Here's Your Exercise Encyclopedia For Toned Arms and Tight Abs

• Begin in a full plank. Lower your right elbow to the mat and then your left, coming into an elbow plank.
• Put your right hand on the mat, and straighten your right elbow. Do the same on the left to return to a full plank.
• Do 10 reps starting with the right arm, the do 10 leading with the left arm.

Your arms will burn after this exercise, but your abs are still working — they keep the torso stable while moving between elbow plank and full plank.