Author(s): VALERO MARTINEZ, F, GONZÁLEZ-MOHÍNO, F., AGUDO-ORTEGA, A., SALINERO, J.J., Institution: UNIVERSIDAD DE CASTILLA LA MANCHA, Country: SPAIN, Abstract-ID: 984

INTRODUCTION:
The potential for enhancing sports performance through the placebo effect has been studied from several perspectives including nutritional and mechanical ergogenic aids (Hurst et al. 2020). Most of the research has been conducted on strength and power-based exercises, while endurance performance has received less attention. However, the occurrence and magnitude of the placebo effect may be affected by sex, although the evidence is limited and sometimes conflicting and these studies have been conducted in medical settings (Enck & Klosterhalfen, 2019; Shafir et al. 2022). The aim of this study was to analyze the existing literature on the placebo effect and endurance sports, with a special focus on the presence of women.
METHODS:
The search for published studies on the topic was conducted in the databases Pubmed and Scopus on 10th January 2024. Search terms included Mesh terms and free-text words, for key concepts related to placebo effect and endurance sports. Titles and abstracts were screened for subsequent full-text review. Thirteen studies were selected from the search results based on the following inclusion criteria: inclusion of at least one endurance test and a comparison between a placebo-deceptive condition and a control condition. All studies involved cycling (n=7) or running (n=6) tests and included a total of 229 participants (208 men, 21 women).
RESULTS:
Contradictory results were found regarding the effects of placebos on endurance performance. Out of the 13 studies reviewed, 8 reported positive placebo effects. Endurance cycling performance was analyzed in tests from 1 km to 40 km time trial, and 3 out of 7 found a significant placebo effect. Endurance running performance was studied in tests from ≈ 3 to 50 min, where 5 out of 6 found a significant placebo effect. Overall, only 3 studies included women (all were running studies), and no one reported sex-analysis or individual data. In addition, only 9.2% of the total sample were women. The mean sample size in individual studies was 17.6±10.9 participants (median=13) with women comprising only 1.6±3.7 (median=0).
CONCLUSION:
There is limited research on endurance performance, with varying test durations, and women are almost excluded.

REFERENCES:

1. Hurst, P., Schipof-Godart, L., Szabo, A., Raglin, J., Hettinga, F., Roelands, B., Lane, A., Foad, A., Coleman, D., & Beedie, C. (2020). The Placebo and Nocebo effect on sports performance: A systematic review. European Journal of Sport Science, 20(3), 279–292
2. Enck, P., & Klosterhalfen, S. (2019). Does Sex/Gender Play a Role in Placebo and Nocebo Effects? Conflicting Evidence From Clinical Trials and Experimental Studies. Frontiers in Neuroscience, 13.
3. Shafir, R., Olson, E., Colloca, L. (2022). The neglect of sex: A call to action for including sex as a biological variable in placebo and nocebo research. Contemporary Clinical Trials, 116.