We've picked four of our favorite abs and obliques exercises and rolled them into one fast and effective core workout.

In this video, we use the timing format typically seen in high intensity interval training (HIIT) workouts — 20 seconds on, 10 off, four times through for each exercise. It makes the routine fly by and the short bursts of activity followed by a quick rest period ensures that you're able to push yourself hard and give each of the 20 second intervals your best effort.

If at any point you start to feel too tired or your form starts to suffer, you can always take a very quick break before you jump right back in. On the other hand, you can make this routine much more difficult by adding weights. You can always do this workout 2-3 times through to really burn out your abs and bump up the calorie burn value as well.

Try it out and let us know what you think. We'd love to hear from you.

Workout Structure
4 Exercises
20 Seconds on, 10 seconds rest, 4x through for each exercise
No equipment
Warm up and cool down not included

Best Abs & Obliques Exercises
1) Jackknife Crunches - This seemingly simple move engages the entire abdominal panel, as well as the hip flexors and thighs.

2) Plank Steps - Planks are one of the best ways to target your entire core (abs, lower back) - in this variation, we step up the challenge by adding in "steps" while you're holding the plank, meaning that the core has to work even harder to stabilize, plus your lower body has to pitch in to help.

3) Russian Twists - Try just a few reps of this simple exercise and you're going to feel it in your obliques - the muscles that run along the sides of your core. Make sure to keep your back flat, even as your muscles start to fatigue, and pay special attention to rotating as far as you can in each direction (your body will try to cheat by subtly switching so that only your arms and shoulders are doing the rotating).

4) Toe Touch Crunch Pulses - This one is all about abs; lie on your back and crunch upwards towards your toes and pulse at the highest part of the range of motion that you can without using momentum or swinging. Do your best to go through the entire interval without taking a break or letting your ab muscles relax.

Note: We consider these the 4 best core exercises for targeting the muscles in the midsection; these are not the best way to lose belly fat. The best and fastest ways to lose belly fat are total body strength training, a combination of different types of cardio (HIIT, endurance, low impact, etc) and a healthy diet.