A low dose of 0.03 grams per kilogram of body weight per day of creatine (Phosphagen HP, EAS Inc.) for only 14 days resulted in 8% increases in peak power output and mean power output, compared to baseline values, while total work from the anaerobic tests increased 7% from baseline, report researchers from Appalachian State University and several universities in South America in the Journal of the International Society of Sports Nutrition.
"The dose used in this study appears to be the lowest effective dose of [creatine] seen in the current literature, even when [creatine] supplementation periods are as short as 14 days. These findings of beneficial effects of a low dose, short-term [creatine] supplementation are of importance for applied sport scientists, nutritionists, and strength and conditioning professionals by helping them to design better nutritional interventions aimed to improve muscle power output in elite youth soccer players," they wrote.
Study design
Study participants were members of the same youth competitive soccer team that have played in national and international championships at the time of the investigation, with a mean of 6.9 continuous years of soccer training and competition. Baseline measurements were taken by taking a 30 second Wingate Anaerobic Test to assess peak power output, mean power output, fatigue index, and total work—the same protocol repeated throughout the study.
All players were asked to maintain their normal dietary behaviors throughout the study. Compliance was assessed by return of empty supplement bags. Additionally, before the anaerobic test, participants were required to run on a motorized treadmill, with speed increased every five minutes until the point of voluntary exhaustion to measure fatigue index and oxygen uptake.
Results: Is a ‘loading phase’ for creatine still necessary?
The researchers wrote that, for the 19 players who completed the study, increases of peak power output (8% from baseline), mean power output (8% from baseline), and total work from the anaerobic tests (7% from baseline) for the creatine supplemented group were “similar of magnitude to previous studies using a ‘loading phase’ of about 20 to 25 g.d−1 of creatine”. Non-statistically significant increased in peak power output and mean power output were also reported in the placebo group.
Comparing results to other studies on creatine confirm that “the ‘loading phase’ of the creatine supplementation is effective but unnecessary to enhance muscle power output in humans.”
It should be noted that during the randomization phase, players in the placebo group had a mean weight of 74.2 kg, an 8 kg difference from the creatine group which the researchers argued was a significant difference.
But the difference between the placebo and creatine groups in mean power output and peak power output suggest that the dose used in this study, “appears to be the lowest effective dose of creatine seen in the current literature, even when creatine supplementation periods are as short as 14 days.”
Source: Journal of the International Society of Sports Nutrition
Published online ahead of print, doi: 10.1186/s12970-017-0162-2
Authors: A. Yanez-Silva, et al.