Changes in strength and functional ability in older adults in response to creatine supplementation and resistance training
Creators: name: Dolcetti, Joseph Cleary
Publisher: name: University of British Columbia
Year: 2009

description: The purpose of this study was to investigate the effects of creatine monohydrate (Cr.H2O) supplementation in conjunction with six weeks of resistance training on the strength and functional abilities of older adults. Recently, several studies have looked at the effectiveness of Cr.H2O supplementation in enhancing performance and recovery during several types of high-intensity short-term (HI-ST) activity. However, few studies have examined the effects of supplementation in conjunction with resistance training and none have used older subjects. Fatigue during HI-ST activities such as a resistance training is largely the result of the inability of phosphocreatine (PCr) hydrolysis to maintain a high adenosine triphosphate (ATP): adenosine diphosphate (ADP) ratio, due to depletion of the limited PCr stores in the muscle. Oral Cr.H2O supplementation can significantly increase both muscle and whole body creatine stores. Cr.H2O supplementation may enhance performance in conjunction with resistance training as a result of (1) an increase in the initial muscle PCr pool (2) enhanced PCr resynthesis during recovery and possibly (3) through an increase in protein synthesis. In older adults the age-associated loss of muscle strength, which progresses rapidly after the age of 50, is related to an individual's ability to maintain an independent and healthy lifestyle. In the present study 53 males and females aged 50 - 75 years of age volunteered to participate. The study involved a double blind, repeated measures design, in which subjects self-administered four, 5 gram servings for one week followed by five weeks of one 5 gram serving per day of either Cr.H2O (Cr group, n=27) or a placebo (P group, n=26). During the six week supplementation period all subjects participated in a three-session per week whole body resistance training program. Measurements for body weight (WT) and chest press repetitions to failure (REPS) using a pre-established 10 RM weight were taken prior to (T1) after one week (T2) and following (T3) the six week training/supplementation period. T1 and T3 measurements were also taken for grip strength (GRIP), and the constructs FUNCTION (combining the chair rise and medicine ball lift functional tests) and STRENGTH (combining 10 RM tests for chest press, seated row, leg extension and leg curl). ANOVA analyses revealed all subjects performed considerably more repetitions for REPS at T2 AND T3 but no significant differences were seen between the Cr and P groups for this variable at T2 or T3 (α=0.05). MANOVA analyses of the measurements GRIP, STRENGTH, and FUNCTION showed subjects improved significantly on all three of these measures as a result of training but these improvements were not significantly different between treatment groups. However, post-hoc analyses revealed males and females in the Cr group varied in their response to creatine supplementation when compared independently to their Pl group counterparts. The Cr males demonstrated a 31% increase in STRENGTH compared to a 21% improvement experienced by the Pl males. This approximate 10% greater level of improvement for the Cr males was significantly different from the Pl males (p=0.009). The females in the Cr and Pl groups experienced a 32% and 30% improvement in STRENGTH, respectively. To the author's knowledge this study represents the first time the effects of creatine supplementation have been studied in an older adult population and the first to show a significant difference between males and females in response to supplementation combined with resistance training.