Mental FatigueNCT07779304
Mental Fatigue, Attentional Focus, and Countermovement Jump Performance
A study testing Mental-Fatigue Protocol (Stroop Task), No Prescribed Focus Instruction and Internal Focus Instruction in people with Mental Fatigue and Athletic Performance, run by Inonu University at 1 site in Turkey (Türkiye).
Trial summary
This study examines whether short-term mental fatigue and different jump instructions affect how high people can jump. Thirty-two physically active university students will complete two testing sessions in random order: one after a 30-minute mentally tiring computer task and one after a 30-minute relaxing video. Read more about this study
- Who is it for?
- Ages 18 to 30 yearsHealthy volunteers can take part
- Conditions the study is for
- Mental Fatigue, Athletic Performance
- What is being tested?
- Mental-Fatigue Protocol (Stroop Task), No Prescribed Focus Instruction and Internal Focus Instruction
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 32 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Sep 2026to 1 Nov 2026
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 30 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age 18-30 years
- Third- or fourth-year undergraduate student in the Faculty of Sport Sciences, İnönü University
- Engaged in structured physical activity on at least 2 days per week
- Normal or corrected-to-normal vision and normal color vision
- Able to safely perform maximal vertical jumps
Who cannot join
- Major lower-extremity surgery or injury
- Musculoskeletal injury during the preceding 6 months that could affect jumping
- Diagnosed neurological, psychiatric, or cardiovascular disorder
- Regular use of medication that could influence alertness, fatigue, cardiovascular responses, or neuromuscular performance
- Any health condition compromising safety or measurement validity
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
İnönü University, Faculty of Sport Sciences
Malatya, 44280
Oguzhan BOZKURT, PhD, +90 532 620 23 24, oguzhan.bozkurt@inonu.edu.tr
Oguzhan BOZKURT, PhD
About this study
Official title: The Effects of Acute Mental Fatigue and Attentional Focus Instructions on Countermovement Jump Performance
This study examines whether short-term mental fatigue and different jump instructions affect how high people can jump. Thirty-two physically active university students will complete two testing sessions in random order: one after a 30-minute mentally tiring computer task and one after a 30-minute relaxing video. In both sessions, participants will perform vertical jumps while receiving one of three types of instructions: no special instruction, focusing on their own body movements, or focusing on pushing the ground away. The study will compare jump height across these conditions to better understand how mental tiredness and coaching cues affect jumping performance, which may help coaches and athletes design better training and competition preparation.
Read the detailed description
This study uses a sex-stratified, randomized, counterbalanced crossover design with repeated measures to examine the effects of acute mental fatigue and attentional-focus instructions on countermovement jump (CMJ) performance. Thirty-two physically active undergraduate students (16 women, 16 men), aged 18-30 years, will be enrolled from the Faculty of Sport Sciences at İnönü University, Malatya, Türkiye.
Each participant will complete two experimental protocols, separated by at least 72 hours: a control protocol (approximately 30 minutes of passive viewing of a narration-free nature video) and a mental-fatigue protocol (a 30-minute computerized color-word Stroop interference task). Protocol order will be randomized and stratified by sex. In both protocols, participants will perform CMJs under three attentional-focus conditions, presented in a randomized order that is held constant within each participant across sessions: no prescribed focus, internal focus (attention directed to the participant's own body movements), and external focus (attention directed to the effect of movement on the environment). CMJ height will be recorded in centimeters using a validated video-based jump-analysis application (My Jump Lab) on a tablet camera recording at 240 frames per second, with the higher of two valid trials retained as the primary outcome for each protocol-by-focus condition.
Subjective mental fatigue will be assessed immediately before and after each protocol using a 0-10 visual analogue scale to confirm the effectiveness of the fatigue manipulation. Stroop task performance (total trials, accuracy) and adherence to the assigned attentional-focus instructions will be recorded as secondary measures.
The primary analysis will use a 2 (protocol: control, mental fatigue) x 3 (focus: no prescribed, internal, external) x 2 (sex: women, men) mixed-model ANOVA on CMJ height, with protocol and focus as within-participant factors and sex as a between-participant factor. Reporting will follow CONSORT 2025 and the CONSORT extension for randomized crossover trials.
- Conditions
- Mental Fatigue, Athletic Performance
- Being tested
- Mental-Fatigue Protocol (Stroop Task), Control Protocol (Nature Video), No Prescribed Focus Instruction, Internal Focus Instruction, External Focus Instruction
- Keywords
- Countermovement Jump, Attentional Focus, Stroop Task, Crossover Design, Vertical Jump Performance, Cognitive Fatigue
- Medical subject headings
- Mental Fatigue
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Mental-Fatigue Protocol (Stroop Task)Behavioural
Also called Color-Word Stroop Task
A 30-minute computerized color-word Stroop interference task delivered as one uninterrupted block on a custom program, in which participants identify the font color of color-word stimuli while ignoring word meaning, inducing acute mental fatigue prior to countermovement jump testing.
Control Protocol (Nature Video)Behavioural
Approximately 30 minutes of passive viewing of a narration-free nature video under standardized lighting, seating, and sound conditions, serving as the non-fatiguing control condition matched in duration to the mental-fatigue protocol.
No Prescribed Focus InstructionBehavioural
A verbal cue delivered before each jump attempt with no directional attentional instruction: "When you are ready, jump as high as possible."
Internal Focus InstructionBehavioural
A verbal cue delivered before each jump attempt directing attention to the participant's own body movements: "When you are ready, focus on extending your knees and hips as quickly and explosively as possible while jumping as high as possible."
External Focus InstructionBehavioural
A verbal cue delivered before each jump attempt directing attention to the effect of movement on the environment: "When you are ready, focus on pushing the ground away from you as quickly and explosively as possible while jumping as high as possible."
| Study group | Role | What they receive |
|---|---|---|
| Control-First Sequence | Experimental | Participants complete the control protocol (30-min passive nature-video viewing) in the first session and the mental-fatigue protocol (30-min Stroop task) in the second session, separated by at least 72 hours. In both sessions, participants perform countermovement jumps under three attentional-focus conditions (no prescribed focus, internal focus, external focus) in a randomized, participant-fixed order. Receives: Behavioral: Control Protocol (Nature Video); Behavioral: No Prescribed Focus Instruction; Behavioral: Internal Focus Instruction; Behavioral: External Focus Instruction |
| Mental-Fatigue-First Sequence | Experimental | Participants complete the mental-fatigue protocol (30-min Stroop task) in the first session and the control protocol (30-min passive nature-video viewing) in the second session, separated by at least 72 hours. In both sessions, participants perform countermovement jumps under three attentional-focus conditions (no prescribed focus, internal focus, external focus) in a randomized, participant-fixed order. Receives: Behavioral: Mental-Fatigue Protocol (Stroop Task); Behavioral: No Prescribed Focus Instruction; Behavioral: Internal Focus Instruction; Behavioral: External Focus Instruction |
What is being measured
The primary outcome is the main question the study is designed to answer.
Countermovement Jump Height
Vertical jump height, measured in centimeters, recorded using a validated video-based jump-analysis application (My Jump Lab) at 240 frames per second. The higher of two valid trials in each protocol-by-attentional-focus condition (control vs. mental fatigue x no prescribed focus, internal focus, external focus) will be retained as the outcome value for that condition.
Measured: Assessed once per attentional-focus condition (higher of two valid trials) approximately 30 seconds after completion of each 30-minute protocol (control or mental fatigue), across two sessions separated by at least 72 hours.
Secondary outcomes (3)
Subjective Mental Fatigue Rating
Self-reported mental fatigue rated on a 0-10 visual analogue scale, in response to "How mentally fatigued do you feel right now?" (0 = not mentally fatigued at all, 10 = the highest possible level of mental fatigue).
Measured: Immediately before and immediately after each 30-minute protocol (control and mental fatigue), across two experimental sessions separated by at least 72 hours.
Stroop Task Performance
Total trials completed, number of correct and incorrect responses, and accuracy (%), recorded automatically by the Stroop task software during the mental-fatigue protocol.
Measured: Continuously recorded throughout the 30-minute mental-fatigue protocol, administered in one of the two experimental sessions per participant (protocol order randomized).
Focus-Instruction Adherence
Self-reported adherence to the assigned attentional-focus instructions, rated on a 0-10 visual analogue scale.
Measured: Assessed once per attentional-focus condition, immediately after completion of each 30-minute protocol (control or mental fatigue), across two experimental sessions separated by at least 72 hours.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2026
- Study start1 Sep 2026 (estimated)
- Primary completion1 Oct 2026 (estimated)
- Study completion1 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Mental FatigueStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Each participant completed both the control and mental-fatigue protocols in a counterbalanced order (crossover). Within each protocol, participants performed countermovement jumps under three attentional-focus conditions (no prescribed focus, internal focus, external focus), presented in one of six randomized orders held constant for each participant across both sessions.
- Masking
- None (open label)
- Enrolment
- 32 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Inonu University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Oğuzhan Bozkurt, Inonu University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07779304
- Sponsor's protocol ID
- INU-2026-10953
- Other IDs
- 2026/10953
- Status last verified
- Aug 2026
- First submitted
- 17 Aug 2026
- Last updated
- 21 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No