The aims of this project are; 1) To examine the efficacy of ultrasound-guided pelvic floor muscle training compared to standard care on urinary incontinence in patients undergoing robot assisted radical prostatectomy and 2) To compare physical function, incontinence, and QoL in two groups of patients with low or high function of the pelvic floor muscles respectively before the surgery. This study consists of two parts. The first part is a randomized controlled trial where 44 patients with weak pelvic floor muscle function are randomized to either treatment as usual (control group 1) or ultrasound-guided pelvic floor muscle training (Intervention group). In the second part the patients in control group 1 will be compared with 22 patients with normal/strong pelvic floor muscle function (control group 2). Patients not able to perform the pelvic floor muscle test consisting of 8 repetitions of 4-seconds pelvic floor muscle contraction and 1 repetition of 15-seconds pelvic floor muscle contraction will be randomized to either intervention group or control group 1. Patients able to perform the pelvic floor muscle test will be included in control group 2.