Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow

This study determined the effects of 28 days of oral creatine ingestion (days 1 to 5 = 20g/d; [5 g 4 times daily]: days 6 to 28 = 10 g/d; [5 g twice daily]) alone and with resistance training (5 hours/week) on resting metabolic rate (RMR), body composition, muscular strength (1RM), and limb blood flow (LBF). Using a double-blind, placebo-controlled design, 30 healthy male volunteers (21 +/-3 years; 18 to 30 years) were randomly assigned to 1 of 3 groups; pure creatine monohydrate alone (Cr; n=10), creatine plus resistance training (Cr-RT; n=10), or placebo plus resistance training (P-RT; n=10). Body composition (DEXA, Lunar DPX-IQ), body mass, bench, and leg press 1RM (isotonic), RMR (indirect calorimetry; ventilated hood), and forearm and calf LBF (venous occlusive plethysmography) were obtained on all 30 subjects on 3 occasions beginning at approximately 6:00 AM following an overnight fast and 24 hours removed from the last training session; baseline (day 0), and 7 days and 29 days following the interventions. No differences existed among groups at baseline for any of the variables measured. Following the 28-day interventions, body mass (Cr, 73.9 +/- 11.5 v 75.6 +/- 12.5 kg; Cr-RT, 78.8 +/-6.7 v 80.8 +/-6.8 kg; P<.01) and total body water (Cr, 40.4<plus/minus>6.8 v 42.6 +/-7.2 L, 5.5%; Cr-RT, 40.6 +/-2.4 v 42.3 +/-2.2 L, 4.3%; P<.01) increased significantly in Cr and Cr-RT, but remained unchanged in P-RT, whereas, fat-free mass (FFM) increased significantly in Cr-RT (63<plus/minus>2.8 v 64.7 +/-3.6 kg; P<.01) and showed a tendency to increase in Cr (58.1<plus/minus>8.1 v 59 +/-8.8 kg; P=.07). Following the 28-day period, all groups significantly increased (P<.01) bench (Cr, 77.3<plus/minus>4 v 83.2 +/-3.6 kg; Cr-RT, 76.8 +/-4.5 v 90.5 +/-4.5 kg; P-RT, 76.0 +/-3.4 v 85.5 +/-3.2 kg), and leg press (Cr, 205.5 +/- 14.5 v 238.6 +/- 13.2 kg; Cr-RT, 167.7 +/- 13.2 v 238.6 +/- 17.3 kg; P-RT, 200.5 +/-9.5 v 255 +/- 13.2 kg) 1RM muscular strength. However, Cr-RT improved significantly more (P<.05) on the leg press IRM than Cr and P-RT and the bench press 1RM than Cr (P<.01). Calf (30%) and forearm (38%) LBF increased significantly (P<.05) in the Cr-RT, but remained unchanged in the Cr and P-RT groups following the supplementation period. RMR expressed on an absolute basis was increased in the Cr (1,860.1<plus/minus>164.9 v 1,907 +/- 173.4 kcal/d, 2.5%; P<.05) and Cr-RT (1,971.4<plus/minus>171.8 v 2,085.7 +/- 183.6 kcal/d, 5%; P<.05), but remained unchanged from baseline in P-RT. Total cholesterol decreased significantly in Cr-RT (-9.9%; 172<plus/minus>27 v 155 +/- 26 mg/dL; P<.01) compared with Cr (174<plus/minus>46 v 178 +/- 43 mg/dL) and P-RT (162 +/- 32 v 161 +/- 36 mg/dL) following the 28-day intervention. These findings suggest that the addition of creatine supplementation to resistance training significantly increases total and fat-free body mass, muscular strength, peripheral blood flow, and resting energy expenditure and improves blood cholesterol. Copyright (C) 2001 by WB. Saunders Company.