The effects of pre versus post workout supplementation of creatine monohydrate on body composition and strength

Journal Title (Medline/Pubmed accepted abbreviation): J. Int. Soc. Sports Nutr
Year: 2013
Volume: 10
First Page: 36

Summary of background and research design:
Background: Creatine is one of the most popular supplements in the body building community due to its safety, availability, and efficacy. Creatine increases muscle size and strength in combination with resistance training. However, it is not known if creatine is more effective taken before or after exercise.

Research question: Does creatine supplementation have the greatest effects on strength and body composition when consumed before or after a workout?

Experimental Design: randomized, parallel groups

Subjects: recreational, amateur body builders, age 23.1 ± 2.9 y, n = 19

Treatments: 5 g of creatine monohydrate consumed:
  • 1) immediately before training, or
  • 2) immediately after training
On rest days, creatine was consumed at their convenience.

Protocol: The participants were first evaluated for height, weight, and body composition (BodPod®). One repetition maxima (1RM) were determined for bench press. They then completed a 4-week exercise regimen designed for body building; i.e. for muscle growth. The training was 5 days per week (Mon-Fri) with a total of 20 exercise sessions. Sessions were dictated by the study coordinators and alternated between 1) chest, shoulder, triceps, 2) hips, legs, and 3) back, biceps. Each workout was approximately 60 min long. A 24-hr dietary recall was provided on one random day per week for the 4 weeks. Body composition and 1RM were assessed again at the end of the 4 week program.

Summary of research findings:
  • Both groups tended to gain fat free mass (i.e. muscle) over the course of the study. The group that consumed creatine after the workout gained slightly more fat free mass compared to those who consumed creatine before the workout.
  • The "PRE" group lost 0.1 ± 2.0 kg body fat while those in the POST group lost 1.2 ± 1.6 kg (not statistically different).
  • 1RM for bench press increased 6.6 ± 8.2 kg for the PRE group and 7.7 ± 6.2 for the POST group (not statistically different).
  • A multivariate analysis concluded that creatine consumed after the workout may be more beneficial than creatine consumed before the workout.

Key practice applications: Consuming creatine after the workout may be more beneficial than consuming creatine before the workout in regard to increasing muscle mass and strength.

Limitations: The differences in groups did not reach statistical significance, meaning there is a probability greater than 1/20 that there was indeed no difference between groups. A larger sample size and/or a longer supplementation period may allow researchers to be more confident about the differences in timing of creatine consumption. Given that the study was only 4 weeks in duration, a longer period of training may lead to larger overall changes in fat-free mass and body fat, thus improving the power of the study to detect potential differences between pre- and post-exercise creatine administration.
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