BECQUE, M. D., J. D. LOCHMANN, and D. R. MELROSE. Effects of oral creatine supplementation on muscular strength and body composition. Med. Sci. Sports Exerc., Vol. 32, No. 3, pp. 654–658, 2000.
Purpose: 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.
Nutritional and biochemical supplements are continually introduced into sport and physical fitness. As the use of these nutritional supplements continues to increase, so does the need to investigate their effects on human performance.
Oral creatine supplementation increases the creatine and PCr content of human skeletal muscle (6,10,11,14,17,29,30). Creatine supplementation increases maximum intermittent bicycle and treadmill exercise performance during repeated bouts of exercise (1,4,6,8,15,21,27,28) but not in single maximum bouts (7,24,26) or endurance exercise (2).
A few studies have examined the effects of creatine supplementation during resistance exercise. The short-term (1 wk) effects of creatine supplementation without training include an increase in one repetition maximum (1RM) muscular strength (9), increased number of repetitions completed per set (9,31), and increased peak power during each set (31). Also, short-term supplementation increases isokinetic knee torques during repeated sets of knee extensions (12,13,29).
The effects of creatine supplementation and resistance training have been examined by four studies. Experienced male weight lifters (19,21) supplemented for 28 d. Noonan et al. (25) had experienced male weight lifters supplement for 8 wk. These studies showed increases in 3RM muscular strength (19), 1RM bench press (25), the amount of weight lifted in one set (21), and the number of repetitions completed in five sets (19). Neither maximum isometric strength (21) nor vertical jump height (25) increased. Vanderberghe et al. (30) resistance trained inexperienced females for 10 wk with creatine supplementation. 1RM muscular strength increased 20–25% for the leg press, leg extension, and squat exercise but not for the bench press and leg curl. Also, arm flexion torques during five sets of 30 repetitions were 11–25% greater after supplementation and training.
The physiological mechanisms linking creatine supplementation and increased exercise performance are largely unexplained. One possibility is an increase in body mass and fat-free mass. Several investigations found body mass increases after short-term creatine supplementation (1,2,9,31), and others found no change in body mass (8,29). Three resistance training studies (19,21,30) found increases in body mass and fat-free mass and one (25) found no change.
Despite an abundance of studies, only four studies (19,21,25,30) have examined the effects of creatine supplementation while strength training. Only two of these studies (25,30) reported changes in 1RM, a criterion measure of muscular strength. Moreover, one of the latter studies employed novice weight lifters (30) and the other football athletes (25). 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.