Incontinent women have altered pelvic floor muscle contraction patterns.

Area of Science:

• Urogynecology
• Pelvic Floor Muscle Physiology

Background:

• Pelvic floor exercises are crucial for urinary continence, but the underlying muscle activation mechanisms require further elucidation.
• Investigating the precise sequence of superficial and deep pelvic floor muscle contractions is key to understanding their functional role.

Purpose of the Study:

• To compare the contraction sequence of superficial versus deep pelvic floor muscles in continent and incontinent women across six different positions.
• To elucidate the electromyographic (EMG) differences in muscle activation patterns between continent and incontinent individuals.

Main Methods:

• Surface electromyography (EMG) using perineal and intravaginal electrodes was employed to record muscle activity onset.
• The study included 32 continent and 50 incontinent women.
• Agreement between electrode types was assessed using kappa statistic and percent agreement; contraction onset differences were reported as median and IQR.

Main Results:

• Perineal and intravaginal EMG recordings demonstrated high agreement.
• Continent women consistently exhibited superficial muscle contraction preceding deep muscle contraction in all tested positions.
• Incontinent women displayed a reversed contraction sequence in 3 of 6 positions, with greater variability in timing between muscle layers.

Conclusions:

• Both intravaginal and perineal electrodes effectively record pelvic floor muscle contractions.
• A distinct and consistent contraction sequence is present in continent women, but absent in incontinent women, potentially explaining incontinence.
• Incorporating exercises that target differentiated muscle contraction sequences may enhance pelvic floor muscle exercise program efficacy.