No, not sit-ups — trainer shares these 6 exercises to blast your core in just 12 minutes

woman doing a crunch
(Image credit: Shutterstock)

Whether you outright loathe doing a sit-up or you are simply looked to freshen up your ab workouts in 2025, here is a six move workout that doesn't involve any sit-ups and only takes 12 minutes to complete.

The routine comes from fitness trainer Sandy Klar who has focused on using bodyweight moves only, which means you can do this workout anywhere. You can use it as an ab finisher at the gym, or as a standalone routine at home on one of the best yoga mats, or you could even do it in the park after a run.

Sklar shared the workout on her Instagram where she provides demonstrations of each exercise, but you can also view these below. According to Sklar, you will complete all six exercises in a circuit, performing each for 30 seconds with little to no rest in between, and repeat four times.

Watch Sandy Sklar's 12-Minute Core Building Workout

  • Low plank with alternating extended arm reach/press
  • 3 point dolphin plank
  • Commando plank (plank up)
  • Reverse crunch with extended leg hip raise
  • Alternating leg raise with crossbody reach
  • Bicycle crunch with 3-count pause

I hope you like planks because the first three moves of the workout involve planks. But don't worry, they aren't like the standard plank where you get on your elbows and set a 60-second time of doom on your phone.

They are much more versatile, adding in arm extensions and different maneuvers that keep your focus on what you are doing and not how long you are holding a position. Plus, you only need to work for 30 seconds before taking a breather and moving on to the next exercise. These different plank variations will engage and challenge your core muscles but they'll also target some of your upper body muscles including your shoulders and triceps.

Next up are two different styles of crunches and some leg raises. Throughout this final half of the routine, you will be using your lower abs, obliques and hip flexors. The hip flexors are a group of muscles that allow you to move and flex your legs and are important to work because they contribute to various things like your core stability, mobility, and aid functional movements like walking, running, and squatting.

The terms abs and core are often used interchangeably but there is a difference between the two. Your abs refer specifically to the muscles in the front of your abdomen (the 'six-pack' muscles), while your core includes not just your abs, but also the muscles in your lower back, hips, and pelvis. Want to know more about this? Read a personal trainer's take on abs vs core muscles and why you should know the difference.

It’s a good idea to build regular core and ab workouts, like this one from Sklar, in your weekly exercise regime to improve overall strength, stability, and posture. A stronger core can also help prevent injury by providing better support for your spine, improving your posture, and enhancing your balance, which reduces the risk of strains and falls during physical activities.

Additionally, consistent ab exercises can lead to a more toned appearance. Juts remember that results will vary depending on factors like genetics, diet, and overall body fat percentage.

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Jessica Downey
Fitness Writer

Jessica has been a fitness writer at Tom’s Guide since 2023, bringing three years of experience writing about health, fitness, and the great outdoors. Her passion for exercise began during her childhood, where she spent weekends hiking and competing in local athletics club events. After earning a master’s degree in journalism from Cardiff University, Jessica found the perfect way to combine her love of storytelling and fitness into a career.

Jessica is passionate about testing fitness gear and tech, using her reviews to help readers make informed buying decisions. She ran her first marathon in April 2024, finishing it in 3 hours and 48 minutes. Through her training, she’s developed a deep understanding of what it takes to grow as a runner, from effective workouts and recovery techniques to selecting the right gear for every challenge.

When she’s not at her desk, Jessica enjoys spending time in the kitchen crafting new recipes, braving cold water swims and hiking.