Exercise dose, measurement reliability, and mechanistic inference in fibromyalgia trials: a critical appraisal

Fregni et al.1 published a trial examining effects of aerobic vs. non-aerobic exercise combined with tDCS on CPM and clinical outcomes in fibromyalgia. Authors address mechanistic/clinical endpoints within a rigorous framework.1 However, there are interrelated methodological/conceptual concerns that substantially affect the study's internal validity, theoretical coherence, and translational interpretation.