Use a wall as support for your feet during crunches to target all areas of the abdominal wall in a complete and comprehensive way, including the upper and lower abdominals, the obliques, and the transverse abdominis.

noli's read

Using a wall to support your feet during a crunch is an excellent variation for strengthening the abdominal wall. A study published in the *Journal of Strength and Conditioning Research* shows that flexing the hips and knees effectively deactivates the hip flexors (such as the psoas), which allows for cleaner isolation of the rectus abdominis. However, the distinction between the 'upper' and 'lower' abdominals is a misnomer, as the rectus abdominis actually contracts as a single, unified muscle sheet. Furthermore, to optimally activate the obliques, rotational or twisting movements are necessary, as a standard linear crunch remains very limited in this regard. Finally, data from the *University of New Mexico* reiterate that the transverse abdominis, a deep stabilizer, responds much better to isometric core exercises or abdominal vacuums than to trunk flexion. Thus, while this wall-based movement is ideal and safe for beginners, attributing a complete and simultaneous targeting of all these areas to it is scientifically exaggerated.

the sources

1. 1Wang XQ, Zheng JJ, Yu ZW, et al. 2012