where does the axial musculature insert
These sits-ups, along with other similar exercises, work our oblique (that is, not straight) as well as our rectus (or straight) muscles located in the body wall of our trunk. These oblique and rectus muscles are axial muscles as they're located in the middle, or the axis, of the body. Most people will think of trunk muscles as being located anteriorly (that is, in the front) in the belly area of the abdomen.