The rectus abdominis is a long flat muscle which runs the length of the abdomen. Due to the bumps of the tendinous inscriptions, the muscle is often referred to as the “six pack”. Working with its neighbours, the obliques and transverse abdominis, the muscle works to stabilise the trunk and also flex it forward.
Typical exercises which dynamically target the rectus abdominis include crunches, v-ups, hanging leg raise and the roman leg raise. These exercises recruit the muscle to flex the spine, shortening the distance between the ribcage and pelvis.