The plank is a foundational core exercise that strengthens the entire abdominal region, including the rectus abdominis, transverse abdominis, and obliques, as well as the muscles of the lower back and shoulders. To perform a plank, start in a push-up position with your hands directly under your shoulders and your body forming a straight line from head to heels. Engage your core muscles to keep your body stable and hold this position for as long as you can while maintaining proper form and breathing rhythm. Avoid sagging your hips or raising your buttocks too high. Planks are effective for improving core strength, stability, and endurance, and they can be modified by performing them on your forearms or incorporating variations such as side planks or plank with leg lifts to further challenge different muscle groups.