by Gareth Sapstead
Master the Reverse Crunch
Yes, you can target the lower-ab area, but no, it doesn't spot-reduce fat. Here's how to do the best exercise for lower abs.
The Truth About the Lower Abs
People do the reverse crunch to target the lower abs or lower belly area. And I already know what you’re thinking: “But that’s an issue of body fat! Besides, you can’t train just part of the abdominals!”
You’re right… and also partially wrong.
Having a low level of body fat will, of course, allow you to see your abs (both upper and lower). But if you want them to stand out, remember that abs are grown with resistance. Hypertrophy your abs and they’ll be more visible, even if you aren’t completely shredded all the time.
And just like any muscle group, exercise selection matters when it comes to building them. Here’s what you need to know about the reverse crunch. (Make sure you watch the video above to see it in action.)
Does the Reverse Crunch Really Target Lower Abs?
No single exercise can truly isolate a certain area of the abdominals. Even if your goal is to isolate the entire rectus abdominis (six-pack), it’d still be impossible to do so without other muscles getting involved at the same time. Things like the external obliques, for instance, will help out.
That said, with the right exercises and techniques, it’s possible to emphasize the muscle fibers that make up the lower portion of your rectus abdominis.
The rectus abdominis extends the length of the abdomen and from the pubis to the lower three ribs and sternum. So to work the muscle fully, you need to be using exercises that pull your lower ribs and pubis closer together.
It’s the lower abs that are largely responsible for the action of pulling the pelvis upwards (posterior pelvic tilt), and that’s the exact motion you do during reverse crunches. Research shows that the highest lower-ab activation can be achieved in a posteriorly-tilted position at the pelvis (1, 2).
So of all “lower abs” exercises out there, the reverse crunch is arguably one of the best, particularly when done on an approximately 30-degree decline bench.
The Big Reverse Crunch Mistake
One thing you want to avoid is pulling your knees towards your chest. It’s more of a tucking-in motion. You want to do it with your knees lifting up toward the ceiling. If you reverse crunch by bringing your knees towards your chest, the resistance will come closer to the movement axis (lumbar/sacral base) and reduce the load through your abs.
By moving your knees towards the ceiling and trying to keep your thighs vertical at the top, you’ll keep the resistance further away from the movement axis (lumbar/sacral base) and maintain the load through your abs.
How to Reverse Crunch
The Set-Up
- Set a bench to a 30-degree decline. The greater the decline, the greater the difficulty.
- Position yourself on the bench so your legs are in the direction of the decline.
- Hold on to the bench overhead or any other grip your bench has available.
- If you know that’s going to be too easy, clench a medicine ball between your knees or use ankle weights for extra resistance.
Performance
- Holding firmly overhead so as not to slide down the bench, flex your hips and pull your knees in and up towards the ceiling.
- Your knees will remain at approximately the same angle throughout.
- Imagine pulling your pelvis towards your ribcage as much as possible, with your hips coming off the bench at the top.
- Squeeze your abs hard at the top before lowering down fully.
- Don’t let your feet touch the floor between reps, although a soft touch (not bounce) on the floor is acceptable.
References
References
- Sarti MA et al. Muscle activity in upper and lower rectus abdominus during abdominal exercises. Arch Phys Med Rehabil. 1996 Dec;77(12):1293-7. PubMed.
- Workman JC et al. Influence of pelvis position on the activation of abdominal and hip flexor muscles. J Strength Cond Res. 2008 Sep;22(5):1563-9. PubMed.
