Ab separation, also known as diastasis recti, is a common condition that affects many women after pregnancy. It occurs when the fascia between the two rectus abdominis muscles stretches and thins, creating a gap that can lead to a protruding belly and weakened core muscles. While ab separation is a natural part of pregnancy, it can also be a source of discontent for many women.
There are many exercises that claim to help heal ab separation, but one of the most controversial is the crunch.
Traditionally one concern is the effect that crunches can have on intra-abdominal pressure (IAP). IAP is the pressure inside the abdomen. When IAP increases, it can put stress on the abdominal muscles or downwards on the pelvic floor.
Research has shown that certain exercises, including crunches, can increase IAP. A study published in the International Journal of Sports Physical Therapy compared the IAP generated during a sit-up, a crunch, and standing up from a seated position. The study found that the sit-up and standing up produced higher IAP values than the crunch. The researchers concluded that the IAP generated during a crunch was within a safe range.
A recent study by Saleem et al. (2021) found that when it comes to improving ab separation in postpartum women, crunches may be more effective than other exercises. In the study, 62 postpartum women with mild to moderate ab separation were randomly assigned to either a crunch exercise group, a double leg lower exercise group, or a control group. The women in the exercise groups performed their assigned exercise for eight weeks.
At the end of the study, the researchers found that both the crunch and double leg lower groups had a significant improvement in ab separation compared to the control group. However, the crunch group had a greater improvement in ab separation than the double leg lower group.
So while there are concerns about the effect of crunches on IAP, the study by Saleem et al. suggests that crunches may be more effective than other exercises for improving ab separation in postpartum women.