Crunches are a popular exercise that primarily targets the abdominal muscles, specifically the rectus abdominis. To perform a crunch, lie on your back with your knees bent and feet flat on the floor. Place your hands behind your head or crossed over your chest, then lift your shoulders off the ground while engaging your core. This movement helps strengthen the abdominal area and improve overall core stability. While crunches can be effective for building core strength, they should be part of a balanced fitness routine that includes other exercises for the core, back, and legs. It's important to maintain proper form to avoid strain and maximize benefits.