STOMACH VACUUM OR FLEXED ABS
Stomach Vacuum Or Flexed Abs
The vacuum method allows for a broader shoulders base and lat spread, while the abdominal crunch method is impressive if your midsection is ripped. You should do the variation which you feel makes you look the best overall.
A way to do both variations during the double biceps pose is to begin in the vacuum position, then at the finish of the pose, exhale and crunch those abs before moving on.