Effects of caffeine capsules and Tour Tempo music on golf-specific skill performance under mental fatigue

ISRCTN	ISRCTN15926185
DOI	https://doi.org/10.1186/ISRCTN15926185
Sponsor	Hainan Normal University
Funder	Hainan Normal University

Submission date: 27/04/2026
Registration date: 06/05/2026
Last edited: 30/04/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Signs and Symptoms

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Contact information

Mr Shiao Zhao
Scientific, Principal investigator, Public

Macao Polytechnic University
5HV2+CP8, R. de Luís Gonzaga Gomes
Macau
999078
China

Phone	+86 368564748
Email	p2314096@mpu.edu.mo

Prof Ziheng Ning
Scientific, Principal investigator

Macao Polytechnic University
5HV2+CP8, R. de Luís Gonzaga Gomes
Macau
999078
China

Phone	+86 14714947917
Email	zhning@mpu.edu.mo

Prof Xianfei Wang
Public, Scientific, Principal investigator

Hainan Normal University
No. 99 South Longkun Road
Haikou City, Hainan Province
571158
China

Phone	+86 18976037604
Email	090206@hainnu.edu.cn

Dr Guowen Ai
Public, Scientific, Principal investigator

Hainan Normal University
No. 99 South Longkun Road
Haikou City, Hainan Province
571158
China

Phone	+86 15708918980
Email	920538@hainnu.edu.cn

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Blinded (masking used)
Control	Placebo
Assignment	Crossover
Purpose	Health services research, Treatment
Scientific title	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
Study objectives	Experimentally induced mental fatigue in healthy adult male golfers through STROOP task, with a focus on its effects on golf-specific skill performance and the acute influence of caffeine capsule supplementation.
Ethics approval(s)	Approved 15/04/2026, Ethics Committee of Hainan Normal University (No.99 South Longkun Road, Haikou, Hainan, 570000, China; +86 85368564748; 920538@hainnu.edu.cn), ref: 20260005
Health condition(s) or problem(s) studied	Experimentally induced mental fatigue in healthy adult male golfers
Intervention	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 will follow the same testing order and timing structure. Putting performance will be assessed on a standardized artificial putting surface using 20 putts per session while wearing the ZZT putting training device. Performance will be quantified using mean radial error (MRE) to reflect overall putting accuracy, with lower values indicating better performance. Additional putting consistency may be evaluated using bivariate error (BVE). Golf swing performance will be assessed in an indoor golf simulator using five shots with a 7-iron and five shots with a driver in each session. Outcome measures will include shot distance, clubhead speed, and ball speed.
Intervention type	Supplement
Primary outcome measure(s)	Putting performance measured using ZZT putting training device during each experimental session at after the 30-minute Stroop task, the 15-minute audio intervention, and the standardized warm-up, before the end of the testing session.
Key secondary outcome measure(s)	Golf swing performance, including shot distance, clubhead speed, and ball speed, measured using an indoor golf simulator using five shots with a 7-iron and five shots with a driver in each session, during each experimental session at after the putting test, following the 30-minute Stroop task, the 15-minute audio intervention, and the standardized warm-up, before the end of the testing session.
Completion date	10/07/2026

Eligibility

Participant type(s)
Age group	Adult
Lower age limit	18 Years
Upper age limit	30 Years
Sex	Male
Target sample size at registration	18
Total final enrolment	22
Key inclusion criteria	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
Key exclusion criteria	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
Date of first enrolment	10/05/2026
Date of final enrolment	30/05/2026

Locations

Countries of recruitment

China

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Protocol file	version 1.1		28/04/2026	No	No

Additional files

49429_Protocol_v1.1.pdf: Protocol file

Editorial Notes

27/04/2026: Study’s existence confirmed by the Ethics Committee of Hainan Normal University, China.