Skip to main content
OpenTrials
Completed

NCT Number: NCT06758323

Acute Effects of Beetroot Juice and Caffeine Co-ingestion on Lower-limb Strength and Muscular Endurance in Females

The aim of this study is to evaluate the acute effects of beetroot juice and caffeine, consumed individually or in combination, on lower-limb strength and muscular endurance in physically active women. The main questions it aims to answer are:

* Does the co-ingestion of beetroot juice and caffeine enhance lower-limb strength and muscular endurance more than either substance alone or a placebo? * How do the acute effects of beetroot juice interact with caffeine on physical performance?

The study was conducted using a randomized, crossover design to evaluate the following four conditions:

Beetroot juice with placebo Caffeine with placebo Beetroot juice with caffeine Placebo only

Each participant completed all conditions, with a sufficient washout period between sessions to eliminate potential carryover effects. This design allowed for a direct comparison of the acute effects of each supplementation strategy on lower-limb strength and muscular endurance.

Participant Protocol

Participants consumed their assigned supplement on a single testing day for each condition. After supplementation, they performed standardized tests to measure lower-limb strength and muscular endurance. Progress was monitored, and data from all conditions were collected to assess the acute effects of each intervention.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Beetroot Juice Beetroot Juice with Caffeine Co-ingestion Caffeine Placebo

Age range

18 year–35 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Edificio IMIBIC Avda Menéndez Pidal s/n

Córdoba, 14004, Spain

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Minimal experience of six months of strength training
  • Be familiarized with the exercise test: counter movement jump (CMJ), barbell back squats, leg press and knee extension.

Exclusion criteria

  • Supplementation consumption
  • Sports injuries

Treatment and study plan

Beetroot juice combined with caffeine (COM)

Dietary Supplement
  • 70 mL of beetroot juice (400 mg NO3-, BEET It Sport; James White Drinks Ltd) 120 minutes before experimental session
  • 200 mg caffeine capsule from the IO.GENIX Nutrition brand (Toledo, Spain) 60 minutes before experimental session

Beetroot juice placebo with caffeine (CAF)

Dietary Supplement
  • 70 mL of a blackcurrant beverage, which depletes NO3- (Capri-Sun) 120 minutes before experimental session - 200 mg caffeine capsule from the IO.GENIX Nutrition brand (Toledo, Spain) 60 minutes before experimental session

Beetroot juice with caffeine placebo (BRJ)

Dietary Supplement
  • 70 mL of beetroot juice (400 mg NO3-, BEET It Sport; James White Drinks Ltd) 120 minutes before experimental session - Multivitamin capsule from NaturrTierra (Leganés, Spain) 60 minutes before experimental session

Beetroot placebo with caffeine placebo (PLA)

Other
  • 70 mL of a blackcurrant beverage, which depletes NO3- (Capri-Sun) 120 minutes before experimental session - Multivitamin capsule from NaturrTierra (Leganés, Spain) 60 minutes before experimental session

Primary outcomes

  1. Change of height reached in jump

    Time frame: Visit 1 (Day 1), Visit 2 (Day 5), Visit 3 (Day 9), Visit 4 (Day 13)

    Evaluated through Countermovement jump test with a recovery period of 45 seconds between jumps. The height reached was recorded in centimeters.

Secondary outcomes

  1. Movement velocity

    Time frame: Visit 1 (Day 1), Visit 2 (Day 5), Visit 3 (Day 9), Visit 4 (Day 13)

    The velocity was recorded in meters per second (m/s) during two repetitions of the back squat, evaluated at 50% and 75% of the repetition maximum (RM).

  2. Muscular endurance test

    Time frame: Visit 1 (Day 1), Visit 2 (Day 5), Visit 3 (Day 9), Visit 4 (Day 13)

    The test consists of three exercises: back squat, leg press and leg extension. Three series will be performed until concentric failure at 75% RM, three minutes of rest between each series (3 series). The number of repetitions was recorded.

  3. Rating of perceived exertion (RPE).

    Time frame: Visit 1 (Day 1), Visit 2 (Day 5), Visit 3 (Day 9), Visit 4 (Day 13)

    Immediately at the end of the muscular endurance test, participants will be instructed to report their RPE using a scale 1-10 (worse to better outcome).

Sponsors and collaborators

Lead sponsor

Jose Manuel Jurado Castro

Other

Registry information

Official study title

Effect of Beetroot Juice Supplements with Caffeine Co-ingestion on Lower-limb Strength in Females

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Jan 3, 2025
Registry last updated
Jan 6, 2025

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.

Related clinical trials

Published trials that share one or more normalized conditions with this study.