Throw out those boring, stale crunches and mix up your ab routine with some of our experts’ favorite stomach tightening moves. Create your own routine by picking and choosing from the moves below, shooting for a 10 to 15-minute long session. Pair this with healthy eating, and all you need to see a real difference in your waistline are two to three sessions per week (on non-consecutive days). Vary it up: choose different moves each time you do your ab workout to keep things interesting and to continue challenging your core’s different muscles!

The Plank

Begin by lying flat on your stomach on a mat. Get into position by placing your forearms on the mat and lifting up so that your shoulders are right over your elbows. Extend your legs out behind you and balance your weight on the backs of your forearms and the tips of your toes. Be sure to not arch your back or lift your hips too high from the mat—your body should maintain a straight line from your shoulders to your feet.

Certified personal trainer Kimberly Garrison recommends beginning by holding the position for at least 10 seconds and work your way up to 60 to 90 seconds. Repeat for three sets.

Side Plank

On a mat, begin on your right side with your legs straight and stacked one on top of the other. Extend your right arm so that you are supporting yourself on your right elbow, which is aligned under your shoulder. Putting your left hand on your left hip, keep your body straight with your hips elevated off the ground.

Garrison recommends beginning by holding the position for at least 10 seconds and work your way up to 60 to 90 seconds. Switch to left side and repeat. Repeat for three sets on each side.

Leg Raises

Begin on your back, with hands flat under your butt (for extra support) or to either side of your hips, extending both legs toward the ceiling with your feet flexed. Slowly lower both flexed legs to the floor until they are about six inches from touching the floor. Be sure to really engage your core as you lower your legs. Raise both legs back to starting position. Garrison recommends repeating for three sets of 10 to 25 reps.

Seated Russian Twist

Begin by sitting on the ground with your legs straight in front of you. Lean back slightly—be sure to keep your back straight (don’t round your spine). Extend your arms straight out in front of you with your hands side-by-side and bend your knees so that your feet touch the mat. Tightening your core, slowly twist out to one side, then slowly twist back to the center. Inhale at the center point and then repeat on the other side. That’s one rep. Repeat three sets of 12 reps. To increase intensity, you can hold a medicine ball or a weight in your hands (as pictured).

Vertical Scissors

Begin on your back and extend your arms so they’re against your body with your palms flat on the mat. Lift both legs up about a foot off of the floor, concentrating on tightening your abs so your lower back is flat against the mat. Lower one leg down to the ground until it is a few inches from touching. Slowly raise this leg back up to the ceiling, while lowering the other leg toward the mat, creating a scissor motion. That’s one rep. Do three sets of 8-12 reps each.

Horizontal Scissors

Similar to the vertical scissors except this move goes side to side instead of up and down. Begin in the same starting position as the vertical scissors, raise both legs about six inches off the floor. Spread your legs apart, then bring them back together again, crossing your right foot over your left. Open your legs again, and when you return them back together, cross your left foot over your right. That’s one rep. Do three sets of 8-12 reps each.

The Roll-Up

Begin on your back with knees bent and your feet flat on the floor. Keep your shoulders flat on the ground and hold the backs of your thighs. Curling your chin to your chest, lift your shoulders off of the mat, reach your hands forward and try to touch your toes as you continually roll up and straighten your legs forward. Bend your knees back to the bent position and roll your back down slowly to beginning position. Repeat five times.

Double Ballerina Leg Lift

Beginning sitting on your mat, extend your legs keeping your thighs together and toes pointed. Lean back with your forearms on the mat and palm flat with fingers forward. Raise one arm overhead while leaving the other on the mat. Use your abs to twist your torso to the left while lifting both legs 45-degrees in the air. Return to forward center, lower your legs and repeat on opposite side. This is one rep. Do 10 reps for three sets.

The Hundred

Lay on your back with your toes pointed and knees bent at a 90-degree angle (shins parallel to the floor). Straighten your arms at your sides with your palms flat on the floor. Curl your chin to your chest and lift your shoulders and head off the floor while tightening your core to keep your lower back against the ground. Raise your arms off the mat and above your hips. Keeping them straight, hold the position and pump your arms up and down for 10 seconds. Return to beginning position and repeat for 10 reps.

The Toe Dip

Starting on your back with your knees bent at a 90-degree angle and shins parallel to the floor, straighten your arms at your sides with your palms down. Hold one leg in this position and slowly lower the other foot toward the mat (keeping the leg being lowered bent at a 90 degree angle). Lower your foot as close to the ground as possible (without touching it), then slowly raise your leg back up to the starting position and repeat on the opposite leg. This completes one rep. Repeat for five reps.

Side Imprint

Standing with your feet shoulders width apart, left hand on your left hip, raise your right arm above your head. Shifting your weight onto your left leg, rotate out your right leg at the hip so that your toes are turned outward. Raise your right knee up as you crunch your right elbow down to meet it. Make sure you’re squeezing your waist and isolating your obliques as you perform this motion. Then slowly return to starting position. Do 10 on one side, then 10 on the other. Repeat three times.