EFFECT OF A NITRIC OXIDE PRE-WORKOUT SUPPLEMENT ON MUSCULAR ENDURANCE

Abstract

Introduction: Multi-ingredient dietary supplements have been developed to increase nitric oxide (NO) production, with the expectation of improving resistance training performance. Many of these supplements contain ingredients and/ or ingredient amounts that have yet to be studied for their synergy or efficacy in increasing NO production and thus, resistance training performance. Purpose of the study: A randomized crossover design was used to investigate the effect of a citrulline malate (CM) based non-stimulant nitric oxide pre-workout supplement (NOPWS) blend or placebo on Young Men’s Christian Association (YMCA) bench press performance. Applied Methodology: Thirty minutes were provided between NOPWS or placebo ingestion and YMCA bench press assessment. Pre/post heart rate was taken following each condition. Two- and one-way repeated measures ANOVAs (α = 0.05) were run to determine the effect of each condition on heart rate (HR) and the number of repetitions performed (respectively) during the bench press test. Achieved major results: There was a significant two-way interaction between the treatment and time for HR, F(1, 20) = 6.82, p = .017. Resting HR was significantly higher during the supplement session (M = 74.67, SE = 2.54 bpm) than during the placebo session (M = 69.14, SE = 2.31 bpm), F(1, 20) = 8.19, p = .010, ηp2 = .290. No significant difference was found between conditions for number of repetitions performed. Leads: A specific CM-containing NOPWS blend had no significant effect on a standardized assessment of upper body muscular endurance. Practical implications: These findings highlight the need for consideration of the minimum effective dosage and assimilation timing of each respective ingredient when developing or researching pre-workout supplement blends. Originality/Value: This is the first known research to study the effectiveness of this specific blend of ingredients on resistance training performance. Thus, this study provides necessary foundational knowledge for future research in this area.