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Who should be blinded?
  1. C Gissane
  1. Department of Health Studies, Brunel University Osterley Campus, Isleworth Middlesex TW7 5DU, United Kingdom
    1. Roger Eston,
    2. Ann Rowlands
    1. School of Sport, Health and Exercise Sciences University of Wales Bangor, Gwynedd LL57 2PX

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      Editor,—I was very pleased to read the recent article by Eston and Rowlands1 on the various stages of development of a research project. It is important to have papers on research methodology that deal specifically with sports science/medicine examples.

      Even though the authors described the paper as “a brief guide to the most common sequence of stages”,1 it nevertheless addressed many good points about research design. However, their description of blinding was perhaps oversimplified, disregarding experimental design in some areas of sports medicine research. They stated that in a single blind study the participants do not know which treatment they are receiving, and in double blind studies neither the participants nor the tester know which treatment the participants are receiving.

      Research in sport and exercise medicine encompasses a number of professions, who differ in the way they provide treatments and interventions. In some of these disciplines, the way the intervention is administered will prevent researchers from blinding the investigation as described in the paper. Recent work on the design of randomised clinical trials has suggested that a study may be described as single blind if one of the groups of people involved does not know which intervention has been given to each participant.2 It was added that it may be the investigators assessing the outcomes that are blinded.

      A recently published paper sought to determine the effects of stretching before exercise on lower limb injury.3 The authors of this study were able to claim that the study was single blind, despite the fact that all participants were aware of the intervention they were receiving. The blinding was achieved by masking the practitioner who diagnosed the injuries to the patient allocation. Blinding the examiner rather than the patient is a common practice when there is no other way to disguise the specific treatment.

      A traditional view may state that blinding must be carried out as described by Eston and Rowlands.1 However, the design strategy needs to be flexible enough to incorporate the distinctive features of the intervention under investigation.

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      Authors' reply

      Editor,—Thank you for providing us with the opportunity to reply to this letter. We agree entirely with the observations. We were referring to the traditional view of “blinding”, which is more common in the sports and exercise science scenario. Dr Gissane is quite justified in bringing this to our attention, and we thank him for his interest and positive comments.

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