If you're looking for a great HIIT core workout, you want to choose one that targets all parts of your core—not just your rectus abdominis, the muscles that run vertically along the front of your abdomen.
To do this, you should focus on exercises that work your core through movement and anti-movement, Alicia Jamison, C.P.T., trainer at Bodyspace Fitness in New York City, tells SELF. That's because to really challenge your core, your muscles have to go through a range of motion as well as resist motion, which helps build stabilizing strength. Examples of anti-movement include anti-extension (where your core has to fire to resist the hyperextending of your lower back) and anti-lateral flexion (where you resist bending at the side), whereas flexion, or bending, is an example of movement.
By using various movement and anti-movement patterns, you'll challenge your transverse abdominis (the deep muscles on the front and side of your abdomen) and your internal and external obliques (the sides of your abdomen), as well as your rectus abdominis. This gives your core a 360-degree workout that you'll feel everywhere.
And training these muscles is super important, both in everyday life and during your workouts. After all, the main function of your core is to protect your spine. That's what helps you stay aligned when you're walking, twisting or rotating, carrying or lifting things, and sitting down, says Jamison. A strong core also helps improve your fitness and training, as it allows for a bigger transfer of energy from your upper body to your lower body and vice versa.
When it comes to core training, though, it can be tough to know whether your core is actually engaged—meaning, the core muscles you want to be firing (and which should be firing) are the ones that are actually working, rather than other muscles, like ones in your back (which you don't want to take over).
One tip: If you're doing a move where you're lying on your back, like flutter kicks or reverse crunches, push your lower back into the floor to eliminate the space underneath, which ensures the transverse abdominis and the rectus abdominis are engaged. If you're not lying on the ground, connecting to your breath is the easiest way to engage your core. “When you inhale, your ribcage opens up, and when you exhale, you can close the ribcage, engage the diaphragm, and pull those central tendons down into the core,” says Jamison. Essentially, you're contracting the muscles in your core as you exhale.
In this HIIT core workout created by Jamison, you'll be utilizing smaller moves for a big burn. And because it's HIIT-based, be ready to work hard with max efforts interspersed between your rest intervals.
Like with any HIIT-based workout, a proper warm-up is key: You definitely don't want to get into intense moves cold. Jamison loves doing low lunge twists—she calls them the “world's greatest stretch”—to dynamically warm up your whole body. To do this, reach down toward your toes and walk your hands out to a high plank. From there, step through with your right foot and place it outside your right palm, so you feel a big stretch in your hip. Then open up your chest, taking your right hand off the ground and reaching it up toward the ceiling for big T-spine mobility. Then do the other side.
Ready to hit the mat? Here's what you'll need for this short and sweet HIIT core workout.
The WorkoutWhat you'll need: An exercise mat for extra cushioning.
The ExercisesFlutter kickForearm side plank crunchReverse crunchRussian twistDirectionsPerform each exercise for 40 seconds, resting for 20 seconds after each move. Complete three times total.Demoing the moves below is Amanda Wheeler, a certified strength and conditioning specialist and co-founder of Formation Strength.

Fitness / Workouts