Sixty male Wistar rats were randomly divided into six groups as sham ( n = 10 ) , ischemia-reperfusion ( n = 10 ) , exercise ( n = 10 ) , exercise plus ischemia-reperfusion ( n = 10 ) , ischemic preconditioning ( n = 10 ) , and ischemic preconditioning plus ischemia-reperfusion groups ( n = 10 ) .