This one has become one of my new favorite variations to the traditional plank. It can get pretty boring holding a normal plank for minutes on end. And I think these are more challenging and work a few more muscles than a normal one.
This exercise will work the inner and outer ab muscles, back, shoulders and arms.
This is another one that you should focus on quality over quantity.
First start with doing 2 x 30 seconds for each of your core sessions. Then progress into doing 3 x 1 minute of these.
Switch the arm you go down on each time. Once you try these it will be easy to remember which arm to go down with because it will be the arm you come up with.
And most importantly make sure your back is level and flat just like a board.