Methods: Fifty-seven healthy nulliparous and physically inactive women were randomized to Pilates exercise program (PEP) with or without PFMC. Forty-eight women concluded this study (24 participants for each group). Every women evaluated before and after the PEP, by a one physiotherapist and an urogynecologist (UG). Both professionals were not revealed to them. This physiotherapist measured their pelvic floor muscle strength by using both, a perineometer (Peritron) and vaginal palpation (Oxford Scale) . The UG, who performed 3D perineal ultrasound exams, collected their data and evaluated the results for pubovisceral muscle thickness and the levator hiatus (LA) area. Both professional were masked to the group allocation. The protocol for both groups consisted of 24 bi-weekly 1-h individual sessions of Pilates exercises, developed by another physiotherapist who is specialized in PFM rehabilitation and Pilates technique.