2.1. Participants
Asthenia, FMS, fibromyalgia, Pain
FIBROMYALGIA, FIBROMYALGIA, FMS
The sample was selected from patients diagnosed with FMS who were registered in the “Aragonese Association of Chronic Asthenia and Fibromyalgia”. The inclusion criteria were to have been diagnosed with FMS by a rheumatologist according to the “American College of Rheumatology” (ACR) criteria [We based our sample size calculation on an expected between group difference that would correspond to a large effect (Cohen’s d = 0.80) on the response of GH to exercise. Based on a significance level of 5% and a statistical power (1-β) = 0.80 in a two-tailed test, we needed 26 FMS patients in each group. In line with previous research in which around 85% of participating women with fibromyalgia tolerated a moderate to high–intensity aerobic exercise programme [The study protocol complied with the legal requirements in force at the time the study was carried out in Spain (RD 561/1993; BOE 1993). The RCT was conducted according to the “Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials” (IMMPACT) recommendations. All procedures performed in this study were in accordance with the 1964 Helsinki Declaration and its subsequent amendments, as well as the ethical standards for exercise and sport science research [