Chronic low back pain is a common musculoskeletal problem worldwide [1] with an unfavorable prognosis [2]. Back pain is the second most prevalent health condition in Brazil [3] and is associated with high costs [4]. The etiology of low back pain is still unknown, but it is believed to be multifactorial. Therefore, degenerative, mechanical and postural conditions can be associated with low back pain [5-7]. Exercise therapy has been considered by the current clinical practice guidelines [8,9] as an effective treatment for chronic low back pain.
Exercise based upon the Pilates principles have been extensively used as an intervention for patients with chronic low back pain [6-10]. These exercises can be performed with specific apparatus (Equipment-based Pilates) or without them (Mat Pilates) [11]. Eight basic principles are considered to be essential while performing this intervention: diaphragmatic breathing, control, concentration, centering, precision, flowing movements, strength, and relaxation [12]. Previous systematic reviews on the effectiveness of the Pilates exercises in patients with low back pain revealed conflicting results [13-15]. While one review concluded that Pilates are effective for pain [13], other concluded that Pilates are effective for pain and disability [15] and finally the most recent review concluded that Pilates exercises were not effective in the reduction of pain and disability [14]. However, the authors from these reviews stated that most of the available trials are typically small and with suboptimal quality [13-15]. These issues reinforce the need for more studies on the effectiveness of Pilates exercises in the treatment of patients with chronic low back pain. To our knowledge there is no study that compared the effects of Mat-Pilates against Equipment-based Pilates in patients with chronic low back pain. The objective of this randomised controlled trial will be to compare the effectiveness of Mat Pilates and Equipment-based Pilates in the treatment of chronic non-specific low back pain patients. This study is likely to provide important information on the effectiveness and costs of these treatments as Equipment-based Pilates is more expensive than Mat Pilates for both physiotherapists and patients.