In "The Yoga Toolbox" by Joseph and Lilian Le Page, each yoga pose has a corresponding affirmation.
The affirmation for Plank pose is;
"I support myself effortlessly though activation of my inner strength"
As you progress through these 30 days, remember that you are not only building up strength in your body, but you are also cultivating inner strength with your focus and determination.
The physical benefits of Plank pose are; Strengthens the legs, buttocks, back, abdominals, shoulders, arms and wrists. Plank pose is also said to improve circulation and digestion, build core strength, relieve minor tendonitis and fatigue, and energize the body while improving concentration of the mind.