The Repeatability of the Effect of Caffeine Supplementation on Submaximal Physiological Responses and Cycling Time Trial Performance
Trial Snapshot
- Phase
- Not Applicable
- Status
- Not yet recruiting
- Enrollment
- 12
- Primary Endpoint
- Blood lactate concentration
Study Overview
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Double (Participant, Investigator)
Eligibility Criteria
- Ages
- 18 Years to 35 Years (Adult)
- Sex
- Male
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •To be considered for inclusion in the study, participants must be regular cyclists, between 18 and 35 years of age, capable of completing a 20 km cycling time trial at a minimum speed of 30 km/h (arbitrary inclusion criteria to ensure a sufficient standard of athlete).
Exclusion Criteria
- Not provided
Arms & Interventions
Caffeine
5 mg/kg dose of caffeine (in pill form) - Trial 1
Intervention: Caffeine (Dietary Supplement)
Placebo
5 mg/kg dose of placebo (Maltodextrin in pill form) - Trial 2
Intervention: Placebo (Dietary Supplement)
Outcomes
Primary Outcomes
Blood lactate concentration
Time Frame: From baseline to completion, up to 31 days
Description: Change from baseline in blood lactate concentration measured at rest and at six different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
Heart rate
Time Frame: From baseline to completion, up to 31 days
Change from baseline in heart rate measured at rest and at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer.
Oxygen uptake
Time Frame: From baseline to completion, up to 31 days
Change from baseline in oxygen uptake measured at rest and at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
Perceived exertion
Time Frame: From baseline to completion, up to 31 days
Change from baseline in rating of perceived exertion measured (using the 6-20 Borg scale) at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
Time trial completion time
Time Frame: From baseline to completion, up to 31 days
Change from baseline in time to complete a time trial at a target amount of work on an electromagnetically-braked cycle ergometer calculated from the power output at maximal oxygen uptake and designed to last approximately 25 minutes.
Secondary Outcomes
No secondary outcomes reported