hey, your elbows and arms should get used to it.
you know, i used to think that plank was a critical move. i still consider it far, far more useful than crunches, which are stupid. but i don't think it's critical anymore, if you're training right otherwise.
between deep squats and pull-ups, i think the core is trained totally adequately. if you keep your legs in front of you during pull-ups and keep your abs tensed, i actually consider them to be one of the best ab exercises, period. also, overhead pressing demands a tight mid-section.
i guess the longer i train, the more i question the need for any direct ab work. compound movements really take care of it.
"dean ornish and dr. davis think the palmitic acid our bodies use for fuel while we sleep is poison if we eat it. zero-carbers like charles washington think the oldest fuel in our evolutionary history – glucose - used by organisms a billion years ago and without which the brains of modern mammals cannot survive for more than a few minutes – is an unnatural toxin if you eat it. both views ignore basic facts of medical physiology and defy evolutionary history." - kurt harris