Background and objective: Peak torque, as measured by the gold standard
method of isokinetic dynamometry, is affected by consumed of dietary nitrate
(NO) in the form of beetroot juice (BRJ). The increasing strength
performance effect of BRJ has also started to arouse interest in combat sports.
This study aims to investigate the effects of acute dietary nitrate
supplementation on lower and upper body isokinetic strength of trained
Materials and methods: The study is a double-blind, randomized,
crossover design in which eight trained male Greco-Roman wrestlers (21.87
2.3 years; height 176.87 cm 4.1 cm; body weight 76.75 kg 5.4 kg)
consumed beetroot juice (140 mL) or placebo (140 mL, cherry juice with lemon
juice) 150 min before performing isokinetic strength. Participants performed knee
extensors and flexors and shoulder internal and external rotator isokinetic
strength test (in the dominant limbs) concentrically at 60 with by
Cybex device (Cybex NORM®, Humac, CA, USA). The same trial
procedure was repeated with the other supplement (BRJ or Placebo) in a second
testing session five days later. BRJ and Placebo trials’ isokinetic strength
values were compared with parametric testing (paired sample T-test).
Results: Although there was a significant difference in peak torque of
shoulder internal and external rotator values in favor of BRJ (P
0.05), there was no significant difference in the knee strength test.
Additionally, all average isokinetic strength values were significantly increased
in the BRJ trial (P 0.05).
Conclusions: These results suggest that BRJ can be used as an ergogenic
effect for improving strength values in Greco-Roman wrestling.