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Maxing Muscle Performance
Several studies show that in as few as five days, creatine and creatine-containing supplements augment muscle strength and endurance as well as speed.1,2 Other studies show creatine has no effect.3,4 In all studies, the only reported side effect is weight gain.
Recent data presented by Jeff Volek, Ph.D., and colleagues from Penn State University described increased muscle fiber and muscle area, as determined by CT scan, accompanied by increased strength and fat-free mass in young male weight lifters. This was achieved without changes in anabolic hormones.5
Using creatine for post-injury rehabilitation and recuperation was recently described by Peter Hespel, Ph.D., of the Catholic University in Louvain, Belgium. He administered creatine for 12 weeks (five days of loading at 20 g/day, then 5 g/day) to 11 subjects whose legs were placed in a cast for two weeks during a 10-week rehabilitation program, while 11 received placebo. Subjects taking creatine regained muscle fiber size and established new blood flow faster than those taking placebo.6
As for the weight-gain side effect of creatine, many debate whether water retention, muscle protein and/or glycogen is the cause, but no studies have determined the actual composition of the weight gained.
Using various methods under the leadership of Richard Kreider, Ph.D., and colleagues from the University of Memphis, we attributed creatine-associated weight gain to significant increases in muscle and bone mass with slight, concurrent decreases in fat mass. During these trials, the percentage of total body water did not increase.7,8 However, a recent crossover study by Tim Ziegenfuss, Ph.D., and colleagues at Kent St. University in Ohio found a significant increase in intracellular water volume after three days of creatine use.9 On a side note, we also analyzed data from five of our double-blind, placebo-controlled studies involving 164 subjects and found no greater incidence of cramps, muscle strains or pulls, or gastrointestinal distress compared with placebo.10
Athletes engaged in physical activities where speed, burst motions, power and strength are required may get the most robust response from creatine. These activities include baseball, basketball, field events, football, hockey, tennis, soccer, sprint cycling and running, and weight lifting. Based on current research, the best way to increase muscle creatine—a primary objective in creatine supplementation—is to take 5 g three to four times daily for two or three days with a beverage or meal that provides at least 75 g of simple carbohydrates. The maintenance dose is 5 g one or two times daily with or without a simple carbohydrate-rich beverage or meal.
—A.L.A.
References
1. Casey A, et al. Creatine supplementation favorable: affects performance and muscle metabolism during maximal intensity exercise in humans. Am J Physiol 1996;271:E31-7.
2. Smith JC, et al. Effect of oral creatine ingestion on rate-time relationship and time to exhaustion in high-intensity cycling. Eur J Appl Physiol 1998;77:360-5.
3. Cooke WH, et al. Effect of oral creatine supplementation on power output and fatigue during bicycle ergometry. J Appl Physiol 1995;78:670-3.
4. Febbraio MA, et al. Effect of creatine supplementation on intramuscular TCr, metabolism and performance during intermittent, supramaximal exercise in humans. Acta Physiol Scand 1995;155:387-95.
5. Kreider RB, et al. Effects of creatine supplementation during training on the incidence of muscle cramping, injuries and GI distress. Presented at the National Strength and Conditioning Association annual meeting, 1998 June 24-27, Nashville, Tenn; in press.
6. Hespel P. Presented at Creatine: From Basic Science to Clinical Application, Fondazione Giovanni Lorenzini; Milan, Italy. 1999 June 4.
7. Kreider RB, et al. Effects of ingesting supplements designed to promote lean tissue accretion on body composition during resistance training. Int J Sports Nutr 1996;6:234-46.
8. Kreider RB, et al. Effects of creatine supplementation on body composition, strength and sprint performance. Med Sci Sports Ex 1998;30:73-82.
9. Ziegenfuss TE, et al. Acute fluid volume changes in men during three days of creatine supplementation. J Exer Physiol online 1998;1:www.css.edu/users/tboone2/asep/jan13a.htm.
10. Volek JS, et al. Effects of long term creatine supplementation in strength training athletes. Presented at the National Strength and Conditioning Association annual meeting, 24-27 June 1998, Nashville, Tenn. Med Sci Sports Ex 1999; in press.
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