The Issue: Weak Transverse Abdominals
When your innermost abdominal muscles aren't firing properly and tightly holding in your trunk's organs and bones, you tend to get a potbelly effect – see, it's not always caused by beer – and can experience unnecessary back pain when doing crunches, says Reavy. This one is fairly easy to spot, but in case you're unsure, get in plank position in front of a mirror. If you don't consciously hold your breath, does your belly hang down? Does your back hurt?
Because the transversus abdominis muscles connect to your hips, sometimes the reason they're not activating is simply because your hip flexors are tight, says Reavy. To prevent that from happening, stretch out your hips (see move #2 for tight hips), and then do a series of plank holds and side planks to help strengthen the inner abs. Do 3 sets of 15 reps of plank, right side plank, and left side plank, at least three days per week.