Sample Size To calculate the sample size was calculated as the average change in pain intensity referred to the global active stretching group at the end of the first and eighth week of treatment. The mean and standard deviation of the intensity of pain at the end of the first week was 4.88 SD 3.056 and at the end of the eighth week 0.85 SD 1.875 (Martins & PINTO E SILVA, 2005 b) The assumption is that the effect of treatment with yoga is similar to that found with the global active stretching.