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

NCT ID: NCT06935214

Last Updated: 2025-04-20

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 12 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-05-01
• Study Completion Date: 2025-12-31

Brief 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

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: DOUBLE

Study Groups

Caffeine

5 mg/kg dose of caffeine (in pill form) - Trial 1

Group Type: EXPERIMENTAL

Caffeine

Intervention Type: DIETARY_SUPPLEMENT

5 mg/kg of caffeine in pill form

Caffeine

Intervention Type: DIETARY_SUPPLEMENT

5 mg/kg dose of caffeine in pill form

Placebo

5 mg/kg dose of placebo (Maltodextrin in pill form) - Trial 2

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DIETARY_SUPPLEMENT

5 mg/kg dose of maltodextrin in pill form

Interventions

Caffeine

5 mg/kg of caffeine in pill form

Intervention Type: DIETARY_SUPPLEMENT

Placebo

5 mg/kg dose of maltodextrin in pill form

Intervention Type: DIETARY_SUPPLEMENT

Caffeine

5 mg/kg dose of caffeine in pill form

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

Exclusion Criteria

-

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

St. Mary's University, Twickenham

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Other Identifiers

SMU_ETHICS_2024-25_992

Identifier Type: -

Identifier Source: org_study_id