Acute Beetroot Juice Supplementation Has No Effect on Upper- and Lower-Body Maximal Isokinetic Strength and Muscular Endurance in International-Level Male Gymnasts

Ozcan Esen*, Joseph Fox, Raci Karayigit, Ian Walshe

*Corresponding author for this work

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Abstract

Nitrate (NO−3) has properties that can improve muscle function, leading to improvements in metabolic cost of exercise as well as enhance force production. Gymnastics is a whole-body sport, involving events that demand a high level of strength and fatigue resistance. However, the effect of NO−3 supplementation on both upper- and lower-body function in gymnasts is unknown. This study examined the effect of acute beetroot juice (BRJ) supplementation on isokinetic strength and endurance of the upper- and lower-body in highly trained international-level male gymnasts. In a double-blind, randomized crossover design, 10 international-level male gymnasts completed two acute supplementation periods, consuming either 2 × 70 ml NO−3-rich (∼12.8 mmol/L of NO−3) or NO−3-depleted (PLA) BRJ. Maximal strength of the upper-leg and upper-arm at 60°/s, 120°/s, 180°/s, and 300°/s, and muscular endurance (50 repeated isokinetic contractions at 180°/s) were assessed. Plasma NO−3 (BRJ: 663 ± 164 μM, PLA: 89 ± 48 μM) and nitrite (NO−2) concentrations (BRJ: 410 ± 137 nmol/L, PLA: 125 ± 36 nmol/L) were elevated following BRJ compared to PLA (both p < .001). Maximal strength of knee and elbow extensors and flexors did not differ between supplements (p > .05 for all velocities). Similarly, fatigue index of knee and elbow extension and flexion was not different between supplements (all p > .05). Acute BRJ supplementation, containing ∼12.8 mmol/L of NO−3, increased plasma NO−3 and NO−2 concentrations, but did not enhance isokinetic strength or fatigue resistance of either upper or lower extremities in international-level male gymnasts.
Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalInternational Journal of Sport Nutrition and Exercise Metabolism
Early online date18 Jan 2024
DOIs
Publication statusE-pub ahead of print - 18 Jan 2024

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