NCT07232628

Brief Summary

This study investigates how energy availability affects performance, injury risk, and training outcomes in elite triathletes. Over two competitive seasons (2026-2027), 40 elite and sub-elite triathletes will be monitored through physiological tests, blood samples, and questionnaires. The goal is to identify markers of low energy availability and understand its impact on health and athletic performance. The study is observational and does not involve experimental treatments. Participants continue their regular training and diet while undergoing periodic assessments.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
40

participants targeted

Target at P25-P50 for all trials

Timeline
25mo left

Started Oct 2025

Typical duration for all trials

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress22%
Oct 2025Jun 2028

Study Start

First participant enrolled

October 1, 2025

Completed
1 month until next milestone

First Submitted

Initial submission to the registry

November 14, 2025

Completed
4 days until next milestone

First Posted

Study publicly available on registry

November 18, 2025

Completed
2 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

November 30, 2027

Expected
6 months until next milestone

Study Completion

Last participant's last visit for all outcomes

June 1, 2028

Last Updated

November 18, 2025

Status Verified

November 1, 2025

Enrollment Period

2.2 years

First QC Date

November 14, 2025

Last Update Submit

November 14, 2025

Conditions

Keywords

RED-Sinjury riskperformancetriathlonbiomarker

Outcome Measures

Primary Outcomes (1)

  • T3

    Plasma triiodothyronine (T3) levels

    Two years - from off-season 2025 until in-season 2027

Secondary Outcomes (22)

  • RER

    Two years - from off-season 2025 until in-season 2027

  • Bone mineral density

    Two years - from off-season 2025 until in-season 2027

  • Fat free mass

    Two years - from off-season 2025 until in-season 2027

  • Appendicular fat free mass

    Two years - from off-season 2025 until in-season 2027

  • Fat mass

    Two years - from off-season 2025 until in-season 2027

  • +17 more secondary outcomes

Study Arms (1)

Triathletes

Elite triathletes

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodNon-Probability Sample
Study Population

Elite triathletes with a weekly training volume of more than 15 hours

You may qualify if:

  • Age ≥18 years
  • Healthy individuals
  • Training ≥15 hours/week in triathlon

You may not qualify if:

  • Smokers
  • Use of prohibited substances (WADA list) without medical justification
  • Existing injuries or illnesses that could worsen due to participation

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Institute of Sports Medicine Copenhagen, Bispebjerg Hospital

Copenhagen, Denmark

RECRUITING

Related Links

Biospecimen

Retention: SAMPLES WITHOUT DNA

Plasma and serum samples

MeSH Terms

Conditions

Relative Energy Deficiency in Sport

Condition Hierarchy (Ancestors)

Feeding and Eating DisordersMental Disorders

Central Study Contacts

Jakob Agergaard, Ph.D.

CONTACT

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Senior Researcher, Ph.D.

Study Record Dates

First Submitted

November 14, 2025

First Posted

November 18, 2025

Study Start

October 1, 2025

Primary Completion (Estimated)

November 30, 2027

Study Completion (Estimated)

June 1, 2028

Last Updated

November 18, 2025

Record last verified: 2025-11

Locations