20 best lower-ab exercises for a rock-solid core

When people think of a strong core, they often think of a six-pack in the middle or the sculpted lines that run down the sides, but in reality, achieving rock-solid abdominals involves working every layer of muscle in your core, including your lower abs.

You see, your core is made up of three major muscles: the rectus abdominis (the muscles that run down the front of your body and create a six-pack effect); the obliques (the muscles along your sides); and the transverse abdominis (the deepest layer of ab muscles that corset the waist and support the hips).

So when it comes to strengthening the lower abs, what you're actually strengthening is the lower part of your rectus abdominis. Having strong lower abs can help make everyday activities, like walking and running, much easier. And if you suffer from low-back pain and poor posture, working out your lower abs can be particularly beneficial for you.

"When you have a weak core, hyperlodosis-the unnatural arching of the lower back-can occur. Strong abs help stabilise the spine," says personal trainer Larysa DiDio. "Also when abs are weak, the hips can tighten to over compensate for too much back mobility and not enough support when performing an activity."

That said, you can't isolate your lower abs when you're working your core, but there are exercises that help target and activate those muscles more than others. The exercises below-designed by DiDio-help you engage your lower abs, while tightening every other cemtimetre of your core. It's important to note that a common mistake people often make with lower-ab exercises is that they end up working their hip flexors instead of their lower abs because of improper form.

To fix this, Didio suggests, "Pull the belly button to the spine-towards the floor-when doing these exercises and avoid letting your abs puff out."

Time: 40-60 minutes

Reps: 8-12 reps for 3 rounds

Equipment: A pair of gliders or small hand towels and a yoga mat

1. Crunches

How to do crunches: Lie face up on a yoga mat with your low back firmly pressing on the mat and your knees bent at 90 degrees in tabletop position, stacked above your hips. Place your hands behind your head with your shoulders lifted off the mat and crunch up and then bring your shoulders back down. This is one rep.

Pro tip: Engage your abdominal muscles to lift your head and shoulders up to avoid pulling on your neck. And remember to breathe—many people tend to hold their breath throughout the movement.

2. Crunch with leg extension

How to do crunches with leg extension: Lie face up on a yoga mat with your low back firmly pressing on the mat and your knees in tabletop, stacked above your hips. Place your hands behind your head with your shoulders lifted off the mat. Crunch up. As you bring your shoulders back down, extend your legs out straight in front of you. This is one rep.

Pro tip: Use your abdominals to keep your head and neck lifted. If your neck feels strained, omit the crunch and keep your shoulder blades lifted off the mat as you extend your legs out.

3. Deadbug

How to do a deadbug: Lie face up on an yoga mat with your arms extended towards the ceiling, and your legs in tabletop position and stacked above your hips. Moving with control, extend your right leg out to straighten, while bringing your left arm behind you overhead. Keep your arm and leg hovering a few inches off the ground. Then, bring your arm and leg to the starting position and repeat on the other side. This is one rep. Be sure to engage your core throughout the entire movement.

Pro tip: This exercise focuses on balance as much as it is about strengthening the core. Move slowly to maintain coordination and truly engage your abdominals.

4. Scissors

How to do scissors: Lie face up on a yoga mat with your low back firmly pressing on the mat. Extend your legs straight out in front of you and place your hands behind your head with your shoulders lifted off the mat. Engaging your lower abs, alternate lifting one leg up toward the ceiling while the other one lowers to hover over the mat. Lifting each leg once counts as one rep.

Pro tip: Be sure to keep your shoulder blades lifted throughout the entire movement and avoid arching your low back to truly target your low abs.

5. Bicycle crunch

How to do a bicycle crunch: Lie face down on a yoga mat with your lower back pressed onto the mat. Place your hands behind your head with your shoulders lifted off the mat, and your knees in toward your chest. Then, straighten your left leg out, and twist your upper body to bring your left elbow to meet your right knee. Repeat on the other side. This is one rep.

Pro tip: Move quickly—but with proper form—to make it a cardio exercise.

6. Runner's crunch

How to do a runner's crunch: Lie face up on a yoga mat with your elbows bent at 90 degrees, resting on the the mat. Engaging your lower abs, roll up to sit while bringing your left knee to meet your right elbow, mimicking the motion of running. Then, with control, slowly straighten your leg as you peel down towards the mat until you're back in the starting position. Repeat on the other side. This is one rep.

7. V-sit ups

How to do V sit-ups: Lie face up on a yoga mat with your arms overhead behind you and your feet lifted off the mat. Keep your shoulders and head off the mat as well. Engaging your core, roll up to bring your hands toward your feet.

Pro tip: If you can't quite do a V sit-up, keep your knees in tabletop position instead of extended and slowly roll your torso up to your knees.

8. Split V seat into leg drop

How to do a split V seat into leg drop: Lie face up on a yoga mat with your arms extended behind you overhead and your legs lifted off the mat. Engaging your core, slowly bring your arms toward your chest, lifting your shoulders off the mat. Then, lower your legs toward the mat until they're hovering above the mat. Pause for a moment and then bring your legs and arms back to the starting position.

9. Pilates 100

How to do the Pilates 100: Lie face up on a yoga mat with your arms straight by your sides and your legs lifted, feet up towards the ceiling. With your arms by your side, shoulders off the mat, and a tight squeeze between your legs, start pumping your arms up and down, engaging your triceps and inhaling and exhaling for five seconds each 10 times—that's why it's called the 100.

Pro tip: To modify, bring your legs to tabletop so your knees are bent at 90 degrees and stacked over your hips.

10. Boat pose

How to do boat pose: Sit up on a yoga mat with your knees bent and feet flat on the floor. With your legs together, lift your feet off the mat, forming a 45-degree angle to your torso. Extend your arms straight out in front of you so that they're parallel to the mat. Keeping your core tight and your back flat, balance on your tailbone. Then, straighten your legs out to a 45-degree angle. Hold and then bring your legs back to the starting position.

11. Plank rock

How to do a plank rock: Get into a forearm plank with your shoulders directly under your elbows and your hands facing forward. Your body should be in a straight line from the top of your head to your feet. Bracing your core and engaging your glutes, quads, and arms, rock your body forward a couple of inches so your shoulders go past your elbows and then rock your body back a couple of inches. Be sure to maintain a straight line with your body throughout the entire movement.

Pro tip: As you progress and get stronger, try this move in a high plank.

12. Mountain climber to downward facing dog split

How to do a mountain climber to downward facing dog split: Start in a high plank position with your shoulders directly over your wrists. Engaging your lower abs, drive your right knee toward your right elbow. Keeping your left foot rooted on the mat, lift your right leg behind you, extending your right foot toward the ceiling. Repeat on the other side. This is one rep.

13. Downward facing dog to alternating knee taps

How to do downward facing dog to alternating knee taps: Start in a high plank position with your shoulders directly over your wrists. As you push your butt back into a downward facing dog, lift your left hand off the mat and reach for your right knee, tapping it gently. Bring your left hand back to the mat and repeat on the opposite side. This is one rep.

14. Plank pikes

How to do a plank pike: Start in a high plank position with your shoulders directly over your hands and toes on top of a pair of gliders or hand towels. Engaging your core, slide your feet toward your hands, keeping your legs as straight as you can. Your butt will pike up toward the ceiling. Pause for moment and then slide your feet back out to a plank. This is one rep.

15. Mountain climbers with gliders

16. Froggers with gliders

17. Plank toe taps