Sit-ups are a common exercise used to strengthen the abdominal muscles. To perform a sit-up, an individual lies on their back with knees bent and feet flat on the ground. They then lift their upper body towards their knees while keeping their hands behind their head or crossed over their chest. This movement engages the core muscles, helping to improve overall stability and strength. Sit-ups can be part of a broader fitness routine that includes other exercises for different muscle groups. They are often included in workouts aimed at enhancing athletic performance or improving posture. However, proper form is essential to avoid strain on the back and neck.