I did seated oblique crunches for a week — here’s what happened to my abs

a photo of a woman holding a resistance band in a chair
(Image credit: Getty Images)

Forget everything I’ve said before — I’m a complete convert to seated ab workouts. Seated ab workouts are low-impact workouts that can be done from a chair, targeting your abdominal and core muscles. Unlike ab workouts that involve lying on your back on an exercise mat, seated ab workouts are accessible to those who can’t get down on the floor, have limited space, or simply want a workout that they can do from their office chair during a meeting. 

I recently added this seated workout to my routine, and did seated crunches every day for a week, but next on my list was the seated oblique crunch. 

Your obliques are the muscles that run along the side of your torso. Your internal and external obliques work with your abdominal muscles to help stabilize and balance the core. They also protect your lower back from injury, and help you sit, run, and walk with better posture. Read on to find out how to do a seated oblique crunch, and what happened when I added them to my routine for a week. 

As a reminder, what works for me might not be right for you and your body. If you’re new to exercise, or returning to exercise following an injury or pregnancy, it’s a good idea to check with a medical professional or personal trainer before starting a new exercise routine. It’s never a good idea to work one particular muscle group every day — your muscles need time to recover, repair, and grow. When I’m not doing workout challenges for Tom’s Guide, I only work my abs once or twice a week. 

How to do a seated oblique crunch

To do a seated oblique crunch, you’ll need a comfortable, stable chair. We’d recommend using a chair that doesn’t have wheels, and one in which you can comfortably rest your feet flat on the floor.  

an illo of a man doing a seated oblique crunch

(Image credit: Getty Images)
  • Start by sitting on the edge of your chair, with your feet flat on the floor and your abs engaged. Keep your torso upright and your back straight.
  • Place your fingertips behind your head, with your elbows pointing out to the side of your body.
  • Lift your left leg off the floor, and at the same time, crunch your left elbow toward your knee — it doesn’t matter if they don’t touch.
  • Keep your abs engaged, and return to your starting position.
  • Repeat on the opposite side.
  • Keep switching sides for the duration of the move.

Alternatively, you can crunch across your body, leaning your torso back slightly, and crunching your elbow to your opposite knee. Try both variations to work out which feels best for your body.

As with all of the best ab exercises, it’s important that this move comes from your core, not your upper body. Ensure that you’re not pulling your torso down — the grip behind your head should be relaxed, and you should think about engaging your obliques as you crunch. Remember to move slowly and with control, this is not an exercise to rush through!

I did the seated oblique crunch every day for a week — here’s what happened 

Ready to hear what happened when I did the seated oblique crunch for a week? Read on. 

I didn’t feel this one in my obliques as much as other exercises

For a lot of the seated ab exercises I’ve tried lately, I’ve been shocked by how hard they’ve worked my mid-section. Unfortunately, this wasn’t the case with the seated oblique crunches. Compared to oblique crunches on a stability ball, a Russian twist, or a farmer’s walk, I really struggled to feel my obliques working hard with this move. That said, I also struggle to feel my obliques working during standing oblique crunches, as our writer Lucy experienced when she did 50 oblique crunches a day for a week

One way to make the exercise more challenging is adding a weight — by the end of the week, I’d strapped a set of the best ankle weights around my ankles to up the intensity of the exercise. Alternatively, you could hold one of the best adjustable dumbbells in your hand, and lower it down toward the floor, before crunching back to your starting position, without the leg lift. 

I’d keep these as part of a longer seated ab workout

While I didn’t feel particularly challenged by this exercise, there are still huge benefits to working on my oblique muscles, especially as a runner. Your obliques play an important role in supporting your lower back and improving your overall posture. When it comes to running, keeping your abs engaged and your torso upright enables better form and efficiency, and can also prevent you from getting injured. 

Despite being glad my week of seated oblique crunches is over, I’ll definitely be incorporating these into seated ab workouts in the future. Chair workouts can help you work your muscles without putting any additional strain on your joints, so are often recommended to those recovering from an injury, as well as seniors, or pregnant women who might need a bit of extra stability during their workouts.

I didn’t notice any change in my abs

Of course, a week isn’t long enough to visibly change your muscles, and I didn’t notice any difference in my mid-section after a week of seated oblique crunches. That said, if visible abs are your goal, you’ll need to focus on your overall body fat percentage, not endless crunches. Your cardio levels, diet, stress, sleep and hormones can all affect your body fat percentage — here’s how to calculate your body fat percentage, and why it matters. 

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Jane McGuire
Fitness editor

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.