Nitric oxide (NO) is a signaling molecule in humans that is known for its' vasodilative properties. L-arginine alpha-ketoglutarate is a natural product that has been shown to enhance the release of NO in the body. NO stimulators (NOS) are being marketed as being able to reduce fatigue associated with resistance training. PURPOSE: Therefore, the purpose of this study was to investigate L-arginine alpha-ketoglutarate on muscular strength and endurance during upper and lower body resistance exercise. METHODS: Twenty one active men (age = 20.04 ± 0.52) ingested L-arginine alpha-ketoglutarate (3-g) or a placebo (PL) 45 minutes prior to exercise in a randomized, double-blind crossover design. Participants refrained from supplement intake 72 hours and strenuous exercise 48 hours prior to the testing session, respectively. Initially, resting heart rate, blood pressure (BP) and lactate (LA) were obtained followed by one-repetition maximum (1-RM) testing on the barbell bench press and leg press. Upon determination of 1-RM, participants completed repetitions to failure at 60% of 1-RM. Heart rate, BP, LA, and rating of perceived exertion (RPE) were measured after the final repetition. RESULTS: Analysis revealed a significantly greater 1-RM bench press in the NOS condition compared to the PL (p = .04), however there was no difference between conditions for the 1-RM leg press. Additionally, no significant difference was seen between the PL and NOS treatments for upper or lower body muscular endurance. Measures of RPE, LA, BP, and heart rate were similar at the end of the muscular endurance set for both the upper and lower body exercise with NOS compared to PL. CONCLUSIONS: The results suggest that NOS may provide some ergogenic benefit during 1-RM on the bench press; however this ergogenic effect was not evident during maximal (1-RM) exertion on the leg press and muscular endurance exercises for the upper or lower body. PRACTICAL APPLICATION: In conclusion, NOS supplementation may provide some ergogenic benefits for upper body muscular strength (1-RM) on the bench press, yet this needs to be further explored.
Mississippi State University, Mississippi State, MS