Data extraction
We extracted following data by a standardized electronic form (Microsoft
Office, Excel sheets): first author’s name, publication year and
country, design of study, gender and age of subjects, sample size,
intervention duration and creatine dose. Also, we extracted mean and SD
of plasma CK and LDH at baseline and after the intervention. Any
recorded standard errors of mean (SEM), were converted to SDs through
this formula: (SD = SEM × √n (n = number of individuals in intervention
or placebo groups). At last, in papers that reported information in
figures, extraction was carried out using GetData Graph Digitizer 2.24
(26).