Core training can be a controversial topic. The name itself evokes controversy and is shrouded in mystery with many trainers and clients. Let’s first discuss where your core is located. In the front of the body the core starts at the sternum and goes down to the front of your hips. In the back of the body the core starts below your shoulders and runs down to your gluteals. The purpose of your core is to keep your upper torso in extension (which means keeping your spine straight) while your upper and lower extremities can move.
Are sit-ups or crunches an effective way to strengthen my core? The answer is no because those two exercises place severe tension on the lumbar spine. The lumbar spine wants stability not mobility. The purpose of your core is to keep your spine straight not to round the spine. There have been a ton of studies about bridges and planks being safer than abdominal crunches (see Stuart McGill’s work)- but a lot of trainees are still doing crunches as they feel the benefit is worth the risk.
Two Studies:
1.) *Youdas et al. An electromyographic analysis of the Ab-Slide exercise, abdominal crunch, supine double leg thrust, and side bridge in healthy young adults: implications for rehabilitation professional.
JSCR. 2008 Nov;22(6):1939-46
CONCLUSIONS: The Ab-slide elicited the greatest EMG activity for the abdominal muscles and the least for the rectus femoris.
2.) Escamilla et al. An electromyographic analysis of commercial and common abdominal exercises: implications for rehabilitation and training.
JOSPT 2006 Feb;36(2):45-47
Compared infomercial “Ab training” devices and compared them to crunches and sit-ups
CONCLUSIONS: The Ab Slide and Torso Track were the most effective exercises in activating abdominal and upper body extremity muscles while minimizing low back and rectus femoris (hip flexion) activity.
Now both of these studies looked at infomercial devices which immediately turn most of us off—but don’t let that mislead you—both of those exercises (ab slide and torso tracker) are essentially abdominal roll-outs or planks- no flexion of the spine- all activation is due to stabilization. You don’t need an infomercial product to reproduce movement.
In other words- an abdominal roll out may actually be MORE EFFECTIVE at activating the recutus abdominus than crunches or sit-ups. So not only are the planks/roll outs a SAFER option, they could actually be a SUPERIOR choice.
About the author: Justin Lund is a personal trainer at WRRFC who specializes in Corrective Exercise Strategies to help improve the quality of his client’s movements.