Reverse crunches are an effective core exercise that targets the lower abdominal muscles. By lifting your hips off the ground and bringing your knees towards your chest, you engage the core and improve abdominal strength and stability.

1. Lie on your back with your hands by your sides and your legs lifted, knees bent at a 90-degree angle.
2. Engage your core and lift your hips off the ground, bringing your knees towards your chest.
3. Slowly lower your hips back to the starting position.
4. Repeat the movement.