Visual Analogue Scale will be used to identify self-reported levels of chronic pelvic pain, dysmenorrhea, dyspareunia, dyschezia and dysuria.. Scores range from 0 to 10. Higher scores represent increased pain intensity

The Pain Catastrophizing Scale (PCS) will be also used to assess catastrophic thinking related to pain. Scores of this 13-item scale range from 0 to 52. Higher scores represent higher catastrophic thoughts.

Images of the abdominal wall, lumbar multifidus and quadriceps will be obtained using an ultrasound device with a 12 megahertz linear probe and a depth of 5 cm. The thicknesses of the external and internal oblique, the transversus abdominal muscles and the lumbar multifidus, as well as the width of the lumbar multifidus will be assessed. Three measurements of both right and left muscles diameters will be recorded with a 2-minute interval between trials.

Lumbar multifidus assessment will be performed at, the fifth lumbar vertebra, marking its spinal process.

Muscle trunk flexor endurance test will be used to assess the endurance strength of abdominal muscles by isometric endurance of trunk flexors. Time (in seconds) is measured, and higher scores represent better performance.

Muscle trunk extensor endurance test will be used to assess the endurance strength of back extensor muscles by isometric endurance of trunk extensors.Time (in seconds) is measured, and higher scores represent better performance.

Original Schöber test will be used to assess lumbar spine flexibility. The assessor will determine the location of the lumbosacral junction and marks it with a horizontal line. A second mark will be drown 10cm above the first line. The difference between the measurements in erect and flexion positions will be recorded. Higher differences represent better flexibility.

Total body balance will be assessed with the Flamingo test. In standing position without shoes, participants will be asked to stay on one leg. Assessor will record the number of trials needed to complete 30 seconds of this static position. The average of both legs will be used. Lower scores represent better performance

It will be assessed with theThe 6-min walk test (6MWT) to determine the maximum distance that each patient is able to walk within 6 min (in metres). Patients are instructed to walk as far as they can in 6 min, without stopping and without running, but increasing and decreasing the speed voluntarily. Higher scores represent better performance

Muscular fatigue will be assessed with the Piper Fatigue Scale-Revised (PFS-R), originally developed to assess cancer-related fatigue, but also used to assess fatigue in other musculoskeletal disorders such as heart failure. It contains 22 items scoring from 0 to 10. Total score is average score of these 22 items (0-10). Lower scores reflect better performance. PFS-R has high reliability (Cronbach's α=0.96).

Height (in centimeters) and weight (in kilograms) will be assessed and then combined to report body mass index (BMI) in kg/m^2.

Skeletal muscle mass (in kilograms) will be recorded with an impedance meter

Body fat (in percentage) will be recorded with an impedance meter

It will be assessed with the Female Sexual Function Index questionnaire (FSFI) (19 item) divided in 6 domains:desire, arousal, lubrication, orgasm, satisfaction and pain.

Items are answered on a 6-point Likert-type scale (with the exception of items 1 and 2, answered on a 5-point Likert-type scale). Scores of individual items from each domain are summed and multiplied by the domain factor. The global score is obtained by the sum of all domain scores, ranging from 2 to 36. Higher values correspond to better sexual function

It will be assessed with the Gastrointestinal Quality of Life Index (GLQI) (36 items) grouped in 5 domains: digestive symptoms, physical status, emotions, social dysfunction and effects of medical treatment. Each item is scored from 0 (worst appreciation) to 4 (best appreciation). Scores of items are summed to obtain the global score, which ranges from 0 (worst) to 144 (best quality of life).

It will be assessed with the Pittsburgh Sleep Quality Index (PSQI) (19 items), grouped in seven "components": subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Each component ranges from 0 (lowest dysfunction) to 3 (greatest dysfunction), and the PSQI global score is obtained by the sum of component's scores, and thus, ranges from 0 to 21, with higher scores indicating poor sleep quality.

Regular physical activity will be estimated through the Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ), that has shown a moderate reliability to indirectly estimate physical activity (Spearman rank correlation coefficient > 0.69). During an interview, the assessor will ask each women the number of days per week and the amount of time (in minutes) per day that they spent doing each of the 63 activities listed in the questionnaire. Finally, an activity metabolic index is calculated by multiplying the number of days per week, the amount of time per day and the standard intensity codes assigned to each activity. This score approximates Kcal/day of energy expenditure.