The Plank is a great all-around exercise that can help to provide strength and stability to your core. So many muscles and muscle groups are worked while doing a plank and it is another great exercise that you can do at home, when you are travelling or even in the evening as you relax in front of the television.
The three major muscles worked by doing the plank are the erector spinae, rectus abdominis and tranverse abdominis. The secondary muscle groups worked during the plank include: traps, rhomboids, rotator cuff, deltoid, pecs, serratus anterior, glutes, quads, gastrocnemius (calf muscle). As you can see, this simple exercise is a great way to help you strengthen your core and work a lot of muscles at once.