The postural response of the pelvic floor muscles during limb movements: a methodological electromyography study in parous women without lumbopelvic pain.

BACKGROUND: Pregnancy-related lumbopelvic pain is common. More than 30% of women have persistent pain 3 months after giving birth. There is no consensus regarding the pathology. However, coordination of muscle activity by appropriate timing and amplitude is necessary for maintaining adequate stability in the lumbopelvic area. The aim was to develop a method using surface electromyography to detect a feed-forward response in the pelvic floor muscles during limb movements performed at a comfortable speed applicable in future studies for women with lumbopelvic pain.

METHODS: Ten parous women with no lumbopelvic pain in the past 12 months were included. Surface electromyographic activity was recorded from the pelvic floor muscles and unilaterally from transversus abdominis/internal oblique, rectus abdominis, erector spinae, hip adductors, rectus femoris and deltoid. The subjects performed leg lift in supine and arm lift from standing. The electromyographic onset was related to the initiation of the movement.

FINDINGS: In the majority of the women the electromyographic onsets of the pelvic floor muscles occurred before the movement was initiated, regardless of whether it was a leg or an arm lift. In addition, electromyographic onsets for the other muscles, except the rectus abdominis during the arm lift, also occurred prior to the movements.

INTERPRETATION: The findings suggest a feed-forward response in the pelvic floor muscles during leg and arm lifts in women who had previously given birth and were without lumbopelvic pain. Movements performed at a comfortable speed seem to be useful in order to detect such a response.