Long-term creatine supplementation improves muscular performance during resistance training in older women


Journal Title (Medline/Pubmed accepted abbreviation): Eur. J. Appl. Physiol.
Year: 2013
Volume: 113
Page numbers: 987-996
doi (if applicable): 10.1007/s00421-012-2514-6

Summary of background and research design:
Background:  Aging naturally leads to a decline in muscle size and strength, which can impair people’s ability to do normal, day-to-day physical tasks such as standing up from a chair or bed.  Resistance training undoubtedly increases muscle strength and functional ability.  Creatine is very effective at increasing muscle strength in combination with resistance training in younger populations and increasing evidence has recently shown benefits in older populations as well.

Hypothesis:  In combination with resistance training, creatine supplementation will accelerate gains in muscle strength with improvements in functional performance in older women.

Experimental Design:  randomized, double-blind, placebo-controlled, parallel groups, repeated measures

Subjects:  healthy, non-athletic women (n = 18), age 64.9 ± 5.0 y

Treatments: 
  1. Creatine (Phosphagen® by EAS®), 5 g/day
  2. Placebo- maltodextrin- 5 g/day
Supplements were dissolved in the post-workout carbohydrate beverage and consumed immediately after the workout.

Protocol: 
After becoming comfortable with the exercises and functional performance tasks, the participants partook in two 12 week programs that involved resistance training 3 times per week.  This first phase was to accustom them to resistance training and eliminate a learning bias.  Subsequently, the participants were randomized and baseline measures were acquired.  Participants were matched for age, body mass, and 1 repetition maximum (1RM).  They completed the second 12 week program (3 times per week) during which they consumed one of the treatments.  The exercise program worked upper body, lower body, and core muscles.  To test the effects of creatine, 1RM (bench press, bicep curl, knee extension), functional tests (30 sec chair stand, arm curl, and “getting up from lying on the floor”) and body composition [dual x-ray absorptiometry (DEXA)] were assessed before and after the second 12 week phase.
Summary of research findings:
  • 100% of the participants completed the study.  None reported adverse side effects from supplementation.
  • Participants in both groups increased their 1RM for bench press, knee extension, and bicep curl.  The ones taking creatine displayed larger gains (p < 0.05 for all exercises).
  • Training volume increased to a 2-fold greater extent with creatine than with the placebo during the 12 week program.
  • All functional assessments improved with exercise including number of repetitions of sitting/standing from a chair in 30 sec, number of repetitions for arm curl (5 lbs.) in 30 sec, and time it took to stand from lying on the floor.  Those that took creatine exhibited greater improvements.
  • Those that took creatine gained significantly more muscle mass than those who took the placebo.  Body mass, fat mass, nor percent body fat changed over the course of the program for either group.
Key practice applications:  Creatine increased gains in strength during a 12-week resistance training program in older women.  Importantly, creatine supplementation also accelerated the rate at which the women improved on everyday physical tasks such as standing from a chair or lying down.  These results imply that creatine supplementation with an exercise program could prolong or more quickly recover independence in old age.
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