Influence of Caffeinated and Non-caffeinated Pre-workout Supplements on Resistance Exercise Performance

Inclusion criteria

• Between the ages of 18 and 40;
• Body mass between 50 - 100 kg (110-220 lb)
• Generally healthy (defined as an absence of any disease or medical condition which could potentially be negatively affected by consumption of the commercially available dietary supplements or performance of exercise, including but not limited to musculoskeletal or cardiovascular diseases).
• Resistance-trained, defined as completing 2+ resistance training sessions per week for at least three months prior to screening.
• Participants must have reported regular training of the lower body through a multi-joint exercise such as the squat or leg press at least once weekly during the three-month period prior to screening.
• Participants must have reported regular training of the bench press or chest press variation at least once weekly during the three-month period prior to screening.
• Female participants will be required to bench press ≥ 0.5 x body mass and leg press ≥ 1.75 x body mass during initial 1RM assessments to be eligible for this study.
• Male participants will be required to bench press ≥ 1.0 x body mass and leg press ≥ 3.0 x body mass to be eligible.
• Regular caffeine consumption (due to the presence of caffeine in the commercially available dietary supplement). This will be defined as an average self-reported daily intake of 250+ mg of caffeine, which is equivalent to approximately 2.5 cups of coffee.

Exclusion criteria

• Failing to meet any of the aforementioned inclusion criteria.
• Pregnant or breastfeeding (for female participants)
• Taking prescription medication which could reasonably make participation unsafe for the participant or influence study outcomes
• An inability to complete resistance exercise due to injury or medical condition
• Self-reported caffeine sensitivity, as indicated by unwanted side effects when caffeine is consumed.
• Allergy to any of the ingredients in the test beverages or standardized breakfast.
• Current use of anabolic steroids
• Presence of a pacemaker or other implanted electrical device.
• Unwillingness to wear the provided surgical mask during all testing procedures.