This three-minute core series from Barry's Bootcamp [1] trainer Allie Cohen is just what you need to amp up your workout for bikini season. Allie loves tacking this ab-burning circuit to the end of her intense calorie-torching workouts (check out her 25-minute no-equipment workout here [2]) in order to work the core even harder. The result? You'll be ready for any Spring break vacation plans in no time.

Here's a list of the six moves, each performed for 30 seconds with a 30-second rest at the end. Try repeating the entire circuit up to three times, resting for 30 seconds between each circuit, for a 10-minute core workout. Even if you only repeat once, this series works well as an add-on to a total-body workout — or even just a quick way to tone abs while you're watching TV or starting your day.

• Basic crunch
• Tabletop crunch
• Tabletop crunch with hold
• Bicycle crunch with hold
• Side crunch, left side
• Side crunch, right side

Basic Crunch

Reps: 30 seconds

• Lie on your back with your knees bent and feet about 12 inches from your butt. Put your hands behind your ears or cross arms over your chest.
• Focusing on your core muscles, lift your head and shoulders and raise up until your head, shoulders, and back are off the floor. Keep your belly button pulled in.
• Lower back down to complete one rep. Repeat for 30 seconds.

Tabletop Crunch and Tabletop With Hold

Reps: 30 seconds of crunches, then 30 seconds with hold.

• Lie on your back with a neutral spine. Lift legs up and bend knees so they are at a 90-degree angle. Place hands behind your head or crossed in front of your chest (not shown).
• Lift your head, shoulders, and back so they are off the ground, focusing on pulling from your core. Try to touch your elbows to your knees.
• Lower to complete one rep. Repeat for 30 seconds.
• After 30 seconds, perform three tabletop crunches as before, but hold at the top with elbows to knees for three seconds at the last crunch. Lower down, then repeat this three crunches, three-second hold sequence for 30 seconds.

Bicycle Crunch With Hold

Reps: 30 seconds

• Lie flat on the floor with your lower back pressed to the ground (pull your abs down to also target your deep abs). Interlace your fingers, and put your hands behind your head.
• Bring your knees in toward your chest, and lift your shoulder blades off the ground.
• Straighten your right leg out to about a 45-degree angle to the ground while turning your upper body to the left, bringing your right elbow toward the left knee. Make sure your rib cage is moving and not just your elbows.
• Now switch sides and do the same motion on the other side to complete one rep (and to create the "pedaling" motion).
• Continue this quick pedaling motion for 30 seconds, pausing for two counts every third rotation (eg, right foot out, left foot out, then hold right foot out and touch left elbow to right knee. Then left foot out, right foot out, then hold left foot out and touch right elbow to left knee).

Side-Plank Crunch

Reps: 30 seconds, each side

• Begin in a side elbow plank with your left elbow down and your right hand behind your head.
• Keeping your torso stable and your waist lifted, bring your right leg up toward your shoulder to lightly tap your right elbow.
• Lengthen your right leg back to the starting position to complete one rep.
• Repeat for 30 seconds, then flip so your right elbow is on your mat and repeat on your left side for 30 seconds.