Planking

[boxerbilly]

GAY .................................................. .................

But thats okay.

[David Jamieson]

3 x daily 90 secs each time.
It's a great core exercise.

Chaturanga posture is also acceptable as it is adding chest and shoulders to the core. (when you are at the down point in a push up without touching the floor)

[highlypotion]

Looks easy but extremely hard when done.

[shanghai-mantis]

and I thought I was hardcore for doing 20 minutes once