This question is about Running
Caffeine has been shown to improve performance, speed, power, and endurance capacity when consumed before a run [ 1 2 3
U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - dietary supplements for exercise and athletic performance. NIH Office of Dietary Supplements. Retrieved September 20, 2021, from https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/.
Jonathan D. Wiles, Damian Coleman, Michael Tegerdine & Ian L. Swaine (2006) The effects of caffeine ingestion on performance time, speed and power during a laboratory-based 1 km cycling time-trial, Journal of Sports Sciences, 24:11, 1165-1171, DOI: 10.1080/02640410500457687
Jane Shearer, Terry E Graham, Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal, Nutrition Reviews, Volume 72, Issue suppl_1, 1 October 2014, Pages 121–136, https://doi.org/10.1111/nure.12124