Acute and Chronic Effects of Static and Dynamic Stretching on Flexibility and Neuromuscular and Functional Performance in Healthy Subjects: a Blinded and Randomized Clinical Trial

It is a randomized, blinded clinical trial where the first researcher (P1) was responsible for assessments and reassessments; the second searcher (P2) at randomization and inquiry of the subjects in the intervention protocol and the third investigator (P3) for the statistical analyzes.The research was conducted at the Laboratory of therapeutic practices of the Department of Physical Therapy, Federal University of Rio Grande do Norte (UFRN) and started after the approval of the ethics committee.The sample was recruited by convenience by written disclosure, electronics and personal contact in academies and higher education institutions in the city of Natal / RN. The volunteers were randomly distributed through the electronic site http://www.randomization.com (Code: 21318). Two pieces of information were inserted, namely: the sample size and the number of groups. With this data, the site has generated a specific encoding for each group and distributed the subjects randomly into three groups: static stretching (gAE); dynamic stretching (gAD) and control (gC).

Sample size calculation

For the sample size calculation was used G * Power 3.1.0 software and the procedures followed the recommendations of studies prévios45. Based on a pilot study of four volunteers, it has adopted a power of 0.95, considering a significance level of 5%, a correlation coefficient of 0.5, and 0.25 effect size for both, It calculated a "n" sample of 15 individuals for each group ("n" sample = 45). This analysis was performed to reduce the chance of Type II error and to determine the minimum number of individuals required for this investigation. Thus, the sample size was sufficient to provide 95.5% statistical power.

Procedures and evaluation measures

At first all subjects were recorded in the survey through an evaluation form containing information on identification, weight, height, injury history and physical activity .