Using the same Vishee neuro-muscle stimulator as the sEMG assessment with a vaginal probe was inserted into the vagina and placed close to the PFMs. Three standardized programs were used in our study: (1) Tens electricity (first program): 5 min of 50-280 Hz frequency and a pulse duration of 50 µs. (b) Endorphin electricity (second program): 5 min of 1-10 Hz frequency and a pulse duration of 200 µs. (c) Spasmolysis electricity (third program): 5 min of 1-2 Hz frequency and a pulse duration of 300 µs. At the same time, patients could learn about their neuromuscular activity through the biofeedback instrument, abdominal breathing for 5 sec was necessary when PFMs were overactive.

1. A standardized and structured vaginal examination was performed by digital palpation to identify pelvic floor active MTrPs, and then pain mapping was developed for the patient's use.
2. Patients were required to participate in intensive training regarding myofascial release techniques. (I) Pressing: press directly on a specific MTrP with gentle, slow pressures (2kg/cm2) using a flat palpation, the pressure was sustained until the participant perceived the pain decreased and taut band released, and then gradually increased to previous level of MTrPs tension and maintained until a reduction of pain again. The process was usually 3 to 5 repetitions for 90 sec. (II) Stretching: stretch in parallel to the direction of the myofascial to facilitate elongation of a contracted muscle. (III) Strumming: stroking and strumming the affected muscles region with the fingertips to aid in MTrPs tension release, the initial pressure was small and increased gradually until the patients adapted.

For the BES intervention, it was performed using the same Vishee neuro-muscle stimulator as the sEMG assessment with a vaginal probe was inserted into the vagina and placed close to the PFMs. At the same time, patients could learn about their neuromuscular activity through the biofeedback instrument, abdominal breathing for 5 sec was necessary when PFMs were overactive. BES was performed once every 2 days for 4 weeks.

Pain intensity was calculated by using the visual numeric rating scale (NRS), which is a 11-point rating scale ranging from "0" (no pain) to "10" (worst pain imaginable) . For each patient, the NRS referred to pain elicited while palpating bilaterally each PFM groups and was averaged pain across all the muscles. Upon palpation, the patient was asked to place in a resting, semi-recumbent position with legs supported by pillow to prevent excessive tension in the PFMs.

MTrPs were considered as active when the following criteria was met: (1) Presence of a palpable taut band in the muscle; (2) Presence of a hypersensitive spot in the taut band; (3) Local twitch response elicited by snapping palpation; (4) Reproduction of the typical referred pain pattern in response to the compression of tender spots; and (5) Spontaneous presence of the typical referred pain pattern. Active MTrPs localized mainly in the bilateral obturator internus, levator ani, piriformis and coccygeus were assessed respectively by pelvic floor manual palpation. Using the inclusion criterion of having active MTrPs at least one in the bilateral muscles as a cutoff point.