Participants in this study will be randomly assigned to receive either creatine or placebo. Participants will be enrolled in the study for 9 months. Quantitative muscle testing will be done weekly for the first 3 weeks; participants will then be followed monthly for the next 4 months and bimonthly for the remainder of the 9-month study. The study will also monitor purposeful exercise to determine if this enhances the benefit of creatine usage on muscle strength. Pulmonary function testing will accompany the muscle testing to determine if creatine strengthens respiratory muscles, thereby enhancing pulmonary function.