Nitrate Supplementation on Motor Unit Activity

Study Overview
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Brief Summary
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This study aimed to assess if nitrate supplementation influence motor unit (MU) activity following a sustained ischemic contraction and whether this is affected by blood flow restriction (BFR) during the recovery period. Fourteen male participants (mean ± SD, 25 ± 6 years) completed two experimental trials following 5-days of supplementation with either nitrate-rich (NIT) or nitrate-depleted (PLA) beetroot juice in a randomized, double-blinded, cross-over design. Intramuscular electromyography was used to assess MU potential (MUP) size and firing rates (MUFR) during a submaximal (25% MVC) sustained isometric contraction with BFR. These variables were also assessed during a 90 s recovery period with the first half completed with, and the second half completed without, BFR. Nitrate supplementation can expedite the recovery of MUP duration following a sustained ischemic contraction in healthy adults. These novel observations improve understanding of the effects of nitrate on the recovery of neuromuscular function post-exercise and might have implications for recovery of muscle contractile function.

Official Title
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Influence of Nitrate Supplementation on Motor Unit Activity During Recovery Following a Sustained Ischemic Contraction.

Conditions
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Dietary Supplements, Healthy

Intervention / Treatment
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* Dietary Supplement: Nitrate supplementation
* Dietary Supplement: Placebo supplementtaion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male between 18 - 30 years free from known respiratory insufficiency, cardiovascular disease and neuro-musculo-skeletal problems at present or in the preceding 6 months. having at least 5 years competitively (team) sport experience. Exclusion Criteria: having cardiovascular disease, neuromuscular disease and any lower limb injury and treatment for chronic respiratory complaints.

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

Sexes Eligible for Study
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Male

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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Nitrate supplementation<br>2 × 70 mL/day shots of concentrate nitrae-rich ( 12.8 mmol/day NO3-) beetroot juice. Two shots were supplemented for 5 days; one each morning ( 9 am) and one each evening ( 9 pm) except for the day of the experimental trial when both shots were taken together 2.5 h before the experimental trial. | Dietary Supplement: Nitrate supplementation<br>* Participants ingested 2 × 70 mL/day shots of concentrate nitrate-rich ( 12.8 mmol/day nitrate) or nitrate-depleted ( 0.08 mmol/day nitrite) beetroot juice (Beet It, James White Drinks Ltd., Ipswich, UK). Two shots were supplemented for 5 days; one each morning ( 9 am) and one each evening ( 9 pm) except for the day of the experimental trial when both shots were taken together 2.5 h before the experimental trial.<br>|
| Placebo Comparator: Placebo supplementation<br>2 × 70 mL/day shots of concentrate nitrate-depleted ( 0.08 mmol/day NO3-) beetroot juice. Two shots were supplemented for 5 days; one each morning ( 9 am) and one each evening ( 9 pm) except for the day of the experimental trial when both shots were taken together 2.5 h before the experimental trial. | Dietary Supplement: Placebo supplementtaion<br>* 2 × 70 mL/day shots of concentrate nitrate-depleted ( 0.08 mmol/day NO3-) beetroot juice. Two shots were supplemented for 5 days; one each morning ( 9 am) and one each evening ( 9 pm) except for the day of the experimental trial when both shots were taken together 2.5 h before the experimental trial.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma Nitrite Level | concentration [nmol] | Pre-exercise | 
| Motor Unit Activity | Duration (ms), area (uV.ms), firing rate (Hz) | Pre-exercise, post-exercise, recovery (45 s) |