Curl-up exercises improve abdominal muscle strength without worsening inter-recti distance in women with diastasis recti abdominis postpartum: a randomised controlled trial

QUESTION: What is the effect of a 12-week, home-based, abdominal exercise program containing head lifts and abdominal curl-ups on inter-recti distance (IRD) in women with diastasis recti abdominis (DRA) 6 to 12 months postpartum? What is the effect of the program on: observed abdominal movement during a curl-up; global perceived change; rectus abdominis thickness; abdominal muscle strength and endurance; pelvic floor disorders; and low back, pelvic girdle and abdominal pain? DESIGN: This was a two-arm, parallel-group, randomised controlled trial with concealed allocation, assessor blinding and intention-to-treat analysis. PARTICIPANTS: Seventy primiparous or multiparous women 6 to 12 months postpartum, having a single or multiple pregnancy following any mode of delivery, with a diagnosis of DRA (IRD > 28 mm at rest or > 25 mm during a curl-up). INTERVENTION: The experimental group was prescribed a 12-week standardised exercise program including head lifts, abdominal curl-ups and twisted abdominal curl-ups 5 days a week. The control group received no intervention. OUTCOME MEASURES: The primary outcome measure was change in IRD measured with ultrasonography. Secondary outcomes were: observed abdominal movement during a curl-up; global perceived change; rectus abdominis thickness; abdominal muscle strength and endurance; pelvic floor disorders; and low back, pelvic girdle and abdominal pain. RESULTS: The exercise program did not improve or worsen IRD (eg, MD 1 mm at rest 2 cm above the umbilicus, 95% CI -1 to 4). The program improved rectus abdominis thickness (MD 0.7 mm, 95% CI 0.1 to 1.3) and strength (MD 9 Nm, 95% CI 3 to 16) at 10 deg; its effects on other secondary outcomes were trivial or unclear. CONCLUSION: An exercise program containing curl-ups for women with DRA did not worsen IRD or change the severity of pelvic floor disorders or low back, pelvic girdle or abdominal pain, but it did increase abdominal muscle strength and thickness. REGISTRATION: NCT04122924.