This is a randomized parallel trial and a qualitative study developed by the Laboratório de Investigação Fisioterapêutica Clínica, Departamento de Fisioterapia, Fonoaudiologia e Terapia Ocupacional, Faculdade de Medicina, Universidade de Sao Paulo. The study and informed consent terms were both approved by the Research Ethics Committee of the Faculdade de Medicina, Universidade de Sao Paulo, and both were registered at ClinicalTrials.gov (NCT02384603)—start date of recruitment: February 2016. This work was completed in March 2018.

Individuals with FM who were residents in the metropolitan area of São Paulo, Brazil, and referred to the Departamento de Fisioterapia, Fonoaudiologia e Terapia Ocupacional, Faculdade de Medicina, Universidade de Sao Paulo, were enrolled in the study. The inclusion criteria were adults between 30 and 60 years of age, a diagnosis of FM according to the American College of Rheumatology (ACR) 2010 criteria [27], and the presence of at least 11 of 18 tender points. The exclusion criteria were simultaneous physical therapy, the presence of joint deformities, and an inability to walk independently. A total of 101 eligible participants were identified.

The sample size calculation (SigmaPlot 12.3 software, Systat Software Inc.) was performed based on the visual analog pain scale data included in a study conducted by the research group [28]: paired t-test, a detectable change of 2.0 ± 2.9 cm between baseline and posttreatment, and a level of significance of 0.05 and power of 0.80, resulting in a sample size of 19 adults in each group. The study hypothesis was that both methods of muscle stretching exercises, used in concert with an educational approach, could be beneficial to FM patients.

To balance the number of participants in the two groups, block randomization (subjects in blocks of four at a time) was used for the sequence generation process [29]. An excerpt from a table of random two-digit numbers was created using SigmaPlot 12.3 software (Systat Software Inc.). Sequentially numbered, opaque, sealed envelopes were used to conceal the group allocations prior to the assignment. The researcher in charge of randomly assigning the participants was not blinded and did not participate in the outcome assessment evaluation, but participated in the intervention or analysis. The outcome evaluator was blinded to the randomization process and the participants’ allocation. The evaluator was a physiotherapist who received training in this kind of evaluation. The participants were informed about their designated group and were instructed not to inform the evaluator. The participants also did not contact each other and were blinded to the hypothesis of the study. It was not possible to hide each participant’s designation from the physiotherapist involved in the treatment.

Assessment

The evaluation was made at the beginning and end of the 10-week treatment period. The modified diagnostic ACR 2011 criteria are indicated as an evaluation instrument in clinical and epidemiological studies [30]. The criteria, which were applied during an interview, consisted of the following: (I) the Widespread Pain Index (WPI), representing the sum of body sites referred to as painful in the last week and ranged from zero to 19, and (II) the Symptom Severity Score (SSS), representing the sum of the scores of other disorders (fatigue, cognitive problems, sleep disorders in the last week, and three somatic symptoms, i.e., abdominal pain, depression, and headache in the last 6 months) and can vary from zero to 12. A patient satisfies the ACR 2011 criteria for FM with the following scores: WPI ≥ 7 and SSS ≥ 5 or WPI of 3–6 and SSS ≥ 9.

Primary outcome variable Pain intensity

Pain intensity was evaluated with the Visual Analog Scale for Pain (VAS) [31, 32] consisting of a 10-cm long horizontal line, with “no pain” on the far left and “unbearable pain” on the far right. Each patient was asked to mark the line indicating the pain intensity at the moment. The minimum score was zero, and the maximum was 10.

Secondary outcome variables Multidimensionality of pain

The pain dimensions were assessed with the McGill Pain Questionnaire (MPQ) [33], which consisted of 78 words describing the quality of pain and were organized into 20 groups that formed three dimensions: sensory, affective, and evaluative. Each word was assigned an intensity value on a numerical scale of one to five points. A patient was asked to choose the word in each group that described the pain at the moment, with “none” as an option. The maximum scores of the dimensions were as follows: sensory = 41, affective = 14, and evaluative = 5. The higher the score, the greater the intensity of the pain.

Pressure pain threshold at tender points

The pressure pain threshold at tender points was evaluated by dolorimetry with a dolorimeter (FDX, Wagner Instruments®) that measured the pain threshold (i.e., the value of the lowest pressure at which a patient-reported pain). The patients’ pain threshold was assessed at 18 tender points according to the ACR FM classification criteria [1] by applying progressively greater pressure perpendicular to the surface of the skin at a rate of approximately 1 kg/cm2/s. Each patient was instructed to state when the feeling of pressure turned into pain. With the patient seated, the tender points of the base of the occipital, lower cervical, trapezius, supraspinatus, second costochondral joint, lateral epicondyle, and medial border of the knee were assessed bilaterally. The patient was asked to stay upright to evaluate the tender points of the gluteus and the greater trochanter.

Attitudes of patients toward chronic pain

The Survey of Pain Attitudes (SOPA)-Brief Version [34] consists of 30 items corresponding to seven domains of attitudes, beliefs, and behaviors toward pain: Control, Emotion, Disability, Harm, Medication, Solicitude, and Medical cure. In this study, the evaluator used the instrument, and the patients indicated their agreement with each assertion on a five-point Likert-type scale ranging from zero to four. The score of each domain was calculated as the sum of the points of the answers to each item divided by the number of items answered. The final average score for each domain ranged from zero to 4. There are no cutoff points and no right or wrong answers. The guidelines define certain more desirable responses that are considered hypothetically more adaptive by the author of the inventory. The desirable score orientations for each domain after adjustment were as follows: Control = 4, Emotion = 4, Disability = 0, Harm = 0, Medication = 0, Solicitude = 0, and Medical cure = 0.

Impact of FM on quality of life

The Fibromyalgia Impact Questionnaire (FIQ) was used [35] to measure the impact of FM on patient’s quality of life. This scale consisted of 19 items organized into 10 questions about the most recent week, which were then used to evaluate physical function, well-being, lack of work, difficulty with work, and intensity of symptoms. The calculation of the total score was as follows: Question 1 = (sum of the values of the items) × 10 ÷ 30 + Question 2 = (inversion of the value) × 10 ÷ 7 + Question 3 = (value) × 10 ÷ 7 + Questions 4 to 10 = the value of each question. The maximum total score was 100. The higher the score, the worse a patient’s quality of life.

Body posture

Body posture evaluation was conducted by photogrammetry with the Postural Assessment Software Protocol (PAS/SAPO) [36, 37]. The camera (Cyber-shot DSC-W230, Sony®) was positioned on a tripod at a distance of 1.50 m with the lens at the height of the patient’s umbilical line. The following body posture measurements were analyzed and interpreted according to the protocol introduced by Duarte et al. [38]: right lateral view: (a) horizontal alignment of the head (position of head in relation to trunk, wherein lower values refer to greater head forward position); (b) vertical alignment of trunk (positive values indicate anterior trunk tilt, while negative values indicate the opposite); (c) vertical body alignment (positive values indicate anterior body tilt, while negative values indicate the opposite); anterior view: (d) horizontal alignment of head; (e) horizontal alignment of acromia; and (f) horizontal alignment of the anterior superior iliac spine. For the last three measurements, the software reference value is zero, and the positive and negative values indicate tilting to the right and left, respectively.

Flexibility

Flexibility was assessed with the sit-and-reach test [39, 40], which utilized a Wells bench (Sanny®). Each patient was asked to sit on the floor with legs extended, without shoes, feet apart, leaning against the bench, arms at shoulder level, and hands overlapping. The patient reached as far as possible along the measurement line of the Wells bench, keeping the knees in extension. The measure of the second attempt was recorded. The higher the value, the greater the flexibility of the patient.

Postural control

The Modified Clinical Test of Sensory Interaction on Balance (mCTSIB) was used to assess postural control and was performed on a pressure platform (NeuroCom Balance Master®) [41]. This test evaluated static balance under four sensory conditions while each patient was instructed to stand quietly erect, with arms straight alongside the body and with bare feet in the position recommended by Neurocom: eyes open and stable surface, eyes closed and stable surface, eyes open and unstable surface, eyes closed and unstable surface. The center of gravity sway velocity (degrees/second) corresponds to the sum of the anteroposterior and mediolateral sway measured for 10 seconds per trial. The mean value of the three measures of the center of gravity sway velocity under each of the four sensory conditions was considered. The sum of the means divided by the number of conditions (mCTSIB mean) was used. The mean value was provided by version 8.3.0 of the Balance Master® operating system. In this measurement tool, the higher the center of gravity sway velocity, the worse the postural control.

Perception and body self-care

Audio recording of the story: All the patients reported on how they perceived their bodies and posture and took care of their bodies. The reports were audio-recorded for transcription.

Treatments

The FM patients attended 10 individual treatment sessions, each approximately 80 min long, once a week for 10 weeks. To maximize adherence to treatment, individualized attention, such as phone calls after missed sessions, was given to each patient. More than three consecutive absences were considered discontinuation of therapy.

A physiotherapist with 15 years of experience in FM clinical research and in the educational area, who is a specialist in the global posture reeducation method developed by Philippe-Emmanuel Souchard [11], led the cognitive behavioral therapy-based educational approach and muscle stretching exercises for both groups. She was trained in this approach by the researcher-in-chief (PhD in Experimental Psychology) and had a background in teaching coping skills regarding health for adults and elderly adults.

The treatments are described in Table 1. In all sessions, the cognitive behavioral therapy-based educational approach was employed. This approach involved a structured educational methodology [42] based on the following three references: (I) the conditions offered by the physiotherapist, (II) the expected outcome of the activity, and (III) the real outcome of the activity of the week. The acquisition and maintenance of coping skills were enhanced by the convergence of items II and III. In addition, the physiotherapist worked with patients to identify dysfunctional and negative thought patterns, as well as the underlying maladaptive attitudes or beliefs fueling those thoughts. Positive perspectives were emphasized with the patients.

Table 1 Report on muscle stretching exercises used in concert with an educational approach

The first three sessions were common to both treatments. The first session was solely educational. The second and third sessions contained body/postural awareness and proprioception exercises, which were preparations for the stretching exercises.

Data analysis

Data were analyzed using descriptive and inferential statistics, with α < 0.05. Excel for Windows (Microsoft) and SigmaPlot 12.3 (Systat Software Inc.) were used. The variables were tested for normal distributions using the Shapiro–Wilk test.

The differences between groups at posttreatment were analyzed using t, chi-square, or Mann–Whitney tests. The differences between the baseline and posttreatment values for each group were analyzed using the paired t-test or the Wilcoxon Sign Rank test.

An evaluation of clinically important differences was conducted by estimating the rate of change in the scores of the variable [44]: Clinical improvement (%) = [(outcome variable score after treatment − outcome variable score at baseline) ÷ (outcome variable score at baseline)]. A cutoff of 30% was defined a priori as the minimal relevant clinical improvement for pain [45]. For the Fibromyalgia Impact Questionnaire score, a 14% improvement was considered relevant for the total score [46]. Meanwhile, in the perception and body self-care reports transcription analysis, we used the domains of the Survey of Pain Attitudes—Brief Version [34] as classes of meanings to describe the perceptions and body self-care reports of the FM patients [47].