At the end of the race , there were no differences between the control group and the compression stockings group in serum myoglobin ( 568 347 ngmL ( -1 ) versus 573 270 ngmL ( -1 ) , respectively ; P = .97 ) and creatine kinase concentration ( 390 166 UL ( -1 ) versus 487 227 UL ( -1 ) , respectively ; P = .16 ) .