 • James r. anDrews, MD 6 Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises t he "core" has been used to refer to the lumbopelvic-hip complex, which involves deeper muscles, such as the internal oblique, transversus abdominis, transversospinalis (multifidus, rotatores, semispinalis), quadratus lumborum, and psoas major and minor, and superficial muscles, such as the rectus abdominis, external oblique, erector spinae (iliocostalis, spinalis, longissimus), t ConClusions: The roll-out and pike were the most effective exercises in activating upper and lower rectus abdominis, external and internal obliques, and latissimus dorsi muscles, while minimizing lumbar paraspinals and rectus femoris activity .