Acute Physical Exercise Intensity on Cognitive Inhibition and Psychological Well-being in Adolescents

Participants The initial sample comprised 35 students from 2nd grade of high school (19 boys and 16 girls), aged between 16 and 18 years (M =16.49, SD = .79). The students belonged to a public school of a large city in Spain.

Ethical approval and informed consent The experiment was approved by the Ethics Committee of the authors' university and approved by the corresponding academic authority of the high school. All participants signed an informed consent by themselves and their parents.

Measures Measure of Interference Index (Stroop Test). The interference index was calculated from the scores obtained by the participants in the Spanish adaptation of the Stroop test 25 using a pencil-and-paper version.

The test consists of three pages of words and drawings printed in colors that combine in different ways. The first set or page, called Word (W), is made up of the words blue, green, and red, written in black ink on a white background. The second page, called Color (C), presents groups of four Xs (XXXX), printed in one of the above-mentioned colors (blue, red or green). The participants are requested to name the color of the four Xs presented. The last page, called Word-Color (WC) is made up of the names of the colors that appear on page 1, but in ink colors that are incongruent with the printed word. Participants are requested to name the color while inhibiting the reading of the word.

All the pages have 100 items, and each test lasts 45 seconds. The number of hits is added. For this study, we calculated the interference index with the formula, Interference Index = WC - ((WxC)/(W+C)). As indicated by Martín et al. (2012), this index represents the difference between the real performance on page 3 and the expected performance as a function of the hits on pages 1 and 2. Higher values indicate better control of interference.