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Completed

NCT Number: NCT07611877

Ecklonia Cava Supplementation and Cycling Performance

The goal of this clinical trial (randomised, double-blind, placebo-controlled crossover study) is to investigate whether supplementation with Ecklonia cava, a natural extract derived from brown seaweed, affects exercise performance and physiological responses in trained cyclists.

The main questions it aims to answer are:

Does Ecklonia cava supplementation improve cycling performance, including power output during steady-state exercise and short maximal sprints? Does Ecklonia cava supplementation influence physiological responses to exercise, such as blood glucose, blood lactate, heart rate, and oxygen consumption?

Researchers will compare Ecklonia cava supplementation to a placebo (a look-alike substance with no active ingredients) to determine whether the supplement has any effect on performance or physiological responses.

In this crossover design, all participants will receive both the Ecklonia cava supplement and the placebo on separate occasions, with a washout period between conditions.

Participants will:

Ingest either Ecklonia cava or a placebo 30 minutes before exercise testing Complete a 60-minute cycling protocol at a moderate intensity Perform repeated short-duration maximal sprint efforts following the steady-state exercise Attend laboratory testing sessions under both supplement and placebo conditions Undergo measurements of physiological responses, including blood glucose, blood lactate, heart rate, oxygen consumption, and respiratory exchange ratio Have exercise performance assessed through measures of power output during cycling

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Key information

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Applied and Human Sciences

Kingston upon Thames, KT1 2EE, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • experienced in cycling (defined as completing at least four hours of cycle training per week with a minimum of two years of experience)

Exclusion criteria

  • Smoker
  • cardiovascular disease
  • anti-hypertensive medication

Treatment and study plan

Placebo

Dietary Supplement

Placebo Supplementation

Supplement

Dietary Supplement

Ecklonia Cava Supplementation

Primary outcomes

  1. Peak Power Output During Sprint Performance (Watts)

    Time frame: Immediately after the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Peak power output achieved during 20-second maximal sprint efforts performed following a fixed-intensity (55% Wmax) 60-minute cycling protocol

  2. Mean Power Output During Sprint Performance (Watts)

    Time frame: Immediately after the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Mean power output recorded during repeated 20-second maximal sprint efforts following steady-state cycling

  3. Blood Lactate Concentration During Sprint Cycling (mmol/L)

    Time frame: Repeated sprint cycling (3) completed immediately after the 60-minute submaximal cycling protocol, a blood sample taken 2 minutes after each sprint cycling bout. Following each 30-minute supplementation protocol.

    Blood lactate concentration measured following each repeated sprint efforts (3)

  4. Blood Glucose Concentration During Sprint Cycling (mmol/L)

    Time frame: Repeated sprint cycling (3) completed immediately after the 60-minute submaximal cycling protocol, a blood sample taken 2 minutes after each sprint cycling bout. Following each 30-minute supplementation protocol.

    Blood glucose concentration measured following repeated sprint efforts

Secondary outcomes

  1. Heart Rate During Submaximal Cycling (beats per minute)

    Time frame: During the 60-minute submaximal cycling protocol, 30 minutes after supplementation (each condition)

    Average heart rate measured during a 60-minute steady-state cycling protocol performed at 55% maximal power output

  2. Blood Lactate Concentration During Submaximal Cycling (mmol/L)

    Time frame: Every 20-minutes during the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Blood lactate concentration measured during steady-state cycling at 55% maximal power output

  3. Blood Glucose Concentration During Submaximal Cycling (mmol/L)

    Time frame: Every 20-minutes during the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Blood glucose concentration measured during steady-state cycling at 55% maximal power output

  4. Oxygen Consumption (VO₂) During Submaximal Cycling (ml/kg/min)

    Time frame: During the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Oxygen consumption measured using indirect calorimetry during steady-state cycling

  5. Respiratory Exchange Ratio (RER) During Submaximal Cycling

    Time frame: During the 60-minute submaximal cycling protocol, 30 minutes after supplementation

    Respiratory exchange ratio measured during steady-state cycling using expired gas analysis

Sponsors and collaborators

Lead sponsor

University of Exeter

Other

Collaborators

  • Kingston University

Registry information

Official study title

Acute Ecklonia Cava Supplementation Fails to Enhance Performance in Trained Cyclists

Important dates

Study start
2020
Primary completion
2020
Study completion
2020
First posted
May 28, 2026
Registry last updated
May 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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