This study analyzes the effects of hypopressive exercises on the abdominal thickness of healthy subjects and compares the performance between women and men. We conducted a transversal observational study in 98 subjects (63% women). The muscle thickness is analyzed in transversus abdominis, internal oblique, external oblique, and rectus abdominis with ultrasound imaging at rest and during the hypopressive exercise (HE) in supine and standing position. Comparisons between rest and hypopressive exercise are carried out in the two different positions and between women and men. In the supine position, there is a significant activation of the transversus abdominis and internal oblique during hypopressive exercise ( < 0.001), and it is similar in both sexes, the external oblique is only activated significantly by men ( < 0.001) and rectus abdominis had no significant activation ( > 0.05). Our results show that standing transversus abdominis and external oblique significantly increased their thickness during HE with higher effects in men. Internal oblique also increased significantly, but with higher effects in women, and rectus abdominis had no significant increase. Men had similar effects to women during HE, with an activation of the deepest abdominal muscles. The unequal anatomy and the position could explain the different results obtained between the sexes.