Objectives To describe Pilates exercise according to peer-reviewed literature, and compare definitions used in papers with healthy participants and those with low back pain. Design Asystematicreview of literature was conducted. A search for "pilates" within the maximal date ranges of the Cochrane Library, Medline, Cumulative Index to Nursing and Allied Health Literature, Physiotherapy Evidence Database, ProQuest: Nursing and Allied Health Source, Proquest: Medical and Health Complete, Scopus, Sport Discus, and Web of Science, was undertaken. To be included, papers needed to describe Pilates exercise, and be published in English within an academic, peer-reviewed journal. There were no restrictions on the methodological design or quality of papers. Content analysis was used to record qualitative definitions of Pilates. Frequencies were calculated for mention of content categories, equipment, and traditional Pilates principles. Frequencies were then compared statistically in papers with healthy participants and those with low back pain. Results 119 papers fulfilled inclusion criteria. Findings suggest that Pilates is a mind-body exercise that focuses on strength, core stability, flexibility, muscle control, posture and breathing. Exercises can be mat-based or involve use of specialised equipment. Posture was discussed statistically significantly more often in papers with participants with low back pain compared to papers with healthy participants. Traditional Pilates principles of centering, concentration, control, precision, flow, and breathing were discussed on average in 23% of papers. Apart from breathing, these principles were not mentioned in papers with low back pain participants. Conclusions There is a general consensus in the literature of the definition of Pilates exercise. A greater emphasis may be placed on posture in people with low back pain, whilst traditional principles, apart from breathing, may be less relevant.