Acute Effects of Beetroot Juice on Isometric Knee Extension Strength, Explosive Strength and Local Muscular Endurance

Not Applicable

Completed

• Conditions: Healthy Adults
• Interventions: Dietary Supplement: Beetroot juice concentrate (140 ml); Dietary Supplement: Blackcurrant juice (placebo)

• Registration Number: NCT05567926
• Lead Sponsor: University of Primorska

Brief Summary

This is a double-blind placebo-controlled cross-over trial that aims to determine the acute effect of beetroot juice ingestion on isometric knee extension strength, explosive strength and local muscular endurance.

Detailed Description

The study aims to determine whether concentrated beetroot juice has an acute effect on isometric strength of the knee muscles and the rate of force development in knee extension, as well as endurance of the same muscle. This will be a cross-over study. 20 subjects will be randomly selected to the experimental group or control group; after 1 week, participants will repeat the measurements in the other condition. Subjects will consume 140 ml of beetroot juice extract 2.5 hours before the measurement or placebo (140 ml of blackcurrant juice with added appropriate amount of sugar to equalize the carbohydrate value and lemon juice fort the taste). An isometric dynamometer will be used to measure the isometric strength of the knee extensors. Investigators will quantify peak force, rate of force development, endurance of knee extensors at 50 % of the maximal force, and the force recovery after a fatiguing protocol.

Study Timeline

• Status Verified: 2022-10
• Study Start: 2022-10-01
• Study First Submitted: 2022-10-02
• Study First Submitted QC: 2022-10-02
• Study First Posted: 2022-10-05
• Primary Completion: 2022-10-15
• Study Completion: 2022-10-17
• Last Update Submitted: 2022-10-17
• Last Update Posted: 2022-10-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Age between 18 and 30 years
• Physically active and healthy athletes (recreational or professional)

Exclusion Criteria

• Cardiovascular, pulmonary, metabolic, neurological diseases and musculoskeletal injuries
• Smokers
• Consumption of drugs such as antacids and proton pump inhibitors in the previous 3 months
• Pregnant or breastfeeding women
• Beetroot allergic participants

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Experimental condition, receiving beetroot juice supplement	Beetroot juice concentrate (140 ml)	Participants will receive beetroot juice intervention in the experimental condition.
Placebo condition	Blackcurrant juice (placebo)	Participants will receive placebo (blackcurrant juice) in the placebo condition

Primary Outcome Measures

Name	Time	Method
Knee extension strength	2 hours after the ingestion of beetroot juice or placebo	The peak force during maximal voluntary contraction of knee extensors

Secondary Outcome Measures

Name	Time	Method
Knee extension local muscle endurance	2 hours after the ingestion of beetroot juice or placebo	Time to failure of knee muscles at 50 % of maximal force
Knee extension explosive strength	2 hours after the ingestion of beetroot juice or placebo	The rate of force development during maximal voluntary contraction of knee extensors

Trial Locations

Locations (1)

University of Primorska Faculty of Health Sciences; 🇸🇮 Izola, Slovenia