Acute l-arginine alpha ketoglutarate supplementation fails to improve muscular performance in resistance trained and untrained men

Journal Title (Medline/Pubmed accepted abbreviation): J. Int. Soc. Sports Nutr. 
Year: 2012
Volume: 9
First page: 17
doi: 10.1186/1550-2783-9-17
Summary of Background and Research Design

Background: :  Nitric oxide (NO) is a natural molecule that increases blood flow and is thought to aid in sports performance by delivering nutrients to muscles and removing waste products at a faster rate.  It is produced from arginine by the enzyme nitric oxide synthase.  Additionally, alpha ketoglutarate is a molecule that is thought to augment ATP energy production by feeding the TCA/Krebs cycle.

Hypothesis: Acute l-arginine alpha ketoglutarate (AAKG) supplementation will increase the strength and muscular endurance of both trained and untrained men.

Subjects: Sixteen healthy males, age about 18-25 y, who had:
a) Participated in resistance training at least 2 times per week for the past 6 months (“trained”)
b) Not participated in resistance training for the last 3 years (“untrained”)

Experimental design: randomized, double-blinded, placebo-controlled, cross-over trial

Treatments : 3000 mg AAKG or a placebo (microcrystalline cellulose) dissolved in 300 mL water

Protocol : The participants reported to the laboratory three times.  During the first visit, they were assessed for height and weight and were familiarized with the exercise protocol.  During the second session, the participants consumed one of the beverages (AAKG or placebo).  Exactly 45 min later, the participants began the exercise protocol.  They warmed up for 5 min on a stationary bike, and then their 1 repetition maximum (1RM) was determined for bench press.  Sixty percent of their 1RM was calculated, and the participants completed as many repetitions as possible with that weight.  Total load volume (TLV) was calculated as the factor of the latter weight in kg times the number of repetitions.  After a lower body warm up, the participants completed the same protocol with a 45° plate loaded leg press.  Heart rate was measured at rest and then within 5 sec of completion of each of the exercises.  At least one week later, the participants returned to the lab and completed the protocol with the other beverage.

Summary of Research Findings
  • Trained subjects were stronger and exhibited a greater TLV than untrained subjects for the bench press (p < 0.05) but not the leg press (p > 0.05).
  • There were no significant differences in 1RM or TLV with AAKG vs. the placebo in either group for bench press or leg press (p > 0.05).
  • Heart rate was not different after exercise when comparing the treatments.

Key practice applications:

An acute dose of 3.0 g of AAKG had no effect on resistance exercise performance in either trained or untrained men.  Other studies have shown benefits with AAKG when it is consumed every day for at least 2 wks, though this study did not address long term ingestion of AAKG.

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