Intermediate Abs and Core Workout

7 Exercises to Build Strong Abdominals Fast

If you're experienced at the gym but haven't yet gotten the definition in your abs that you wanted, there are ways to achieve this over a relatively short period of time. The aim of a structured program is to build the various muscle groups that comprise your abdominals in a way that is targeted, intense, and safe.

This abs and core workout involves a variety of exercises designed to strengthen the rectus abdominis, obliques, transverse abdominis, and erector​​ spinae.

Workout Guidelines

For this routine, you will need a mat and an exercise ball. You should also have a few weeks of exercise experience under your belt.

While this is a great overall workout for intermediate gym goers, you should only do this workout if you have participated in strength training for at least 4 to 8 weeks.

To achieve the optimal results, you would need to adhere to the three fundamentals of every practice:

  1. Always begin each workout with a five- to- 10-minute light cardio warmup.
  2. Once warmed up, perform two sets of each exercise with 16 repetitions. Rest for no longer than 20 to 30 seconds between sets.
  3. Perform this workout two to three times per week with a day of rest between workouts.

Exercise Ball Crunches

Exercise Ball Crunches
Gary Burchell

The use of the exercise ball helps strengthen the core muscles because you are continually adjusting your balance. To do this exercise:

  1. Lie with your middle back on the ball with your hands placed behind the head.
  2. As you exhale, contract your abs and lift your shoulders, crunching the abs toward the hips without rolling on the ball.
  3. Lower as you inhale and repeat for two sets of 16 reps.

Reverse Crunches

Reverse crunches

Kevin Dodge / Getty Images

The reverse crunch intensifies the workout by removing your legs from the equation.

While the exercise provides stability by placing your back flat on the floor, the added weight of your legs adds stress to the lower stomach muscles.

To do this exercise:

  1. Lie on your back with your knees lifted a 90-degree angle, calves parallel to the floor.
  2. As you exhale, contract your abs to lift the hips off the floor and hold the crunch for a second or two. Try not to swing the legs or use momentum to lift your hips.
  3. Lower your hips as you inhale and repeat for two sets of 16 reps.

Long Arm Crunch

Long Arm Crunch

Verywell / Ben Goldstein

A long arm crunch is another variation in which your arms are extended so that you are less able to use momentum to crunch your abs. To do this exercise:

  1. Lie on a mat and extend the arms straight over the head. Keep your elbows straight and place your hands or palms together. Do not clasp your fingers.
  2. As you exhale, contract the abs and lift the shoulder blades off the floor. Do not move your arms forward; keep them straight overhead. If you need support, you can place one of your hands behind your head.
  3. Lower as you inhale and repeat for two sets of 16 reps.

Bicycle Crunch

Bicycle crunch.

Hero Images / Getty Images

Bicycle crunches are high-intensity crunches that help build the obliques. To do this exercise:

  1. Lie on your back with knees lifted a 90-degree position, calves parallel to the floor. Place your hands behind or to the sides of your head.
  2. Lifting the shoulders, straighten the left leg while twisting the left elbow to the right knee.
  3. Now straighten the right leg while twisting the right elbow to the left knee.
  4. Without dropping the shoulders, continue back and forth for a total of 16 reps. The slower you do this exercise, the harder it becomes. Rest for 20 to 30 seconds and start again.    

The Plank

Core Yoga Poses

Tetra Images / Getty Images

The plank is a deceptively simple exercise that develops strength in the core, shoulders, arms, and gluteus muscles. By maintaining a taut, stable posture, your abs are forced into an active position.

Most people are unable to hold the plank for more than 30 seconds when first starting out.

To do this exercise:

  1. Place hands directly under your shoulders like you're about to do a push up. To make it easier, rest on your forearms with your elbows directly under your shoulders.
  2. Keep your entire body tight. Don't let your belly sag or butt stick in the air. You want a straight line from your head to your heels.
  3. Start by holding this position for 20 seconds. As you become more comfortable with this exercise, hold your plank for increasingly longer periods of time.

Knee Tucks on the Exercise Ball

Exercise ball starting position

Ana Abejon / Getty Images

The knee tuck requires lateral balance and builds strength not only in the abs but the arms and shoulders, as well. To do the exercise:

  1. Kneeling on all fours, place your right foot and then your left foot on top of the exercise ball, positioning it under the tops of your shins. Hold your arms straight as if you were about to do pushups.
  2. With control, smoothly bend your knees toward your chest, letting the ball roll toward your feet.
  3. Now straighten your legs back into the starting position. Try not to push back on the arm; keep all of the movement in the knees.
  4. Repeat for 16 reps over two sets.

Back Extensions

Locust Pose – Shalabasana
Ann Pizer

This exercise has minimal movement but delivers a maximal impact. It is often referred to as the locust pose in yoga and is known to build strength quickly and safely.

To do the exercise:

  1. Lie face down with hands your hands to your sides.
  2. Inhaling, simultaneously lift your upper body and legs off the ground a few inches. Hold for three to five seconds, keeping the legs straight. For an added challenge, do the exercise with your arms extended out in front of you.
  3. Lower as you exhale and repeat for two sets of 16 reps.
6 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. International Sports Sciences Association. Is your warm up routine sabotaging your training?.

  2. Escamilla RF, Lewis C, Bell D, et al. Core muscle activation during Swiss ball and traditional abdominal exercises. J Orthop Sports Phys Ther. 2010;40(5):265-76.  doi:10.2519/jospt.2010.3073

  3. American Council on Exercise. Reverse crunch.

  4. American Council on Exercise. Supine bicycle crunches.

  5. American Council on Exercise. Stability ball knee tucks.

  6. American Council on Exercise. 5 lower back bodyweight exercises to ward off low back pain.

By Paige Waehner, CPT
Paige Waehner is a certified personal trainer, author of the "Guide to Become a Personal Trainer," and co-author of "The Buzz on Exercise & Fitness."