Several previous studies observed a positive effect of beetroot supplementation on sports performance in athletes, mainly in endurance performance. However, less attention has been paid to its effects on short-duration performance, especially in youth athletes. Moreover, only a few previous investigations performed biochemical analyses, including pro-oxidant balance assessments. It is especially important because chronic nitrate intake might directly cause the production of reactive nitrogen species and reactive oxygen species in other subcellular compartments, leading to more oxidative stress. Additionally, no previous study verified the impact of beetroot intake on sleep.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
20
Athletes received 7 days of beetroot juice supplementation with nitrate supplementation (2 × 70 mL of beetroot juice ∼12.9 mmol NO3-; Beet It, James White Drinks, Ipswich, UK) or placebo (2 × 70 mL of water with beetroot powder with negligible nitrate content).
University School of Physical Education in Cracow
Krakow, Poland
Performance test
yo-yo intermittent recovery test level 1
Time frame: 7 days after treatment
Changes in nitrates
Blood plasma will be obtained to measure nitrate concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in nitrites
Blood plasma will be obtained to measure nitrite concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in prooxidant status
Blood plasma will be obtained to measure total oxidative status
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in antioxidant status
Blood plasma will be obtained to measure total antioxidant capacity
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in oxidative stress index
The oxidative stress index will be calculated as the ratio of plasma prooxidant to antioxidant status
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in nitrooxidative stress markers
Blood plasma will be obtained to measure 3-nitrotyrosine concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in protein oxidation
Blood plasma will be obtained to measure advanced protein oxidation products concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in nucleic acid oxidation
Blood plasma will be obtained to measure ox-8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in lipids oxidation
Blood plasma will be obtained to measure thiobarbituric acid reactive substances concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in exercise-induced metabolic acidosis
Arterialized blood will be obtained to measure lactate concentration
Time frame: 1) Before the performance test 2) 3 minutes after the performance test 3) 10 minutes after the performance test 4) 20 minutes after the performance test
Objective Sleep - Time in bed
Total time spent in bed during the night assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - Sleep-onset latency
The time it takes from when the athlete intends to go to sleep and actually starts to sleep assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - Total sleep time
Total sleep time obtained from sleep onset to time at wake-up assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - Light sleep
Total amount of time in light sleep assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - Deep sleep
Total amount of time in deep sleep assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - REM sleep
Total amount of time in REM sleep assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Objective Sleep - Sleep efficiency
The percentage of total sleep time to lights off and leaving bed assessed by sleep radar
Time frame: nights 1 - 7 during treatment
Countermovement jump height
Time frame: 7 days after treatment
Ball speed velocity
Time frame: 7 days after treatment
Sprint test (0-20m)
Time frame: 7 days after treatment
Agility T-test
Time frame: 7 days after treatment
Maximal isometric handgrip strength
Time frame: 7 days after treatment
Flanker task
Time frame: 7 days after treatment
Changes in muscle damage markers
Blood serum will be obtained to measure myoglobin concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in muscle enzymes activity
Blood serum will be obtained to measure creatine kinase activity
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in inflammation markers
Blood serum will be obtained to measure C-reactive protein concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in blood count
Whole blood will be obtained to measure leukocyte count
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Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in anabolic hormones
Blood serum will be obtained to measure testosterone concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in catabolic hormones
Blood serum will be obtained to measure cortisol concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in kidney function markers
Blood serum will be obtained to measure creatinine concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in the purine metabolism marker
Blood serum will be obtained to measure uric acid concentration
Time frame: 1) baseline - 2) 7th day of treatment - before the supplementation, 3) 7th day of treatment - before the performance test, 4) 7th day of treatment - immediately after the performance test
Changes in hemoglobin concentration
Arterialized blood will be obtained to measure hemoglobin concentration
Time frame: 1) Before the performance test 2) 3 minutes after the performance test 3) 10 minutes after the performance test 4) 20 minutes after the performance test
Changes in hematocrit
Arterialized blood will be obtained to measure hematocrit
Time frame: 1) Before the performance test 2) 3 minutes after the performance test 3) 10 minutes after the performance test 4) 20 minutes after the performance test
Changes in plasma volume
The change in plasma volume will be calculated using the hemoglobin and hematocrit results
Time frame: 1) Before the performance test 2) 3 minutes after the performance test 3) 10 minutes after the performance test 4) 20 minutes after the performance test