GEPrEx

One of the biggest challenges found by scientific experiments with human beings concerns the “ideal” sample size of the study. In biostatistics, power means the probability of rejecting the null hypothesis if the null hypothesis is false. The power ranges from 0 to 1. The greater it is, the greater the chance of detecting a real difference or relationship. Often, a minimum of 0.8 is used to ensure a high probability of observing the effect of the intervention, avoiding the Type II error (i.e., accepting the null hypothesis when it is false). 

Let's imagine, for example, that a research group decided to test the hypothesis that a single bout of resistance circuit training (RCT) would be able to promote the phenomenon of post-exercise hypotension (PEH) in stroke survivors. Although the previous sample calculation indicated a minimum sample size of 23 individuals, the study was conducted with only 16 individuals. When comparing acute blood pressure (BP) responses during 120 min of recovery, there was a tendency to decrease BP after RCT (∆: - 5.5 mmHg), but without a significant difference when compared to the control session (P = 0.059). In conclusion, a single bout of RCT was unable to promote the PEH phenomenon in stroke survivors. 

The example above is a typical Type II error case, where the false null hypothesis has been confirmed. This problem could be addressed with the inclusion of at least 7 volunteers (maybe even less than that), increasing the sample size of the study to 23 individuals.

Therefore, GEPrEx decided to open a space for inviting volunteers who are interested in collaborating with the research developed by the group. The first step is to register on our website. Subsequently, volunteers will be invited to an initial visit to the lab. In this first visit, there will be a sampling based on the study's pre-established inclusion criteria. In return, the volunteers will receive a report on the evaluations carried out in the laboratory and a nutritional / sports consultancy from GEPrEx members. 

Register on the site and become a volunteer for this research!