Ditch sit-ups — strengthen and define your core with 1 dumbbell and this 5-move ab workout

woman doing side plank exercise
(Image credit: Shutterstock)

I don't have any real issue with sit-ups, but my tailbone isn't a fan. The good news is you don’t need to do sit-ups to build a strong core. If you're like me and can take or leave sit-ups, there are plenty of great core-strengthening exercises out there, and this routine from trainer James Stirling is one worth trying.

Stirling, also known as the London Fitness Guy on Instagram, regularly shares strength-building exercises that require minimal equipment and suit different fitness levels. This routine leans slightly more toward the intermediate side since it includes a dumbbell in some of the moves.

That said, beginners can still give it a go, just be mindful not to start with too heavy a weight. If you regularly train your core at home or plan to, investing in one of the best adjustable dumbbells can be a great space-saving and flexible weight option.

Watch James Stirling's 5-Move Core Building Workout

  • Drags x 40s
  • Twists x 40s
  • Side Plank x 20s
  • Jack Knife x 40s
  • Commando Plank x 40s
  • Complete 3-4 sets

Try to resist going too hard in the first round. You’ll want to preserve your stamina, as Stirling has designed this circuit to be repeated three to four times. Instead, direct your focus toward nailing good form, and that means making sure your core is engaged.

How do you engage your core? The best advice I’ve ever received came from a yoga teacher who told the class to imagine bracing your stomach as if you’re about to be hit. The good news is, the only hit coming your way here is an intense ab workout.

Since some moves in this routine are more challenging than others, you’ll spend varying amounts of time on each, though never more than 40 seconds. There are no built-in breaks, so if you start to struggle, allow yourself some short rests between rounds to help you push through to the final reps.

With all five exercises performed on the floor, this routine can be tough on your joints as you balance your body weight. That’s why I like to roll out one of the best yoga mats before starting as it keeps things comfortable and helps me perform at my best.

To ramp up the challenge, some of these moves incorporate a dumbbell, which not only increases difficulty but also helps build greater core strength and definition. That said, one workout won’t give you a set of washboard abs overnight.

As much as I wish it were that simple, I’ve been in the fitness game long enough to know that a few factors come into play. While consistency and patience are key, your overall body fat percentage also affects how visible your abs are. Since fat sits over muscle, a lower body fat level is necessary for muscle definition to show.

But, here is your friendly reminder that core training isn’t all about aesthetics. As with any workout we share, it’s about moving better, feeling stronger, and building a body that supports you in everything you do.

More from Tom's Guide

Jessica Downey
Senior 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.

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