The core consists of the muscles that stabilize and support your spine, and includes the muscles of the back and the abdominal region. Developing a strong core is important because these muscles support the entire body, in both exercise and activities of daily living.
The plank, in particular, is effective because it targets the core as a whole and engages multiple additional muscle groups. It also can be performed anywhere without additional equipment, and is modifiable to varying fitness levels.
Once you have mastered the basic plank, give these five variations a try. For each exercise, aim to complete a set number of repetitions or perform the exercise for a set amount of time. When performed consistently, these exercises will help you create a stronger, more stable core.