The Impact of Breathing Training on PPSUI: A Randomized Controlled Trial

Pelvic floor muscle strength was assessed using the Modified Oxford Scale (MOS), a grading system originally developed by medical researchers at the University of Oxford to differentiate between varying levels of muscle strength. In this study, the MOS was employed to evaluate changes in pelvic floor muscle strength before and after treatment, and to guide decisions regarding the application of resistance during therapy. The standardized assessment procedure required patients to empty their bladder and assume the lithotomy position while relaxing their abdominal, gluteal, and thigh muscles. Following proper perineal disinfection and while wearing sterile gloves, the therapist inserted the index and middle fingers 4-6 cm into the vagina to palpate at the 5 and 7 o'clock positions. Patients were then instructed to perform maximal voluntary contractions of their pelvic floor muscles, with the therapist evaluating the muscle activity according to MOS criteria. All assessment data were sys

Pelvic floor muscle electrical activity was evaluated using the Glazer Protocol for Pelvic Floor Surface Electromyography. A vaginal electrode was inserted to collect sEMG signals while participants performed guided contraction and relaxation exercises. Participants maintained a 120-degree angle between their upper body and lower limbs, with legs extended naturally, feet externally rotated, and full-body relaxation to minimize engagement of abdominal, gluteal, and thigh adductor muscles.

The contraction rate of the TrA muscle was evaluated using the SonoScape S30 ultrasound imaging system in B-mode.

Contraction Rate = (Contracted Thickness) / (Resting Thickness)

The MVC was assessed by an experienced pelvic floor rehabilitation therapist using the Glazer Protocol for Pelvic Floor Surface Electromyography. Developed by pelvic floor muscle expert Dr. Howard Glazer, this gold-standard evaluation employs surface electromyography (sEMG) technology to record the electrical activity of pelvic floor muscles. The assessment provides comprehensive data on muscle activation speed, variability, and amplitude, enabling evaluation of overall relaxation/contraction function and monitoring rehabilitation progress.

For this study, measurements were conducted using the Malod MLD B4Splus biofeedback stimulator, which precisely captures and analyzes sEMG signals during maximal voluntary contractions.

Assessment was performed using the SonoScape S30 ultrasound imaging system. A curvilinear transducer C353 (SonoScape, China) with 3.0-5.0 MHz frequency was employed in M-mode to evaluate diaphragmatic movement. The transducer was positioned between the right midclavicular and anterior axillary lines, oriented medially, superiorly, and posteriorly to visualize the posterior third of the right hemidiaphragm.

In M-mode imaging, the diaphragm appeared as a hyperechoic line moving freely during respiratory cycles. The upward excursion during inspiration was recorded, with the range of motion measured vertically from baseline to peak. Measurements were obtained during three conditions:

Resting state (normal breathing)、Deep inspiration、Coughing

PFM displacement was evaluated using the SonoScape S30 ultrasound imaging system. In B-mode, a C353 curvilinear transducer (SonoScape, China) operating at 3.5-4.7 MHz frequency was employed to assess bladder base displacement. The transducer was positioned transversely along the midline of the suprapubic region.

As the urethra, bladder neck, and bladder are anatomically related to the pelvic floor, any bladder base displacement directly reflects PFM activity. The assessment protocol included:

Resting state: A reference marker ("X") was placed at the position of maximum PFM displacement during contraction Functional tasks: Participants performed deep expiration and coughing maneuvers Image capture: Maximum displacement points during tasks were marked as subsequent "X" points PFM activity was quantified by measuring the distance (in centimeters) between the resting "X" point and each task-induced "X" point, representing bladder base displacement.