Journal Title (Medline/Pubmed accepted abbreviation): Nutrition
Volume: Published ahead of print
Hypothesis:Very low-dose creatine ingestion, when ingested over a sufficient period of time, will improve body composition, muscle function, and body creatine retention.
Subjects:20 non-vegetarian subjects (12 men, 8 women) participated in the study. In the creatine group, mean age was 21.0 ± 2.3 years, mean height was 171.4 ± 10.1 cm, mean body mass was 74.3 ± 14.0 kg, and mean body mass index (BMI) was 25.1 ± 3.1 kg/m2. The placebo group had similar subject characteristics with a mean age of 20.5 ± 2.3 years, mean height of 171.8 ± 6.9 cm, mean body mass of 76.5 ± 7.1 kg, and mean BMI of 25.9 ± 2.3 kg/m2.
Experimental design:Randomized, double-blind, placebo-controlled
Treatments and protocol:Visits 1 and 2 occurred 7 days apart prior to supplementation and were used to establish reliable baseline measurements. Subjects completed anthropometric/body composition, muscle strength, and muscle fatigue tests, and provided a blood sample. Body mass and body composition were assessed with the BC-418 8-contact electrode bioimpedance analyzer. Maximal strength and muscle fatigue were assessed in random order with a 5-minute rest between tests. Muscle strength was assessed with a 3?repetition maximal (3-RM) concentric knee extension test at 180 degrees/second and muscle fatigue was assessed with 5 sets of 30 concentric knee extensions at 180 degrees/second with a 60-second rest between sets. Following Visit 2, subjects ingested 0.03 g creatine or placebo per kg of body weight per day for 6 weeks (range, 1.7 to 2.9 g/day). Subjects were instructed to ingest the supplements with food to enhance body creatine retention. After the supplementation phase, subjects repeated the anthropometric/body composition, muscle strength, and muscle fatigue tests, and provided a blood sample. Testing was conducted at the same time of day for all 3 visits (± 1 hour), and subjects reported to the laboratory in a postprandial state. Based on analysis of variance (ANOVA), the level of statistical analysis was set a priori at P ≤ .05.