NCT06935214

The Repeatability of the Effect of Caffeine Supplementation on Submaximal Physiological Responses and Cycling Time Trial Performance

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 12 (estimated)
• Sponsor: St. Mary's University, Twickenham · Academic / Other
• Sex: Male
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

Recently, Grgic (2018) discussed the concept of responders and non-responders to caffeine supplementation highlighting the importance of the repeatability of results. However, the number of studies that have investigated this idea by repeating the same time-trial performance test multiple times with the same caffeine dose is sparse (Astorino et al., 2012; Del Coso et al., 2019). Furthermore, studies have shown that differences in the CYP1A2 genotype may account for some of the variation in time-trial performance (Guest et al., 2018). Thus, the current study aims to identify whether the effects of moderate caffeine supplementation (5 mg/kg) on time-trial performance are repeatable to aid the identification of responders and non-responders. Additionally, the study aims to determine if the CYP1A2 genotype may explain any of the variability in time-trial performance in trained male cyclists.

Conditions

• Caffeine

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Caffeine	5 mg/kg of caffeine in pill form
DIETARY_SUPPLEMENT	Placebo	5 mg/kg dose of maltodextrin in pill form
DIETARY_SUPPLEMENT	Caffeine	5 mg/kg dose of caffeine in pill form

Timeline

• Start date: 2025-05-01
• Primary completion: 2025-08-23
• Completion: 2025-12-31
• First posted: 2025-04-20
• Last updated: 2025-04-20