The Effects of Tyrosol and Creatine on Exercise Performance and Cognition in Healthy Adults

Summary

This study will be a randomized, double-blind, placebo-controlled trial. It will be conducted over a 8-week intervention investigating the effects of creatine (5g Creatine monohydrate); placebo control (5g resistant dextrin), and a combination group containing both creatine and tyrosol (5g creatine monohydrate + 150mg tyrosol/day). Endurance, strength, cognition, and fatigue resistance will be examined through repeated strength and endurance testing (described below). Participants who pass initial screening will be invited on-site for day one (Visit 1) of testing where the participants will proceed with a series of tests which will include the following: (1) body composition; (2) mood and cognitive testing; (3) full-body strength testing; (4) 5RM (repetition maximum) bench press, leading to multiple sets of bench press (based on the previous weight) completed to failure; (5) finally, a time to exhaustion endurance test will be conducted followed by (6) repeat cognitive testing. After the 8-week supplementation period (\~56-60 days), all original measures will be repeated as before in the same order (Visit 2). Approximately 24 hours later (Visit 3) participants will complete a questionnaire for muscle soreness remotely, and again at 48 hours post-Visit 2 (visit 4).

Detailed Description

On the day of testing, the investigators will instruct subjects to avoid high-intensity, muscle-damaging exercise for a minimum of 72-hours prior to the visit, and avoid caffeine and alcohol 12 hours prior to each study visit, and during the testing visit itself. After a minimum 8-hour overnight fast, subjects will proceed with a series of tests in the following successive order: (1) Vital Signs (heart rate, blood pressure), followed by the POMS and Subjective Vitality Scale (SVS). (2) DXA for body composition, followed by consumption of a standardized food bar snack, and at least a 15-minute break after the snack. After the 15-minute break, subjects will proceed with the following tests: (3) Digit Span Test (DST) and Stroop Test (in that successive order), which have previously demonstrated to be sensitive to creatine supplementation; (4) full-body strength measurement using a computerized mid-thigh pull; (5) Bench press, starting with determination of the subject's 5RM (repetition maximum) bench press, which will be used to calculate their 1RM. After five-minutes of rest, subjects will then perform 4-sets of bench to failure at 50 % of 1RM with a \~1-minute rest between all sets. The investigators will calculate a fatigue curve from the successive 4-sets. Importantly, the weight will be kept identical at baseline and 8-weeks to help control for training intensity, and subjects will repeat the identical warm up procedure at 8-weeks as done at baseline to help control for load. To capture shifts in total repetitions as a primary outcome, participants will be directed to reach failure on the final set of the 5RM at 8 weeks as well as all sets performed at 50% of 1RM during both baseline and 8-week assessments; (6) after an \~10-min break, subjects will then complete a time-to-exhaustion endurance testing protocol (graded cycle test). Rate of Perceived Exertion (RPE) will also be collected during the endurance protocol, using the Borg RPE scale at each stage. (7) Finally, after a \~5-min break, subjects will repeat the DST and Stroop Tests at the end of the session, followed by the SVS Scale. After the \~8 week supplementation period, all baseline measures will be repeated following baseline criteria (in the same successive order; Visit 2). Additionally, likert scales for soreness will be taken prior to DXA. Additionally, following the DXA, but prior to cognitive testing on post-testing onsite days (Visit 2), a full dosage of the study treatment will be taken with water, as well as a standardized snack which will be administered on-site by staff. The subjects will wait for at least 15 minutes after the treatment to begin the remaining tests. The likert scale for soreness will again be taken on its own at Visit 3 and 4 (Approximately 24 and 48 hours later). Additionally, subjects will be instructed to take one final serving of their treatment at a normal time of day on Visit 3.

Eligibility Criteria

Interventions