Purpose: To determine the effects of 28 d of creatine supplementation during training on body composition, strength, sprint performance, and hematological profiles.
Methods: In a double-blind and randomized manner, 25 NCAA division IA football players were matched-paired and assigned to supplement their diet for 28 d during resistance/agility training (8 h·wk-1) with a Phosphagen HP (Experimental and Applied Sciences, Golden, CO) placebo (P) containing 99 g·d-1 of glucose, 3 g·d-1 of taurine, 1.1 g·d-1 of disodium phosphate, and 1.2 g·d-1 of potassium phosphate (P) or Phosphagen HP containing the P with 15.75 g·d-1 of HPCE pure creatine monohydrate (HP). Before and after supplementation, fasting blood samples were obtained; total body weight, total body water, and body composition were determined; subjects performed a maximal repetition test on the isotonic bench press, squat, and power clean; and subjects performed a cycle ergometer sprint test (12 × 6-s sprints with 30-s rest recovery).
Results: Hematological parameters remained within normal clinical limits for active individuals with no side effects reported. Total body weight significantly increased (P < 0.05) in the HP group (P 0.85 ± 2.2; HP 2.42 ± 1.4 kg) while no differences were observed in the percentage of total body water. DEXA scanned body mass (P 0.77 ± 1.8; HP 2.22± 1.5 kg) and fat/bone-free mass (P 1.33 ± 1.1; HP 2.43 ± 1.4 kg) were significantly increased in the HP group. Gains in bench press lifting volume (P -5 ± 134; HP 225 ± 246 kg), the sum of bench press, squat, and power clean lifting volume (P 1,105 ± 429; HP 1,558± 645 kg), and total work performed during the first five 6-s sprints was significantly greater in the HP group.
Conclusion: The addition of creatine to the glucose/taurine/electrolyte supplement promoted greater gains in fat/bone-free mass, isotonic lifting volume, and sprint performance during intense resistance/agility training.
Exercise & Sport Sciences Laboratory, Department of Human Movement Sciences & Education and the Department of Intercollegiate Athletics, The University of Memphis, Memphis, TN 38152; and Experimental& Applied Sciences, Inc., Golden, CO 80401
Submitted for publication February 1997.
Accepted for publication September 1997.