Background During antenatal period, many woman experience an increase of inter-rectus muscle distance (IRD) due to a weakening of the linea alba, considering a widening of >2 cm pathological. Hypopressive exercise is thought to be an important treatment modality to prevent or to treat the diastasis of the rectus abdominis muscles by the assumption that contraction of deep abdominal muscles will reduce the abdominal horizontal diameter, producing the approximation of both rectus abdominis muscles, particularly at umbilical level.

Ultrasound image may be considered the gold standard for clinical measurement of IRD with a low standard error of measurement (SEM) of 0.05 to 0.20 cm.

The aim of the present study is to compare the effect of a ten weeks supervised hypopressive exercise program on inter-rectus distance (IRD) in primiparous women.

Methods Eight postpartum primiparous women with vaginal delivery and a IRD of >2 cm participated in the study. Ultrasound images were collected above umbilical level(3 cm) during rest, at the end of exhalation and in supine position(knee bent 90°) with a Sonosite M-turbo portable ultrasound scanner(7,5 MHz,60 mm linear transducer), previous and post intervention.

All the participants completed a ten weeks supervised hypopresive exercise program, divided in one sesion each week.

Results Dependent variable (IRD) was analysed with a T-student test. Previously was found to satisfy Shapiro-Wilk´s normality test. A significant difference in IRD was observed between pre-intervention data {mean 24,3 mm [standard desviation (SD) 2,6] mm vs post-intervention [mean 21,5 (SD 2,4) mm. Mean difference was observed after intervention of 2,3 mm; 95% confidence interval (CI) (p<0,05).

Conclusions Following 10 weeks of hypopressive exercise, IRD decreased suggesting that this exercise modality can be incorporated into pospartum exercise programs when a increase of IRD is observed. Hypopressive exercise require minimal equipment and represent a great alternative to increase strength of the abdominal muscles of women postpartum. Further research is needed with larger simple size and comparing with a control group.