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The placebo effect is a positive outcome resulting from the belief of having received a beneficial treatment or condition, such as the belief that one has ingested caffeine to enhance sports performance []. Recently, following a consensus statement developed by different authors on the scope of the placebo effect in sport [], it has been defined as a desirable outcome derived from personal expectations and/or learned responses to a treatment, a situation, or an inert substance that leads athletes to believe they are using an ergogenic aid to achieve improved performance through an enhancement of their psychological perception []. Several neurobiological and psychological mechanisms are involved in the placebo effect [,], which can even produce improvements in the relief of subjective symptoms such as pain, fatigue, and depression []. On the other hand, the nocebo effect can arise as a negative psychobiological response to a supposed treatment [,]. The placebo effect has been extensively studied in sport [,,,,,] with most studies conducted using deceptive ergogenic aids (e.g., caffeine, carbohydrates, or sodium bicarbonate) []. Caffeine is widely used as a deceptive substance because it is one of the most commonly employed dietary supplements as an ergogenic aid for improving sports performance []. Its ergogenic effects have also been reported across a variety of sports [,,], where caffeine ingestion has been associated with improved performance. In endurance events such as running, cycling, rowing, and triathlon, caffeine has been used to produce a placebo effect due to its known ergogenic effects in these sports [,]. Thus, different authors have used caffeine as an element of suggestion for athletes in placebo studies [,,,]. During long duration exercise, where physiological requirements are predominantly aerobic, caffeine used as a placebo has been studied before. The time to complete a 4 km performance test was shorter in the caffeine reported/caffeine received and caffeine reported/placebo received conditions compared to the control condition (no intake), without differences between the two experimental conditions in time or RPE [], demonstrating a placebo effect in recreational athletes. In middle-distance trained athletes, Hurst, Schipof-Godart [] conducted a 1 km performance test with four conditions: caffeine reported/caffeine received, caffeine reported/placebo received, placebo reported/caffeine received, and placebo reported/placebo received. The time to complete 1 km was shorter in the caffeine reported/caffeine received and caffeine reported/placebo received conditions. It was also observed that participants started faster during the first half of the test, suggesting that the caffeine reported/placebo received condition exerted psychological effects and led to changes in the distribution of effort (pacing strategy). Finally, in a recent study [], 13 trained long-distance runners performed a 6-min run test under two conditions: caffeine reported/placebo received and no intake (control). The total distance covered was measured and 400 m split times were used to analyze the pacing strategy selected by the runners. The results showed that placebo ingestion improved 6-min run performance compared to the control condition, without affecting pacing. Consequently, deceptive caffeine ingestion can improve performance at intensities close to maximal aerobic speed [].