Athletic Performance, Cognitive Fatigue, Exercise Recovery, Football-Specific Performance, Perceptual-cognitive Performance
Conditions
Keywords
Phosphatidylserine, Taurine, Caffeine, Football players, Soccer, Responder analysis, Heart rate variability, LnRMSSD, Reaction time, Mental fatigue, Sports nutrition, Individual responsiveness, Decision-making, Perceptual-cognitive performance, Recovery
Brief summary
This study will examine whether a 28-day supplementation protocol containing taurine, caffeine, and phosphatidylserine can help professional male football players maintain physical performance, cognitive function, recovery-related readiness, and selected football-specific perceptual-cognitive performance. Participants will be randomly assigned to receive either placebo or a phosphatidylserine-containing multi-ingredient supplement. Before and after the supplementation period, players will complete non-invasive assessments such as sprint testing, reaction-time testing, heart rate variability monitoring, wellness/readiness questionnaires, mental-fatigue measures, and selected football-specific perceptual-cognitive tasks where available. The study is designed as an external validation and extension of responder profiles derived from previous randomized controlled trials. Data from previous trials and this validation cohort will be used to examine whether baseline physical, cognitive, autonomic, fatigue-related, recovery-related, or perceptual-cognitive characteristics can predict which players are most likely to benefit from phosphatidylserine-containing multi-ingredient supplementation.
Detailed description
This is a randomized, double-blind, placebo-controlled validation study conducted in professional male football players. The study is designed to externally validate and extend individual responder profiles previously derived from randomized controlled trials investigating taurine-, caffeine-, and phosphatidylserine-containing supplementation in professional football players. Participants in the validation cohort will be randomly assigned to receive either placebo or a phosphatidylserine-containing multi-ingredient supplement containing taurine, caffeine, and phosphatidylserine. Phosphatidylserine will be provided at a dose of 600 mg per day. The supplementation period will last 28 days. The placebo will be matched as closely as possible in appearance, number of units, packaging, and administration schedule. The main aim of the study is to determine whether baseline characteristics can help identify players who are more likely to respond positively to the supplementation protocol. The multidimensional responder profile will include predefined domains related to physical performance and fatigue resistance, cognitive and mental fatigue-related outcomes, recovery/readiness-related outcomes, and selected football-specific perceptual-cognitive performance. Before and after the supplementation period, participants will complete non-invasive assessments. These may include 30 m sprint performance, simple or choice reaction time, computerized cognitive tasks, mental fatigue ratings, heart rate variability indices such as LnRMSSD, wellness/readiness questionnaires, sleep quality, perceived fatigue, and selected football-specific performance variables where available. The perceptual-cognitive domain may include football-specific decision-making accuracy, response time, tactical inhibitory decision-making under cognitive load, situational awareness, visual search-related variables, and selected field-transfer outcomes where available. These measures will be used to explore whether players who respond favorably in physical or recovery-related domains also show favorable responses in cognitive fatigue resistance, decision-making, or perceptual-cognitive football performance. No blood, saliva, urine, genetic material, or other biological samples will be collected. All assessments will be non-invasive. The validation cohort will test whether responder profiles developed from previous trials can be applied to an independent group of professional football players. The study may support a more individualized approach to performance nutrition by identifying whether baseline autonomic, cognitive, fatigue-related, recovery-related, or perceptual-cognitive characteristics are associated with a greater likelihood of response to phosphatidylserine-containing multi-ingredient supplementation.
Interventions
OTHERPlacebo
Matching placebo capsules administered orally once daily for 28 consecutive days. The placebo was matched to the active supplements in appearance, number, packaging, and administration schedule.
DIETARY_SUPPLEMENTTaurine
Taurine 1500 mg/day administered orally once daily in capsules for 28 consecutive days.
DIETARY_SUPPLEMENTCaffeine
Anhydrous caffeine 200 mg/day administered orally once daily in capsules for 28 consecutive days.
DIETARY_SUPPLEMENTPhosphatidylserine
Phosphatidylserine 600 mg/day administered orally once daily in capsules for 28 consecutive days.
Sponsors
Vizja University in Warsaw
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
Participants, investigators, supplementation supervisors, outcome assessors, coaches rating tactical performance, and the statistician will be blinded to group allocation. Placebo and active supplement capsules will be identical in appearance, number, packaging, and administration schedule. Supplement packs will be coded so that group allocation cannot be identified by participants, club staff, investigators, or outcome assessors. The randomization code will be kept by an independent person not involved in recruitment, supplement distribution, outcome assessment, or statistical analysis and will be revealed only after completion of data collection and primary analyses.
Intervention model description
Participants will be randomly assigned in a 1:1:1 ratio to placebo, taurine plus caffeine, or taurine plus caffeine plus phosphatidylserine 600 mg/day for 28 days. The study will use a randomized, double-blind, placebo- and active-controlled, parallel-group design. This validation cohort will be used to test and extend predefined multidimensional responder profiles in professional football players, with particular focus on identifying players most likely to benefit from the addition of phosphatidylserine to taurine-caffeine supplementation.
Eligibility
Sex/Gender
MALE
Age
18 Years to 37 Years
Healthy volunteers
Yes
Inclusion criteria
* Male professional or highly trained football players aged 18-37 years. * Regular participation in structured football training and team activities. * Minimum of 5 years of structured football training experience. * Regular involvement in club training during the study period. * Medical clearance or no known contraindications to high-intensity exercise testing. * Ability to complete sprint, reaction-time, cognitive-fatigue, heart-rate-variability, wellness/readiness, and selected football-specific perceptual-cognitive assessments where available. * Willingness to maintain usual diet and training habits during the study period. * Willingness to avoid additional ergogenic supplements outside the study protocol during the intervention. * Willingness to follow caffeine restrictions before testing sessions. * Written informed consent provided before participation.
Exclusion criteria
* Current musculoskeletal injury or illness preventing full participation in training or testing. * Musculoskeletal injury within the previous 3 months that may affect sprint, football-specific performance, or perceptual-cognitive testing. * Cardiovascular, metabolic, neurological, psychiatric, or other chronic disease that may affect safety or study outcomes. * Diagnosed sleep disorder. * Use of medication affecting heart rate, autonomic nervous system function, sleep, cognition, or exercise performance. * Known hypersensitivity or intolerance to caffeine, taurine, phosphatidylserine, or any supplement ingredient. * Regular use of ergogenic supplements that cannot be discontinued before and during the study period. * Smoking or regular use of nicotine products. * Participation in another interventional study during the same period. * Inability to comply with supplementation, monitoring, or testing procedures. * Failure to provide written informed consent.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Proportion of Participants Classified as Multidimensional Responders After 28 Days | Baseline to post-intervention after 28 days of supplementation | Proportion of participants classified as multidimensional responders after 28 days of supplementation. A multidimensional responder will be defined as a participant meeting the predefined response criterion in at least two of four domains: physical performance/fatigue resistance, cognitive fatigue-related performance, recovery/readiness, and football-specific perceptual-cognitive performance. The outcome will be reported as the percentage of participants classified as multidimensional responders in each group. Unit of Measure: percentage of participants |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in 30 m Sprint Time | Baseline to post-intervention after 28 days of supplementation | Change in 30 m sprint performance from baseline to post-intervention testing. Sprint time will be measured using electronic timing gates. Participants will perform three maximal 30 m sprint trials separated by standardized recovery periods, and the best valid trial will be used for analysis. |
| Change in Cognitive Fatigue Task Reaction Time | Baseline to post-intervention after 28 days of supplementation | Change in reaction time during the computerized cognitive fatigue task from baseline to post-intervention testing after 28 days of supplementation. Reaction time will be measured during the predefined cognitive task performed under cognitive load. The outcome will be reported as the mean change in reaction time from baseline to post-intervention testing. Lower values indicate faster cognitive responses. Unit of Measure: milliseconds |
| Change in Perceived Mental Fatigue VAS Score | Baseline to post-intervention after 28 days of supplementation. | Change in perceived mental fatigue from baseline to post-intervention testing after 28 days of supplementation. Perceived mental fatigue will be assessed using a 0-10 visual analogue scale, where 0 indicates no perceived mental fatigue and 10 indicates maximal perceived mental fatigue. The outcome will be reported as the mean change in score from baseline to post-intervention testing. Higher scores indicate greater perceived mental fatigue. Unit of Measure: points on a 0-10 scale |
| Change in Final 3-Day Mean LnRMSSD | Baseline monitoring period to final 3 days of supplementation. | Change in heart rate variability from baseline monitoring to the final 3 days of supplementation. Heart rate variability will be expressed as the natural logarithm of the root mean square of successive RR interval differences. Morning HRV will be recorded under standardized resting conditions. The outcome will be reported as the mean change in final 3-day mean LnRMSSD compared with the baseline monitoring period. Unit of Measure: ln(ms) |
| Change in Readiness-to-Train Rating Scale Score | Baseline monitoring period to final 3 days of supplementation. | Change in self-reported readiness to train from baseline monitoring to the final 3 days of supplementation. Readiness to train will be assessed using a single-item readiness-to-train rating scale scored from 1 to 10, where 1 indicates very poor readiness and 10 indicates excellent readiness. The outcome will be reported as the mean change in readiness-to-train score from the baseline monitoring period to the final 3-day supplementation period. Higher scores indicate greater perceived readiness to train. Unit of Measure: points on a 1-10 scale |
| Change in Hooper and Mackinnon Wellness Questionnaire Fatigue Item Score | Baseline monitoring period to final 3 days of supplementation. | Change in self-reported fatigue from baseline monitoring to the final 3 days of supplementation. Fatigue will be assessed using the fatigue item of the Hooper and Mackinnon wellness questionnaire. The item is scored on a 1-7 scale. The outcome will be reported as the mean change in fatigue item score from the baseline monitoring period to the final 3-day supplementation period. Higher scores indicate greater perceived fatigue. Unit of Measure: points on a 1-7 scale |
| Area Under the Receiver Operating Characteristic Curve for the Predefined Responder Model | Post-intervention after 28 days of supplementation. | Predictive performance of the predefined responder model in the independent validation cohort will be assessed using the area under the receiver operating characteristic curve. The model will compare predicted responder status with observed multidimensional responder status after 28 days of supplementation. Higher values indicate better discrimination. Unit of Measure: area under the curve |
| Number of Participants With Supplement-Related Adverse Events | During the 28-day supplementation period | Number of participants reporting at least one supplement-related adverse event during the 28-day supplementation period. Participants will be asked to report gastrointestinal symptoms, sleep disturbances, headache, palpitations, nervousness, or any other unusual symptoms. Unit of Measure: participants |
| Change in Football-Specific Video Decision-Making Task Response Time | Baseline to post-intervention after 28 days of supplementation. | Change in response time during the football-specific video decision-making task from baseline to post-intervention testing after 28 days of supplementation. Response time will be measured as the time from presentation of the decision prompt to participant response. The outcome will be reported as the mean change in response time from baseline to post-intervention testing. Lower values indicate faster football-specific decision-making. Unit of Measure: milliseconds |
| Change in Football-Specific Video Decision-Making Task Accuracy | Baseline to post-intervention after 28 days of supplementation. | Change in football-specific decision-making accuracy from baseline to post-intervention testing after 28 days of supplementation. Decision-making accuracy will be assessed using a football-specific video decision-making task. Participants will view standardized football-specific scenarios and select the most appropriate tactical decision. The outcome will be reported as the mean change in the percentage of correct decisions from baseline to post-intervention testing. Higher values indicate better football-specific decision-making accuracy. Unit of Measure: percentage of correct decisions |
| Change in Eye-Tracking Time to First Fixation on the Optimal Tactical Option | Baseline to post-intervention after 28 days of supplementation. | Change in visual search behavior from baseline to post-intervention testing after 28 days of supplementation. Visual search behavior will be assessed using eye-tracking during the football-specific video decision-making task. Time to first fixation will be defined as the time from scenario onset to the first fixation on the predefined optimal tactical option. The outcome will be reported as the mean change in time to first fixation from baseline to post-intervention testing. Lower values indicate faster visual orientation toward the optimal tactical option. Unit of Measure: milliseconds |
Countries
Poland
Contacts
CONTACTKrzysztof Maciej Mizera, PhD
Outcome results
None listed