If you're trying to get a six pack or flatten your abs, one of the hardest places to get to show is your lower abs. One way to help them show through is to work them during your ab workouts with great intensity. This will build the muscle up and help them show through.

Strengthening your lower abs is also a very important part of building a strong core that will safeguard your body. Remember, it's important to work your entire core, and not just focus on a single part.

To get a great lower ab workout, you should focus on ab exercises that mostly concentrate on moving your legs. Here are three lower ab exercises that you can incorporate into your workouts immediately to give you some variety.

1. Hanging Leg (or knee) raises - This ab exercise is one of the best that will help you gain strength in your lower abs relatively quickly because of the weight you will be moving (your legs weigh a lot!).

To do this exercise, hang from a pull up bar and lift your legs all the way up to a vertical position. If you can't do this quite yet, start by tucking your legs and lifting your knees as high as you can.

2. Decline bench leg thrusts - Lay on a decline bench with your head higher than your legs. Hold onto the bench with your hands and bring your legs up vertical, then push them into the air straight up. Bring them back down and lower them back to the starting position for one rep.

3. Stability ball knee tucks - This exercise is one of my favorites and will give you a killer lower ab workout. Start with your shins on a workout ball and and your hands on the ground (push up position). Bring your legs toward your body and stick your butt in the air. Then go back down for one rep.

When doing all three of these exercises, be sure to focus on your form. You never want to arch your lower back or use momentum. Always use a controlled movement so you don't hurt yourself!