Introduction

Many women are affected by diastasis recti abdominis (DRA) postpartum. This is a separation of the left and right rectus abdominis muscle along the linea alba. The prevalence of DRA is reported to be as high as 45% at 6 months and 30% at 12 months post-partum. The presence of DRA is associated with decreased abdominal muscle strength and pain. Many of these women are discouraged from performing abdominal crunches postpartum, but instead, they are prescribed pelvic floor muscle training and strengthening of the transversus abdominis. In 2020, the same author found that lifting the head when lying supine and doing abdominal crunches reduced the amount of abdominal diastasis. In this RCT, this was further investigated.

Methods

In this study, participants were randomly assigned to the intervention which consisted of abdominal strengthening, or the control group who received no intervention and who were discouraged from abdominal strengthening. Eligible participants were women who gave birth and were diagnosed with DRA 6 to 12 months postpartum. The diagnosis of DRA was based on the inter-recti distance, measured 2cm above or below the umbilicus. The cut-off was 2.8cm of separation between both sides of the rectus abdominis at rest or 2.5cm during an abdominal curl up.

The 12-week abdominal strengthening intervention consisted of a standardized exercise program which was done for 10 minutes per day for 5 days per week. The program only included 3 exercises: supine head lift, curl up (abdominal crunch), and oblique curl up. The details and progressions are displayed in the figure hereunder.

The primary outcome measure was the change in the inter-recti distance at the end of the 12-week training schedule. This was examined using transabdominal ultrasound by a trained physiotherapist.

Results

A total of 70 women with DRA were equally randomized to one of both groups. They were comparable at baseline except for the mode of delivery and their weekly physical activity minutes. The participants from the intervention group completed 74% of all prescribed exercise sessions. Two-thirds adhered to 80% or more of the prescribed exercise sessions.

All measurements of the inter-recti distance decreased (improved) over the 12-week period in both groups, with one exception in the control group when measured 2cm below the umbilicus at rest. There was, however, no significant difference between the intervention and control groups from baseline to week 12. Importantly, the DRA did not worsen throughout the intervention.

Questions and thoughts

This study found no benefit in performing abdominal strengthening postpartum for improving the inter-recti distance in DRA. Both groups improved over the course of 12 weeks. As a secondary outcome, the global rating of change was evaluated and 61% and 43% of the participants from the intervention and control groups respectively reported improvement in DRA. None reported a worsening of the condition. The intervention group improved the thickness of the rectus abdominis, and strength more than the control group. However, it was noted that the confidence intervals spanned worthwhile and trivial effects. Endurance of the abdominal muscles was very poor in both groups and failed to improve throughout the study. This may indicate that the exercises were too low load, not sufficiently performed (adherence), not specific enough to increase muscular endurance, or that the ACSM curl-up test was too difficult for these women postpartum. Yet, the participants were women who gave birth in the previous 6 months or 1 year following delivery. It is striking that 76% of the participants were unable to perform one abdominal crunch in the ACSM test procedure. Of course, this might reflect the advice women get to avoid abdominal strengthening postpartum. As this study showed no harm, women should be encouraged to perform general and abdominal exercises following childbirth.

Talk nerdy to me

Something to bear in mind is the natural history of abdominal diastasis. As seen from the prevalence of DRA (45% at 6 months and 30% at 12 months post-partum), the reductions seen in both groups may reflect natural history. Furthermore, individuals who were 6 months postpartum and those who gave birth 1 year ago were included. Six months of difference is a large timespan and it isn’t specified how the groups were balanced at baseline.

Take home messages

A 10-minute exercise program designed for abdominal strengthening postpartum, performed 5 days per week, for 12 weeks was not sufficient to improve DRA in women who gave birth in the previous 6 to 12 months. The exercises did, however, not worsen DRA, which is commonly feared. The exercise program was insufficient to improve the DRA but showed a slight improvement in abdominal strength and muscle thickness. As such, women should be encouraged to perform abdominal exercises after delivery.

Reference

Gluppe, S. B., Ellström Engh, M., & Bø, K. (2023). Curl-up exercises improve abdominal muscle strength without worsening inter-recti distance in women with diastasis recti abdominis postpartum: A randomised controlled trial. Journal of Physiotherapy.