Sports Performance
Conditions
Keywords
L-tyrosine, Caffeine, Boxing, BDNF, Cognitive performance, Anaerobic performance
Brief summary
Participants will complete six sessions, including one familiarization and baseline session followed by five experimental conditions: control (no supplementation), placebo, L-tyrosine, caffeine, and combined L-tyrosine plus caffeine. The experimental conditions will be performed in a randomized, counterbalanced crossover design with a washout period of at least 72 hours between sessions. Resting physiological and cognitive assessments will be performed during the familiarization session, while biochemical, cognitive, and boxing-specific performance assessments will be conducted before and after each experimental session.
Detailed description
Participants will attend six sessions in total. The first session will be used for familiarization and baseline assessments, including anthropometric measurements, resting physiological measurements, and cognitive performance testing. The remaining five sessions will consist of one control condition (no supplementation) and four randomized experimental conditions (placebo, L-tyrosine, caffeine, and combined L-tyrosine plus caffeine) administered in a randomized, counterbalanced crossover design. Each experimental session will be separated by a washout period of at least 72 hours. During the placebo, L-tyrosine, caffeine, and combined supplementation conditions, the assigned intervention will be administered 60 minutes before exercise. No supplement will be administered during the control condition. Before and immediately after each experimental session, venous blood samples will be collected to assess brain-derived neurotrophic factor (BDNF) and oxidative stress biomarkers, including total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx). Cognitive performance will be evaluated using the computerized Stroop test, and boxing-specific physical performance will be assessed using a standardized boxing simulation protocol. Heart rate and rating of perceived exertion (RPE) will also be recorded during the exercise protocol.
Interventions
DIETARY_SUPPLEMENTPlacebo
Placebo solution matched in taste and volume to active supplements.
DIETARY_SUPPLEMENTL-Tyrosine
L-tyrosine at 150 mg/kg body weight administered 60 minutes before exercise.
DIETARY_SUPPLEMENTCaffeine
Caffeine at 5 mg/kg body weight administered 60 minutes before exercise.
DIETARY_SUPPLEMENTL-tyrosine + Caffeine
Combined L-tyrosine (150 mg/kg) and caffeine (5 mg/kg) administered 60 minutes before exercise.
Sponsors
Inonu University
Ataturk University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Masking description
Both participants and investigators are blinded to the supplementation conditions. Supplements are prepared and coded by an independent researcher to ensure double-blind conditions.
Intervention model description
Participants will complete five experimental conditions (control, placebo, L-tyrosine, caffeine, and combined L-tyrosine plus caffeine) in a randomized, counterbalanced crossover design. Each experimental session will be separated by a washout period of at least 72 hours to minimize potential carryover effects.
Eligibility
Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Male elite boxers aged ≥18 years At least 8 years of boxing training experience Active participation in national or international competitions Regular training schedule No injury or illness affecting performance
Exclusion criteria
Use of nutritional supplements or stimulants within the last 4 weeks Any cardiovascular, metabolic, or neurological disorder Current injury or musculoskeletal limitation Smoking or excessive caffeine intake Failure to comply with study procedures
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Stroop Test Performance | up to 12 weeks | Cognitive performance assessed using the Stroop test, including reaction time and accuracy. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| BDNF Levels | up to 12 weeks | Serum brain-derived neurotrophic factor levels measured before and after exercise. |
| Oxidative Stress Markers | up to 12 weeks | Serum levels of total antioxidant status (TAS), total oxidant status (TOS), malondialdehyde (MDA), superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity will be measured. |
Countries
Turkey (Türkiye)
Contacts
CONTACTHalil UÇAR
Outcome results
None listed