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Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study.

Suzuki T, Morita M, Kobayashi Y, Kamimura A - J Int Soc Sports Nutr (2016)

Bottom Line: This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise.L-Citrulline supplementation significantly increased plasma L-arginine levels and reduced completion time by 1.5 % (p < 0.05) compared with placebo.Moreover, L-citrulline significantly improved subjective feelings of muscle fatigue and concentration immediately after exercise.

View Article: PubMed Central - PubMed

Affiliation: Healthcare Products Development Center, KYOWA HAKKO BIO CO., LTD., 2, Miyukigaoka, Tsukuba, Ibaraki 305-0841 Japan.

ABSTRACT

Background: Many human studies report that nitric oxide (NO) improves sport performance. This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise. L-Citrulline is an amino acid present in the body and is a potent endogenous precursor of L-arginine, which is a substrate for NO synthase. Here, we investigated the effect of oral L-citrulline supplementation on cycling time trial performance in humans.

Methods: A double-blind randomized placebo-controlled 2-way crossover study was employed. Twenty-two trained males consumed 2.4 g/day of L-citrulline or placebo orally for 7 days. On Day 8 they took 2.4 g of L-citrulline or placebo 1 h before a 4-km cycling time trial. Time taken to complete the 4 km cycle, along with power output/VO2 ratio (PO/VO2), plasma nitrite and nitrate (NOx) and amino acid levels, and visual analog scale (VAS) scores, was evaluated.

Results: L-Citrulline supplementation significantly increased plasma L-arginine levels and reduced completion time by 1.5 % (p < 0.05) compared with placebo. Moreover, L-citrulline significantly improved subjective feelings of muscle fatigue and concentration immediately after exercise.

Conclusions: Oral L-citrulline supplementation reduced the time take to complete a cycle ergometer exercise trial.

Trial registration: Current Controlled Trials UMIN000014278.

No MeSH data available.


Related in: MedlinePlus

Subjective feelings immediately after exercise. Values are means ± S.E.M. n = 22. * p < 0.05, indicating a significant difference from placebo
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Fig6: Subjective feelings immediately after exercise. Values are means ± S.E.M. n = 22. * p < 0.05, indicating a significant difference from placebo

Mentions: L-Citrulline significantly improved subjective feelings of muscle fatigue, and concentration, immediately after exercise (Fig. 6). A marked but not statistically significant improvement in ease of pedaling was observed with L-citrulline supplementation (p < 0.1).Fig. 6


Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study.

Suzuki T, Morita M, Kobayashi Y, Kamimura A - J Int Soc Sports Nutr (2016)

Subjective feelings immediately after exercise. Values are means ± S.E.M. n = 22. * p < 0.05, indicating a significant difference from placebo
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4759860&req=5

Fig6: Subjective feelings immediately after exercise. Values are means ± S.E.M. n = 22. * p < 0.05, indicating a significant difference from placebo
Mentions: L-Citrulline significantly improved subjective feelings of muscle fatigue, and concentration, immediately after exercise (Fig. 6). A marked but not statistically significant improvement in ease of pedaling was observed with L-citrulline supplementation (p < 0.1).Fig. 6

Bottom Line: This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise.L-Citrulline supplementation significantly increased plasma L-arginine levels and reduced completion time by 1.5 % (p < 0.05) compared with placebo.Moreover, L-citrulline significantly improved subjective feelings of muscle fatigue and concentration immediately after exercise.

View Article: PubMed Central - PubMed

Affiliation: Healthcare Products Development Center, KYOWA HAKKO BIO CO., LTD., 2, Miyukigaoka, Tsukuba, Ibaraki 305-0841 Japan.

ABSTRACT

Background: Many human studies report that nitric oxide (NO) improves sport performance. This is because NO is a potential modulator of blood flow, muscle energy metabolism, and mitochondrial respiration during exercise. L-Citrulline is an amino acid present in the body and is a potent endogenous precursor of L-arginine, which is a substrate for NO synthase. Here, we investigated the effect of oral L-citrulline supplementation on cycling time trial performance in humans.

Methods: A double-blind randomized placebo-controlled 2-way crossover study was employed. Twenty-two trained males consumed 2.4 g/day of L-citrulline or placebo orally for 7 days. On Day 8 they took 2.4 g of L-citrulline or placebo 1 h before a 4-km cycling time trial. Time taken to complete the 4 km cycle, along with power output/VO2 ratio (PO/VO2), plasma nitrite and nitrate (NOx) and amino acid levels, and visual analog scale (VAS) scores, was evaluated.

Results: L-Citrulline supplementation significantly increased plasma L-arginine levels and reduced completion time by 1.5 % (p < 0.05) compared with placebo. Moreover, L-citrulline significantly improved subjective feelings of muscle fatigue and concentration immediately after exercise.

Conclusions: Oral L-citrulline supplementation reduced the time take to complete a cycle ergometer exercise trial.

Trial registration: Current Controlled Trials UMIN000014278.

No MeSH data available.


Related in: MedlinePlus