You don't need crunches to build core strength, just this one dumbbell ab exercise

Crunches and sit-ups are popular ab exercises designed to help strengthen the muscles around your mid-section. However, that doesn't mean they're the most effective. Instead, try switching crunches for this personal trainer's favorite core exercise, dumbbell dead bugs.

You only need a single dumbbell to get started, although it's worth investing in a set of the best adjustable dumbbells if you regularly exercise at home. These customizable weights are a space-saving option as they combine several dumbbells in one.

This core-strengthening advice comes from personal trainer Alice Liveing, who recently posted on Instagram about the differences between ab exercises and core workouts, even though they seem pretty similar initially.

Rather than spend hours on crunches and sit-ups, Liveing suggests that you switch these classic ab exercises for a weighted dead bug instead. The bodyweight version is a workout staple, but there's a good reason to add a dumbbell into the mix.

As Liveing explained, "this is one of my favorite core exercises. An advancement on a typical dead bug, this core exercise works anti-extension, focusing on training the core to [resist] the extension through the spine."

Watch Alice Liveing's dumbbell core exercise

The main focus of this weighted dead bug is on developing core strength. Your core is an area of mid-body muscle, including your rectus abdominis (the six-pack ab muscle). There are several practical reasons to prioritize core strengthening exercises in your workouts. 

Developing a stronger core helps improve your stability and balance, promotes circulation, and aids your performance in other exercises. Your abs play a role in this process, but moves like crunches and sit-ups don't really help if your goal is visible abs. 

Liveing noted that "abs aren't made through endless ab exercises. Our abdominal muscles simply appear more the lower our body fat across our abdomen, so reducing body fat = abs. Not doing 100 sit-ups before bed."

If you're just starting out and want to get the most from your training, Liveing shared her top beginner strength training tips, including choosing the right weight, the differences between sets and reps, and the most effective styles of muscle-building workout.

One of the most time-efficient ways to train is to use multi-muscle compound moves like kettlebell swings. Helpfully, you only need one of the best kettlebells to develop strength, improve your metabolism, and burn fat with this high-intensity exercise.