Let's face it. Crunches aren't exactly one of the most exciting ways to trim your midsection into shape - but they are one of the most effective. After a while, pushing through the same old set of routine crunches with your waist-trimmer belt strapped around your middle simply doesn't cut it anymore, and that's when you need to start trying out variations that challenge your body and work your muscles in brand new ways.

The following simple crunch variations are a great way to add a touch of extra spice to your boring workout routine, so that you can get the benefits of sit-ups, without sticking to the same tired moves.

1.    Wide-Leg Crunch

You're going to need flexible hips to make these simple crunch variations to work for you, but even if you struggle a little bit to begin with, you should still start to see the benefits early on, and you can always work on your flexibility over time. Start by sitting in a butterfly position, with your arms over your head, and the soles of your feet together, so that your knees splay out to either side. Reach forward to touch the tips of your toes with your fingertips, using the strength of your abs to pull your weight.

2.    Running Man Crunch

This fun approach to simple crunch variations allows you to channel your inner MC Hammer. Similar to the standard bicycle crunch, you start by lying flat on the floor with your hands behind your head. As you curl upwards, exhale, and twist your torso while bending your right knee, so that you touch your right knee with your left elbow. Make sure you drop all the way back to the starting position before you repeat on the other side.

3.    Reverse Crunch Pulse

If you're struggling to find simple crunch variations that properly work your lower abs, this could be the perfect solution. Start by lying flat on your back with your legs up in the air, feet parallel to the ceiling. Keep your arms stretched out by your sides, palms facing down, and squeeze your lower abs to raise your lower back and butt away from the floor in quick pulses. Try to focus on using your abs as much as possible for this movement.

4.    Stability Ball Back Crunch

You'll usually find that when it comes to simple crunch variations, investing in a stability ball is a good idea. This particular movement makes use of the ball as a way of balancing out your abdominal work by putting some of the focus on your back. Start with your feet on the floor and your hips and stomach against the stability ball. Hold your hands behind your head, and use the muscles in your lower back to raise your body up and away from the ball, before slowly lowering back into the starting position.

5.    Scissor-Kick Crunch

Finally, this variation may make you look like a toddler having a tantrum, but it's a great way to get your lower abs burning. Lie on your back with your hands beneath your tailbone. Keeping your back flat, raise one leg as high as you can while keeping it straight, then as that leg lowers, raise the other one. Keep going for as long as you can. -*