Data Analysis Statistical Analysis: Each subject will have PCr concentration collected at the following 2 time points: pre-statin (t1), and after 4-weeks of statin therapy (with ubiquinol or placebo) (t2). At each of these time points, a series of measurements of PCr concentration are collected. For each subject, we will estimate this parameter using maximum likelihood estimation method. Thus we will obtain the point estimate and standard error for the time constant parameter for each subject at each of the time points. We will compute the relative percent change from baseline to post-statin (ubiquinol vs. placebo) time points and a linear mixed effects model to obtain the estimate of the relative change from baseline and the relative change between the post-statin time point. The linear mixed effects model, with the compound symmetry structure for the variance-covariance matrix of the within-subject PCr relative changes from baseline takes into account the within-subject correlation. The estimation of the linear mixed-effects model will be done via restricted maximum likelihood method. The PCr recovery time constant will be calculated using a monoexponential fit of PCr versus time, beginning at exercise completion and will be compared between the groups.