The Plank is a popular core-strengthening exercise that targets the abdominal muscles, back, and shoulders. To perform the plank, an individual lies face down and then lifts their body off the ground, balancing on their forearms and toes. The body should form a straight line from head to heels, engaging the core to maintain stability. This exercise can be modified in various ways to suit different fitness levels. For beginners, a knee plank can be performed by resting on the knees instead of the toes. Advanced variations include side planks and plank jacks, which add difficulty and engage additional muscle groups.