Abstract: Objective:To determine whether exercise preconditioning(EP) is capable of protecting myocardium from exhaustive exercise and view the change of εPKC expression during exercise preconditioning.Methods:SD rats were divided into control group(C),EE group,LEP group,LEP+EE group.After establishing of EP animal model,exhaustive exercise on treadmill for inducing myocardial injury.Then the level of cTnI was detected by chemiluminescent immunoassay.Western blotting method was used to detect changes of εPKC,immunohistochemistry method was used to observe expressions of εPKC.Results:As compared with the group C,the cTnI level in serum increased significantly,εPKC significantly increased and εPKC translocated from the soluble to the intercalated disk in group EE.While compared with the group C,there was no significant difference in the cTnI level in group LEP,but εPKC significantly increased and the εPKC translocated from the soluble to the intercalated disk.As compared with the group EE,the cTnI level in serum decreased significantly in group LEP+EE,there was no significant difference in εPKC level and there was no expression at intercalated disk.Conclusion:Exercise preconditioning induced-late myocardial protection against exhaustive exercise injury and εPKC participated in late cardioprotection induced by exercise preconditioning.