**Are cognitive benefits of preceding acute bouts of endurance exercise a placebo effect? Methods** The experimental protocol is approved by the ethics committee of the German Sport Science University (Cologne, Germany). In accordance to the declaration of Helsinki, all participants will sign written informed consent prior to participation. **Sample size calculation** Sample size calculation was conducted for potential group differences of participants expectations towards the specific treatment they were allocated to regarding cognitive benefits. Accordingly, sample size calculation was based on the main effect of between-subjects factor treatment (moderate exercise vs. vigorous exercise vs. waiting vs. reading vs. video vs. light exercise vs. stretching vs. self-myofascial release training) in a variance analytic model (ANOVA). An effect of f=.25 which corresponds to a medium effect following Cohens classification (Cohen, 1988) was used for this study`s sample size calculation. Assuming that an effect of this size or bigger really does exist within the population of young healthy individuals, the risk of not obtaining it in our empiric sample (Type II error rate (β)) was set at β=.2 (accordingly test power as 1- β was set at .8). Assuming that this effect really does not exist in this population, the risk of still obtaining significant results in our sample (Type I error rate and level of significance level (α), respectively) was set at α=.05. Under the presuppositions made, sample size calculation revealed that 240 participants should be included in the study equally distributed to the eight groups. **Participants** Participants will be asked to participate in a computer-based survey on the effects of a leisure activity on subsequent cognitive performances lasting about 15 minutes. Participants will not receive course credit or comparable advantages for participation. However, participants will receive a 1.50 € coffee voucher for their participation in the study. Inclusion criteria for study participation comprises of age between 18 and 35 years and German as mother tongue. Subjects will be excluded from study participation if they report any form of chronic or acute disease, any limitation in their ability to exercise, if they misunderstood the described treatment or a cognitive testing task, if they report having knowledge about the link between acute endurance exercise. M**aterials and Procedure** The examination will be conducted in the neuropsychological testing laboratory of the Institute of Sports Medicine and Circulation Research of the German Sport Science University (Cologne, Germany). Prior to investigation, participants will be handed out an information sheet containing detailed description of intended study procedures. Participants will be given sufficient time to read the information sheet carefully and they had opportunity to address any questions or concerns about participation. The examination will be conducted via a computer-based survey using the Media Lab software version 2016 (Empirisoft, NY, USA). First, participants will read about one of eight treatments (see table 2): supervised bicycle ergometer training session at moderate intensity, supervised bicycle ergometer training session at vigorous intensity, sitting alone in a room waiting, sitting alone in a room reading, sitting alone in a room watching an exercise related video, supervised bicycle ergometer training session at light intensity, supervised stretching and coordination training session, supervised myofascial release training session. For each treatment, it will be stated that it would take approximately 30 minutes of time. Subjects will be randomly assigned to one of the eight treatment groups. After the written explanation of the treatment, participants will watch a short video that will give visual expression of the key elements of the treatment (see supplement). Subsequently, on a separate screen and without being able to view the descriptions or the video of the treatment again, participants will be asked briefly to describe the treatment to ensure their comprehension. Participants then will read about and will watch videos of cognitive tasks most commonly used in studies examining cognitive benefits of acute endurance exercise: the Stroop task, the Trail Making Test (TMT) part B and a free recall task (see supplement for videos). After each test description and video, participants will be asked briefly to describe the cognitive task ensuring participants task comprehension. Subsequently, participants will rate what effect on their performance in that particular task they would expect if they had received the previously described treatment. Participants will answer on a 9-point Likert scale ranging from “very negative effect” to “very positive effect”. The scales mid-point is labelled as “no effect”. The order of the cognitive tasks will be randomly but counterbalanced across participants. In the following, participants will be asked if they exercise regularly and if they have ever read or heard about research, showing that acute endurance exercise can improve cognitive performances. Finally, participants will provide anthropometric and demographic information. A pdf version of an English translation of the original German survey is provided in supplement. Two coders will independently judge participants comprehension of the treatment and the cognitive tasks. Participants will be excluded if either coder thinks that they should be excluded. Data will be analyzed using a variance analytic model investigating the effect of between-subjects factor treatment (moderate exercise vs. vigorous exercise vs. waiting vs. reading vs. video vs. light exercise vs. stretching and coordination vs. self-myofascial release training) on participants expectations. Partial eta-square values will be reported as effect size estimates. If one-way ANOVA reveals significant main effect of factor treatment this will be further investigated using Bonferroni corrected post-hoc pairwise comparisons. For all pairwise comparisons Cohen`s d values will be reported as effect size estimates. Potential differences between groups regarding potentially confounding factors age, weight, height and BMI will be analyzed using separate one-way ANOVAs. Potential group differences regarding distribution of gender and current occupation will be examined using separate Fischer exact tests. Potential group differences regarding education level will be investigated using Kruskal-Wallis test. All descriptive and inferential statistical analyses will be conducted using SPSS 22 (IBM, Armonk, NY, USA).