How the time between repeated soccer headers affects brain and eye health
Defining the Role of Repetitive Head Impact Time Intervals in Mitigating Subconcussive Neural Injury
This test sees if shorter (24-hour) versus longer (72-hour) gaps between repeated soccer headers change brain and eye measures in current soccer players who routinely head the ball.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 102 (estimated) |
| Ages | 18 Years to 35 Years |
| Sex | All |
| Sponsor | Indiana University Academic / other |
| Locations | 1 site (Bloomington, Indiana) |
| Trial ID | NCT07010887 on ClinicalTrials.gov |
What this trial studies
This randomized, controlled human-laboratory experiment exposes experienced soccer players to standardized repetitive head impacts with either short (24-hour) or long (72-hour) intervals between impact clusters over four weeks. Researchers will collect blood and biofluid samples for proteomic and transcriptomic biomarkers, perform retinal imaging (OCT), ocular-motor testing (convergence and pupillometry), and record qEEG with a BrainScope device. Outcomes will be measured acutely after impacts, cumulatively after repeated exposures across four weeks, and during a two-week post-exposure follow-up. The design isolates direction, magnitude, and frequency of impacts to test how time between clusters influences cellular, physiological, and functional integrity.
Who should consider this trial
Good fit: Ideal candidates are current soccer players (intercollegiate, club, intramural, or recreational) with at least five years of heading experience who can provide informed consent and complete study procedures.
Not a fit: Individuals with a head, neck, or face injury or concussion within the past six months, or those with eye diseases affecting retinal blood vessels (for example glaucoma, macular degeneration, or diabetic retinopathy), are excluded and unlikely to benefit from participation.
Why it matters
Potential benefit: If successful, the findings could identify safer timing for repetitive head-impact exposure and help reduce cumulative brain and eye changes in people who head the ball frequently.
How similar studies have performed: Prior research has shown that repeated subconcussive impacts can produce biomarker and ocular changes, but using randomized interval comparisons to test 24‑ versus 72‑hour spacing is a novel application of those methods.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Current soccer player (intercollegiate, club, intramural, recreational). * At least 5 years of soccer heading experience (justification below). * Ability to provide informed consent without a legally authorized representative (LAR). Exclusion Criteria: * Any head, neck, or face injury within the 6 months prior to enrollment, including concussions, that precludes participation in contact sports. * Participants with eye conditions or diseases that could impact the blood vessels in the eye -such as but not limited to: glaucoma, macular degeneration, diabetic retinopathy. * Determination that the participant is unsuitable for study entry or potentially unable to complete all aspects of the study based on the judgement of the Investigator.
Where this trial is running
Bloomington, Indiana
- Indiana University School of Public Health — Bloomington, Indiana, United States (Recruiting)
Study contacts
- Principal investigator: Keisuke Kawata, PhD — Indiana University Bloomington Department of Kineseology
- Study coordinator: Keisuke Kawata, PhD
- Email: kkawata@indiana.edu
- Phone: 812-855-5244
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.