I ditched sit-ups for this 4-move dumbbell workout — here's what happened to my core

Training my abs is always tough, so I figured why not push it even further? I swapped out the usual sit-ups and Russian twists for a four-move dumbbell workout to really spice things up. I've been doing this routine for the past week, and I can confirm, it takes the burn to a whole new level.I’m a big fan of the fitness trainer behind this workout, Sandy Sklar, because her workouts feel realistic and accessible, whether I’m at the gym or at home.

Unlike the picture-perfect fitness influencers filming in pristine studios with matching workout sets, Sklar keeps it real.She shows up in her garden or living room, wearing whatever she’s comfortable in, and proves that you don’t need a fancy setup to be strong. Her awesome physique speaks for itself — she clearly puts in the work — but she makes fitness feel doable rather than intimidating, which is what led me to bring a pair of the best adjustable dumbbells into my training this week.



Watch Sandy Sklar's 4- move dumbbell workout for the coreA post shared by Sandy Sklar | Fitness Trainer (@sandysklarxfit)A photo posted by on If you haven't watched Sklar's demonstrations above, here’s what you need to know to try her dumbbell core blast. You'll complete all four exercises listed below in a circuit format, aiming to take no rests, but short breaks if needed. Sklar recommends doing two to four sets in total.

Renegade row x 20 totalHigh plank with alt. knee to elbow drive x 20 totalPull over crunch x 15Lying leg raise with hip raise x 15Sklar went heavy so I went heavyFirst things first: Just because Sklar uses heavy dumbbells in the videos doesn’t mean you have to do the same. This goes for any workout you try.

I’ve been sticking to my core training and felt ready for a challenge, so I decided to up the weights. But guess what? I ended up lowering the weight to get through the full circuit.Choosing a heavier weight can make an exercise feel more challenging, but if it compromises your form or prevents you from finishing the set, it’s not worth it.

It's easy to look impressive lifting heavy weights, but if your form suffers or you're risking injury, it's counterproductive. So, I adjusted the weight to make sure I was still challenging myself, but not so much that I couldn’t finish with proper form.It worked the core and upper bodyI knew this workout would be a pretty solid challenge for my core, and after a few rounds, the burn was undeniable.

Part of me wanted to quit, but I also craved that post-workout satisfaction.As I pushed through, I became more aware of how each move engaged different muscles. The renegade rows had my shoulders and back working hard to keep me stable, while the pull-over crunches activated my lats and chest along with my abs.

The high plank knee drive tested my arms, upper body endurance, and even had my hip flexors engaged as I pulled my knee into my chest.This wasn’t just a core workout. It was a full upper-body challenge packed into four intense moves.

I wouldn't keep up with this everydayIf you're a regular reader of the fitness section of Tom's Guide, you’ll know we love a good challenge. Whether it’s walking with a weight vest for 5K every day or committing to a week of standing ab exercises, we like to put workouts to the test. The same went for Sklar’s routine, I had committed to doing it every day for a week.

By day four, I was feeling it. Laughing, bending down, and just getting into position for the workout had my abs reminding me of every rep. By the seventh day, my core wanted a day off, and I had tired myself out of doing the same moves day in and day out.

If there’s one thing this challenge reinforced, it’s that variety is key in any training routine. Your muscles need time to recover, and mixing things up keeps workouts feeling fresh and motivating. Sticking to the same routine every day might sound productive, but giving your body different challenges is just as important for progress and long-term consistency.

More from Tom's GuideI tried this 3-move shoulder workout — here’s what happened to my upper bodyPhysio says runners need these 3 calf strength variations in their training — here’s why I’m finally listeningDitch sit-ups — strengthen and define your core with 1 dumbbell and this 5-move ab workout.