Effects of glycine-arginine-α-ketoisocaproic acid on muscular force and endurance

Objectives: To investigate the ergogenic properties of glycine-arginine-α-ketoisocaproic acid (GAKIC) during a bench and leg press exercise protocol. We hypothesized that GAKIC supplementation would improve muscular force and endurance. Methods: Eleven resistance trained males participated in a randomized, counterbalanced, crossover, double blind study. Participants were randomly assigned to placebo or GAKIC and performed one repetition maximum on the bench press and leg press. Also, total load volume was determined for both exercises. Blood lactate and glucose, and heart rate were determined pre- and post-exercise. One week later, participants ingested the other supplement and repeated same exercise protocol and same dependent measures were obtained.  Results: No differences were observed for one repetition maximum (placebo = 124.5±25.9 kg; GAKIC = 126.3±24.3 kg; p=0.37) or total load volume (placebo = 1683.1±409.4 kg; GAKIC = 1682.3±354.7 kg; p=0.99) during the bench press exercise protocol. GAKIC supplementation increased leg press one repetition maximum (placebo = 327.5±46.7 kg; GAKIC = 351.3±48.9 kg; p=0.02) and showed a trend in improving leg press total load volume (placebo = 4998.0±937.0 kg; GAKIC = 5410.7±847.4 kg; p=0.09). Heart rate and blood lactate were increased (p<0.01) post-exercise compare to pre-exercise for both bench press and leg press, but were not different between placebo and GAKIC. No changes were detected for blood glucose between pre- and post-exercise in either placebo or GAKIC. Conclusions: Collectively, these findings suggest that GAKIC results in a small muscular force, but not endurance, increase during lower body, but not upper body exercise.