Mental Fatigue, Attentional Focus, and Countermovement Jump Performance

NCT07779304 | Not Yet Recruiting

• 2 other identifiers: INU-2026-109532026/10953
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Mental Fatigue; Athletic Performance

Keywords

Countermovement Jump; Attentional Focus; Stroop Task; Crossover Design; Vertical Jump Performance; Cognitive Fatigue

Outcome Measures

Primary Outcomes (1)

• 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.

  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

  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

  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

  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.

Study Arms (2)

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.

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.

Behavioral: Mental-Fatigue Protocol (Stroop Task); Behavioral: No Prescribed Focus Instruction; Behavioral: Internal Focus Instruction; Behavioral: External Focus Instruction

Interventions

Mental-Fatigue Protocol (Stroop Task) BEHAVIORAL

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.

Also known as: Color-Word Stroop Task

Mental-Fatigue-First Sequence

Control Protocol (Nature Video) BEHAVIORAL

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.

Control-First Sequence

No Prescribed Focus Instruction BEHAVIORAL

A verbal cue delivered before each jump attempt with no directional attentional instruction: "When you are ready, jump as high as possible."

Control-First Sequence; Mental-Fatigue-First Sequence

Internal Focus Instruction BEHAVIORAL

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."

Control-First Sequence; Mental-Fatigue-First Sequence

External Focus Instruction BEHAVIORAL

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."

Control-First Sequence; Mental-Fatigue-First Sequence

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Inonu University: lead

Study Sites (1)

İnönü University, Faculty of Sport Sciences

Malatya, 44280, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Mental Fatigue

Interventions

Stroop Test

Condition Hierarchy (Ancestors)

Fatigue; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavioral Symptoms; Behavior

Intervention Hierarchy (Ancestors)

Neuropsychological Tests; Psychological Tests; Behavioral Disciplines and Activities

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 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.

Study Record Dates

• First Submitted: August 17, 2026
• First Posted: August 21, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): November 1, 2026
• Last Updated: August 21, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)