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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Healthy Adults

Intervention / Treatment
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* Dietary Supplement: Beetroot juice concentrate (140 ml)
* Dietary Supplement: Blackcurrant juice (placebo)


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental condition, receiving beetroot juice supplement<br>Participants will receive beetroot juice intervention in the experimental condition. | Dietary Supplement: Beetroot juice concentrate (140 ml)<br>* A beetroot juice concentrate (140 ml) will be administered to participants in experimental conditions.<br>|
| Placebo Comparator: Placebo condition<br>Participants will receive placebo (blackcurrant juice) in the placebo condition | Dietary Supplement: Blackcurrant juice (placebo)<br>* 140 ml of blackcurrant juice with added appropriate amount of sugar to equalize the carbohydrate value and lemon juice fort the taste.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee extension strength | The peak force during maximal voluntary contraction of knee extensors | 2 hours after the ingestion of beetroot juice or placebo | 

Secondary Outcome Measures

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

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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isometric strength, beetroot, nitrates, local muscle endurance, supplementation