The purpose of this investigation was to examine the effects of 6 wk of oral creatine supplementation during a periodized program of arm flexor strength training on arm flexor 1RM, upper arm muscle area, and body composition.Methods:
Twenty-three male volunteers with at least 1 yr of weight training experience were assigned in a double blind fashion to two groups (Cr, N = 10; Placebo, N = 13) with no significant mean pretest one repetition maximum (1RM) differences in arm flexor strength. Cr ingested 5 g of creatine monohydrate in a flavored, sucrose drink four times per day for 5 d. After 5 d, supplementation was reduced to 2 g·d−1. Placebo ingested a flavored, sucrose drink. Both drinks were 500 mL and made with 32 g of sucrose. 1RM strength of the arm flexors, body composition, and anthropometric upper arm muscle area (UAMA) were measured before and after a 6-wk resistance training program. Subjects trained twice per week with training loads that began at 6RM and progressed to 2RM.Results:
1RM for Cr increased (P < 0.01) from (mean ± SD) 42.8 ± 17.7 kg to 54.7 ± 14.1 kg, while 1RM for Placebo increased (P < 0.01) from 42.5 ± 15.9 kg to 49.3 ± 15.7 kg. At post-test 1RM was significantly (P < 0.01) greater for Cr than for Placebo. Body mass for Cr increased (P < 0.01) from 86.7 ± 14.7 kg to 88.7 ± 13.8 kg. Fat-free mass for Cr increased (P < 0.01) from 71.2 ± 10.0 kg to 72.8 ± 10.1 kg. No changes in body mass or fat-free mass were found for Placebo. There were no changes in fat mass and percent body fat for either group. UAMA increased (P < 0.01) 7.9 cm2 for Cr and did not change for Placebo.Conclusion:
Creatine supplementation during arm flexor strength training lead to greater increases in arm flexor muscular strength, upper arm muscle area, and fat-free mass than strength training alone.