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).
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
60
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chemical produced naturally by the body used to rapidly regenerate ATP
A type of soluble dietary fiber that is resistant to digestion in the small intestine. It is a byproduct of the starch hydrolysis process, where starch is broken down into smaller chains of glucose molecules
Applied Science and Performance Institute
Tampa, Florida, United States
RECRUITINGMid Thigh Pull
Utilizing a pronated clean grip, subjects will be instructed to assume a body position similar to the second pull of the snatch and clean. Once body positioning is stabilized, the subject will be given a countdown. Minimal pre-tension will be allowed to eliminate slack prior to initiation of the IMTP. Each subject will perform two warm-up reps, one at 50% and one at 75% of perceived maximum effort. Thereafter, subjects will complete two maximal IMTPs separated by approximately two minutes of rest. Force kinematics from the IMTP will be collected and recorded using a linear position transducer.
Time frame: Performed one time at baseline (visit 1) and at day 56 (visit 2)
Bench Press 5 Repetition Max (RM)
Subjects will be asked to perform a 5 repetition maximum (RM) lift in order to calculate their 1RM for determination of weight needed for the protocol. The participants will start with a warm-up consisting of the following: 1 set of 8-10 reps of a light weight of their choosing followed by 1-2 sets of 3-5 reps of progressively heavier weights (\~50-70% of self-estimated 1RM). Following a 2-minute rest, subjects will select a weight they feel confident they can do for 5-7 reps but not more than 7 reps (based on warm-up weights). Weight will be increased until the subject is only able to complete 5 reps with good form. This will be their 5RM. For safety, a spotter will always be present for lifts and a set of safety bars will be used as well. Subject's 1RM will be calculated from this 5RM using the Brzycki formula (Macarilla CT, et.al. 2022) 1RM = W / (1.0278 - 0.0278 × R), where W represents the weight lifted in pounds, and R represents the number of repetitions.
Time frame: Performed one time at baseline (visit 1) and at day 56 (visit 2).
Bench Press Repetitions to Failure
After calculating the estimated 1RM from the 5RM, subjects will then perform 4 sets of bench press at 50% of the calculated 1RM to failure with a two-minute rest between all sets. Total repetitions for each of these sets will be recorded and will be used to determine fatigue and compared to follow-up Visit 2 performance for fatigue resistance. For safety, a spotter will always be present for lifts and a set of safety bars will be used as well.
Time frame: Performed one time at baseline (visit 1) and at day 56 (visit 2).
Muscle/aerobic endurance (Graded Cycling time to exhaustion)
Participants will complete a graded cycling test on a calibrated cycle ergometer to assess aerobic performance. The total duration in minutes participants are able to sustain the incremental cycling workload until volitional fatigue is recorded. This measures endurance capacity during the graded test. Proper cycle ergometer setup, including seat height and handlebar position, will be standardized for all participants. Testing will be conducted by trained technicians for consistency.
Time frame: Performed one time at baseline (visit 1) and at day 56 (visit 2).
Stroop
Subjects will complete the Stroop task electronically using the Milliseconds platform for cognitive assessment. Stroop is designed to measure executive function, cognitive flexibility, and response inhibition. It includes three conditions: simple reaction to color words, matching color and word, and identifying mismatched color-word combinations. Key metrics include simple and complex reaction times and commission errors. Faster reaction times and fewer errors reflect stronger executive control, while delayed times or errors may indicate cognitive slowing, impulsivity, or difficulty inhibiting automatic responses.
Time frame: Subjects will complete this on each of the 2 visits (baseline and day 56). Subjects will complete once before exercise protocols and once after in each session.
Abbreviated Profile of Mood States Questionnaire
Subjects will complete The Abbreviated Profile of Mood States (POMS) as an electronic 40-item self-report instrument used to assess an individual's transient emotional state across seven distinct dimensions: Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue-Inertia, Confusion-Bewilderment, Vigor-Activity (Energy), and Esteem-Related Affect. Each item is rated on a 5-point Likert scale ranging from 0 ("Not at all") to 4 ("Extremely"). Domain scores are calculated by summing item responses within each subscale. A Total Mood Disturbance (TMD) score is computed as the sum of negative mood domains (Tension, Depression, Anger, Fatigue, and Confusion) minus the sum of positive mood domains (Vigor and Esteem-Related Affect). A constant of 100 is added to the TMD score to eliminate negative values, resulting in a total score range of 0 to 200. Higher TMD scores indicate greater overall mood disturbance, whereas lower scores indicate a more favorable mood state.
Time frame: Subjects will complete once at each visit (baseline and day 56) prior to exercise protocol.
Body Composition (DXA)
Total and regional body composition will be determined by a whole-body scan on a dual-energy x-ray absorptiometry device (DXA) (Horizon A DXA System, Hologic Inc, Marlborough, MA). Each subject will be scanned by a certified technician, and the digital segmentation will be determined via computer algorithm. Fat-free mass, fat mass, and body fat percentage will be determined for each scan. Calibration will be performed against a phantom prior to testing. The abdominal region will be delineated by an upper horizontal border located at half of the distance between the acromion processes and external end of iliac crests, a lower border determined by the external end of iliac crests and the lateral borders extending to the edge of the abdominal soft tissue. All trunk tissue within this standardized height region will be selected for analysis.
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Time frame: Performed one time at baseline (visit 1) and at day 56 (visit 2).
Upper Body Muscle Soreness
A 7-point likert scale will be used for upper body muscle soreness, after performing 5 bodyweight pushups (modified for women, standard for men). The likert scale is a validated instrument designed to assess self reported muscle soreness, measured across a 7-point scale. The scale ranges from 0 (no soreness), to 6 (unbearable soreness), and has good validity and reliability (Impellizzeri, F., et al., 2007).
Time frame: Performed at the beginning of Visits 2 (day 56) and then as the only outcome for Visits 3 and 4 (days 57 and 58).
Subjective Vitality Scale (SVS)
The Subjective Vitality Scale (SVS) is a self-report measure designed to assess an individual's sense of aliveness and energy availability as a positive psychological resource. Vitality, in this context, refers to the subjective experience of feeling energized, animated, and mentally alive, and is conceptually distinguished from the absence of fatigue or negative affect. The SVS contains six-items with each item rated on a 7-point Likert scale ranging from "Not at all true" (1) to "Somewhat true" (4) to "Very true" (7). A sample item includes statements such as "I feel alive and vital." The total score is calculated as the mean of all item responses, with higher scores indicating greater levels of subjective energy and vitality. The scale has demonstrated sound psychometric properties across diverse populations and has been used extensively in research examining the effects of physical activity, social interactions, nature exposure, and motivational climates on well-being.
Time frame: Subjects will complete this on each of the 2 visits (baseline and day 56). Subjects will complete once before exercise protocols and once after in each session.
Digit Span Test (DST)
Widely used measure of short-term and working memory capacity. The investigators are using the visual presentation format. Participants are presented with sequences of digits displayed on a computer screen, each appearing briefly in succession. The test is administered in two conditions: forward and backward. In the Forward Digit Span condition, participants are asked to recall and enter the sequence in the same order it was displayed, providing a measure of short-term visual memory and sustained attention. In the Backward Digit Span condition, participants must reproduce the sequence in reverse order, placing additional demands on working memory, mental manipulation, and executive function. Higher scores indicate greater memory capacity, and the backward condition is particularly sensitive to deficits in working memory and cognitive flexibility. The visual format of the task allows for standardized, computerized administration making it well-suited for laboratory and remote testing.
Time frame: Subjects will complete this on each of the 2 visits (baseline and day 56). Subjects will complete once before exercise protocols and once after in each session.