Acute effects of caffeine capsules with and without Tour Tempo music on golf-specific skill performance under mental fatigue: a randomized, placebo-controlled crossover trial
Experimentally induced mental fatigue in healthy adult male golfers
This registration concerns the caffeine-capsule experiment only. Each participant will complete four experimental conditions in a randomised crossover order: caffeine capsule plus Tour Tempo music, caffeine capsule plus no music, placebo capsule plus Tour Tempo music, and placebo capsule plus no music. Consecutive experimental visits will be separated by a washout period of at least 7 days. Randomisation will be performed at the level of treatment sequence. A balanced Latin-square/Williams-type sequence will be used to counterbalance the order of the four conditions and reduce period and carryover effects. An independent researcher who is not involved in outcome assessment will generate the sequence allocation using random.org or an equivalent computer-generated randomisation procedure. Participants will be assigned to the sequences in approximately equal numbers. The allocation list will be kept in a password-protected file by the independent researcher. If paper allocation is used, sequentially numbered opaque sealed envelopes will be prepared. Caffeine will be administered as a 3 mg/kg body-mass dose in capsules approximately 60 minutes before the golf performance tests. Placebo capsules will contain Nutricost maltodextrin, with each capsule containing 200 mg of maltodextrin and no caffeine. The placebo capsules will be matched to the caffeine capsules in appearance, capsule size, colour and administration procedure as closely as possible. Capsule preparation, coding and dispensing will be completed by an independent researcher, and participants and testing staff will be blinded to capsule condition. Tour Tempo music will be delivered through Bluetooth headphones for 15 minutes using a fixed participant-selected track. In the no-music condition, participants will wear the same headphones for the same duration without music. A 30-minute Stroop task will be used to induce mental fatigue before the audio/warm-up period and golf performance tests. All sessions wil
1. Healthy adult male golfers with regular golf practice experience 2. Aged 18 years or older 3. Self-reported 18-hole scores between 90 and 100 4. Normal vision and no colour blindness 5. Low habitual caffeine intake (<50 mg/day) 6. Free from cardiovascular or neurological disease 7. Free from any acute injury that could affect golf swing or putting performance
1. Known caffeine allergy or marked caffeine intolerance 2. Arrhythmia, uncontrolled hypertension, or other conditions making caffeine intake unsuitable 3. Recent musculoskeletal injury affecting golf swing or putting performance (e.g., shoulder, elbow, wrist, low back) 4. Current use of medications affecting the central nervous system or heart rate 5. Hearing impairment that would interfere with standardized audio delivery