title: Creatine, arginine alpha-ketoglutarate, amino acids, and medium-chain triglycerides and endurance and performance.
abstract: Creatine (Cr) supplementation increases muscle mass, strength, and power. Arginine a-ketoglutarate (A-AKG) is a precursor for nitric oxide production and has the potential to improve blood flow and nutrient delivery (i.e., Cr) to muscles. This study compared a commercial dietary supplement of Cr, A-AKG, glutamine, taurine, branched-chain amino acids, and medium-chain triglycerides with Cr alone or placebo on exercise performance and body composition. Thirty-five men (approximately 23 yr) were randomized to Cr + A-AKG (0.1 g . kg(-1) . d(-1) Cr + 0.075 g . kg(-1) . d(-1)A-AKG, n = 12), Cr (0.1 g . kg(-1) . d(-1), n = 11), or placebo (1 g . kg(-1) . d(-1) sucrose, n = 12) for 10 d. Body composition, muscle endurance (bench press), and peak and average power (Wingate tests) were measured before and after supplementation. Bench-press repetitions over 3 sets increased with Cr + A-AKG (30.9 +/- 6.6 +/- 34.9 +/- 8.7 reps; p < .01) and Cr (27.6 +/- 5.9 +/- 31.0 +/- 7.6 reps; p < .01), with no change for placebo (26.8 +/- 5.0 +/- 27.1 +/- 6.3 reps). Peak power significantly increased in Cr + A-AKG (741 +/- 112 +/- 794 +/- 92 W; p < .01), with no changes in Cr (722 +/- 138 +/- 730 +/- 144 W) and placebo (696 +/- 63 +/- 705 +/- 77 W). There were no differences in average power between groups over time. Only the Cr-only group increased total body mass (79.9 +/- 13.0 +/- 81.1 +/- 13.8 kg; p < .01), with no significant changes in lean-tissue or fat mass. These results suggest that Cr alone and in combination with A-AKG improves upper body muscle endurance, and Cr + A-AKG supplementation improves peak power output on repeated Wingate tests.
authors.affiliation: College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Little
authors.forename: Scott C
authors.initials: SC
authors.lastname: Forbes
authors.forename: Darren G
authors.initials: DG
authors.lastname: Candow
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Cornish
authors.forename: Philip D
authors.initials: PD
authors.lastname: Chilibeck
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D000597:Amino Acids, Branched-Chain; D054874:Athletic Performance / Q000502:physiology; D003401:Creatine / Q000494:pharmacology*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D007656:Ketoglutaric Acids / Q000494:pharmacology*; D008297:Male; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D014280:Triglycerides / Q000097:blood*; D014891:Weight Lifting / Q000502:physiology; D055815:Young Adult
chemical_list: D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D007656:Ketoglutaric Acids; D014280:Triglycerides; D003401:Creatine