Effect of Acute Caffeine and Beetroot Juice Intake on Strength, Power, and Muscular Endurance (CAF+BJ)

University of Alcala

Status: Completed

Conditions: Caffeine; Nitrates; Resistance Exercise; Sports Performance; Dietary Supplements

Treatments: Dietary Supplement: Acute beetroot juice; Dietary Supplement: Acute caffeine and beetroot juice; Dietary Supplement: Placebo; Dietary Supplement: Acute caffeine

Study type: Interventional

Funder types: Other

Identifiers

NCT06596395

CEIP/2023/4/093

Details and patient eligibility

About

Introduction: Several studies have evaluated and confirmed the ergogenic effect of acute caffeine and beetroot juice intake on sports performance. However, there are few studies focused on the production of strength, power, and muscle endurance, particularly when both supplements are ingested together.

Objectives: Evaluate the acute effect of combined and isolated intake of caffeine and beetroot juice on the production of strength, power, and muscle endurance in young adults, analyzing the effect of circadian rhythms (morning vs. afternoon) on the exercise performed (bench press vs. squat).

Methods: A total of 12 healthy and physically active participants will be recruited for the study. Through a double-blind, crossover, randomized, and controlled design, participants will ingest: a) Caffeine (3 mg/kg body mass); b) Beetroot juice (70 ml, 6.5 mmol of nitrates); c) Caffeine + Beetroot juice; d) Placebo (maltodextrin, 3 mg/kg). The supplements will be ingested 120 minutes (beetroot juice or placebo) and 60 minutes before (caffeine or placebo), the latter dissolved in 200 ml of water. After the ingestion period, strength, power, and muscle endurance will be analyzed with 1RM tests, strength and power tests at 25%, 50%, 75%, and 90% 1RM, and muscle endurance tests at 65% 1RM, in all cases for squat and bench press exercises. Additionally, dynamometry (manual and the isometric mid-thigh pull test) and vertical jump (squat jump and countermovement jump) will be analyzed. The four experimental conditions will be conducted in the morning (8:00 am to 10:00 am) and in the afternoon (4:30 pm to 6:30 pm).

Enrollment: 14 patients

Sex: Male

Ages: 18 to 35 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Age between ≥ 18 and ≤ 35 years.
• Body Mass Index (BMI) < 25 kg/m².
• Resistance-trained individuals (> 2 years of structured trained).
• Healthy men and women without neurological, cardiometabolic, immunological, or physical conditions that prevent them from exercising.
• Participants must be able to perform the tests described in the following section.

Exclusion criteria

• History of neuromuscular diseases, heart diseases, or diseases that may affect liver or muscle metabolism.
• Use of drugs, other stimulants or sport supplements that interfere with the intake of the study's dietary supplements.
• Sedentary habits (< 150 min/week of moderate exercise).
• Having undergone prolonged periods of forced physical inactivity during the 6 months prior to the study.
• Performing strenuous exercise during the 48 hours prior to the tests.
• Failure to replicate the same food intake on the two days of the experiments.
• Consuming caffeine or any other stimulant after 6 pm the day before the training or tests, to avoid headaches, discomfort, or lethargy among regular caffeine consumers.
• Consuming foods rich in NO3- (e.g., beetroot, spinach, or celery) during the 48 hours prior to each experimental condition.

Trial design

Primary purpose: Other

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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14 participants in 4 patient groups, including a placebo group

Caffeine + Beetroot Juice

Experimental group

Description:

70 mL of concentrated NO3--rich (BJ, 6.5 mmol NO3-) + 3 mg/kg of caffeine

Treatment:

Dietary Supplement: Acute caffeine and beetroot juice

Beetroot Juice

Experimental group

Description:

70 mL of concentrated NO3--rich (BJ, 6.5 mmol NO3-) + 3 mg/kg of placebo (maltodextrin)

Treatment:

Dietary Supplement: Acute beetroot juice

Caffeine

Experimental group

Description:

70 mL of NO3--depleted (BJ, 0.04 mmol NO3-) + 3 mg/kg of caffeine

Treatment:

Dietary Supplement: Acute caffeine

Placebo

Placebo Comparator group

Description:

70 mL of NO3--depleted (BJ, 0.04 mmol NO3-) + 3 mg/kg of placebo (maltodextrin)

Treatment:

Dietary Supplement: Placebo