2006 Creatine and Exercise Study: REPOST

[Guest guest]

(Note to all: this is the most recent published abstract about

creatine and exercise - I posted this to the group right when it came

out, so it is in our archives, but since Barb mentioned the 2004

study, I wanted to make sure everyone has the most recent study. Read

below - especially note the last paragraph) Dr. Chetlin and

colleagues are continuing their work on this subject.

~ Gretchen

Muscle Nerve. 2006 Jul 31

Effects of exercise and creatine on myosin heavy chain isoform

composition in patients with Charcot-Marie-Tooth disease.

CA, Chetlin RD, Gutmann L, Yeater RA, Alway SE.

Laboratory of Muscle Biology and Sarcopenia, Division of Exercise

Physiology, West Virginia University School of Medicine, P.O. Box

9227, town, West Virginia 26506, USA.

It is not known whether myosin heavy chain (MHC) content changes in

response to exercise training or creatine supplementation in subjects

with Charcot-Marie-Tooth disease (CMT). Based on previous data, we

hypothesized that resistance exercise and creatine would increase the

percentage of type I MHC composition in the vastus lateralis muscle

and that myosin isoform changes would correlate with improved chair

rise-time in CMT subjects.

To test this hypothesis, 18 CMT subjects were randomly assigned to

either a placebo or creatine group. All subjects performed a 12-week,

home-based, moderate-intensity resistance training program. Chair

rise-time was measured before and after the training program. Muscle

biopsies were obtained from the vastus lateralis before and after the

12-week program. Gel electrophoresis showed a significant decrease (

approximately 30%) in MHC type I in CMT subjects given creatine

supplementation when compared with placebo.

There was a nonsignificant increase in both MHC type IIa (

approximately 23%) and MHC type IIx ( approximately 7%) in CMT

subjects given creatine. Reduced MHC type I content and increased MHC

type IIa content correlated with faster chair rise-times (i.e.,

improved muscle performance). The training-induced change in MHC IIa

content was inversely correlated with chair rise-time in CMT subjects

given creatine.

When the two subject groups were combined, there was a linear,

negative relationship between the change in MHC type IIa content and

chair rise-time after training and a positive relationship between

the training-induced change in MHC type I content and chair rise-

time. These data suggest that improved function (chair rise-time) was

associated with a lower level of MHC type I and increased MHC type

IIa composition.

Furthermore, the data are consistent with the hypothesis that

creatine supplementation alters MHC composition in CMT patients

undergoing resistance training and that MHC changes associated with

creatine supplementation can improve muscle function.