Does your form need fixing? Exercise has the ability to transform your figure, improve athletic ability, and even prevent disease and illness. However, for fitness to be effective and safe, it must be performed properly.

One of the most common types of exercise that fall to faulty form are core workouts. Here are the top three fitness fails to avoid during your next gut-busting routine:

Planks. Don't underestimate the difficulty level of this static exercise. After a few seconds, you will quickly learn how much energy it takes to pull the plank off perfectly. The No. 1 pitfall in this position is lifting your butt too high in the air. Instead, focus your efforts on keeping your back flat. If you are new to this move, master your form first, then slowly add more time as you progress.

Step 1. Begin in a prone position and prop your body up by resting on your forearms and toes.
Step 2. Push through your forearms and toes to elevate your body.
Step 3. Keep your shoulders aligned above your elbows and your body completely straight from your head through your heels. Squeeze your butt and engage your core for 30 to 60 seconds, depending on your strength level.

Sit-ups. This prehistoric exercise can be a real pain in the neck — literally. Most exercisers miss the midsection mark by pulling on their head and neck muscles rather than recruiting their core muscles to elevate the upper body. This often results in a sore neck and underworked abs. It's for this reason that planks should always take priority over sit-ups. But if you aren't ready to kick sit-ups to the curb, here is the safest way to perform them.

Step 1. Start in a supine position, keeping your knees bent and feet firmly planted on the floor. Your legs should be positioned hip-width apart.
Step 2. Elevate your arms so your fingertips are lightly touching the outside of your ears. Avoid clasping your hands behind your head to prevent pulling on your neck.
Step 3. Engage your core muscles and slowly lift your upper body off the floor. Hold for two breaths then return to the starting stance.

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Mountain Climbers. This high-intensity, compound exercise simulates a stationary hike. Mountain climbers enhance your glutes, legs, and abs in addition to increasing caloric expenditure and muscle stability. But, much like the plank, an elevated backside can render this exercise useless.

Step 1. Begin in a push-up position with your shoulders stacked over your hands and your back flat. Keep your core muscles tight throughout the duration of this exercise.
Step 2. Drive your right knee up toward your chest, return it to the starting position, then quickly repeat with your left knee. Avoid dropping or lifting your hips or pushing too far forward on your arms.
Step 3. Continue rapidly alternating legs for at least 30 seconds.  Increase the duration of this exercise for an added challenge.

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Keep your tummy toned and tight by fixing faulty form.

Ashley B. Greenblatt is a certified personal trainer and wellness coach. To learn more, visit ashleyblakefitness.com.