The long lever plank variations resulted in higher external oblique muscle activity compared to the standard plank variations, irrespective of posterior pelvic tilt. (strengthandconditioningresearch.com)
There was a trend towards greater external oblique muscle activity in the long lever plank with posterior pelvic tilt compared to the long lever plank without posterior pelvic tilt (148 vs. 111 % of MVC). (strengthandconditioningresearch.com)
They reported higher external oblique muscle activity in the stable floor condition compared to the other conditions. (strengthandconditioningresearch.com)