Clinicians are under increasing pressure to base their treatment of patients on research findings—that is, to practice evidence based medicine.¹ Although some authors argue that only research from human randomised clinical trials (RCTs) should be used to determine clinical management,² an alternative is to consider the study design (RCT, cohort, basic science, etc) as one of many variables, and that no evidence should be discarded a priori. In other words, the careful interpretation of all evidence is, and has always been, the real art of medicine.³ This editorial explores these concepts using the sport medicine example of promoting stretching before exercise to prevent injury. In summary, a previous critical review of both clinical and basic science literature suggested that such stretching would not prevent injury.⁴ This conclusion was subsequently supported by a large RCT published five months later.⁵ Had the review relied only on previous RCT data, or even RCT and cohort data, the conclusions would likely have been the opposite, and incorrect.

Was there ever any evidence to suggest that stretching before exercise prevents injury? In 1983 Ekstrand et al⁶ found that a …