You really want those six pack abs. Lately, though, whenever you go full bore and crunch to failure, you experience back pain during the workout, and it continues for hours or even days afterward. You might be concentrating too much on your abdominal muscles and not strengthening your back enough. Even so, crunches aren't the go-to ab exercise they used to be, specifically because of the back pain they can cause.
Cause of the Pain
Even though crunches are considered to be an abdominal exercise, they engage the hip flexors, too. Your hip flexor muscles are connected to the front of your lumbar spine so when you perform crunches, the hip flexors become tight and will pull your lumbar spine forward, causing pain. This effect is compounded if you spend your days sitting. That's because your hips remain in a flexed position most of the time, and then you hit the gym and intensify the tension already in your hips, resulting in more back pain.
Proper Crunch Form
Focusing on proper form when you're doing crunches helps encourage your rectus abdominus muscles to do most of the work and minimize the work your hip flexors do. Lie on a mat on the floor to reduce the pressure on your spine from the ground and bend your knees, placing your calves and feet on a bench or low table. Put your hands behind your neck, but only rest them there. Don't use them to pull your head up or forward. Raise your upper torso off the mat, keeping your lower back on the ground. Pause for a count of one at the top of the exercise and then lower your torso until your shoulders touch the mat, keeping your head and neck up off the floor. Repeat for 10 to 15 reps or until failure.
Crunches as effective ab exercises are often left out of an ab workout because their focus is just on ab muscles and not on strengthening the entire core. For a more well-rounded core routine that won't cause back pain, you should perform exercises such as front and side planks, glute bridges, two-arm cable presses and single-leg Romanian deadlifts. If you want to include a crunch in there somewhere, do a reverse crunch. This exercise is easier on your back because you lift your lower body, keeping your upper back flat on the bench.
Bring in the Ball
No matter what exercises you try, sometimes you just can't find a substitute that you're happy with. If you've worked on strengthening your back and core and want to bring crunches back into your routine, personal trainer Pete McCall recommends using a stability ball. McCall explains that the stability ball is shaped perfectly for providing support for your lower back and it won't put pressure on your vertebrae like the floor does when you do a traditional crunch. It also requires your hips and glutes to help support you, so it benefits more than just one muscle group.