BACKGROUND: Ischemic preconditioning (IPC) can effectively improve the ischemic resistance of skeletal muscle and reduce the necrotic areas during ischemia-reperfusion; However, the impacts of IPC on contractile function of skeletal muscle during ischemia-reperfusion is unclear.OBJECTIVE: To investigate the effect of IPC on contractile function of skeletal muscle during ischemia-reperfusion.DESIGN: A randomized controlled study by employing experimental animals as subjects.SETTING: Tongji Medical College, Huazhong University of Science and Technology and the 252 Hospital of Chinese PLA.MATERIALS: The experiment was completed in the 252 hospital of Chinese PLA. Totally 14 healthy SD rats were involved.METHODS: A rat right hindlimb ischemic model was utilized, 14 SD rats were randomly divided into control group and experimental group. Control group: sustained ischemia for 4 hours and reperfusion of 1 hour. Experimental group: ischemia for 5 minutes and reperfusion for 5 minutes, after 3 cycles, ischemia for 4 hours and reperfusion for 1 hour continuously of IPC.The isometric twitch contractile force of the right gastrocnemius muscle was measured as a parameter indicating the muscle functional status during is chemia reperfusion. The changes of creatine kinase (CK), malondialdehyde (MDA) in blood sample and the uptake of 99Tcm-methylene diphosphonate (99TcmMDP) in skeletal muscle were measured after 1 hour of reperfusion.MAIN OUTCOME MEASURES: The impacts of IPC on contractile force of gastroenemius and serous CK, MDA and the uptake of 99TcmMDP.RESULTS: The muscle contractile force in the experimental group after four hours of ischemia was (14.32 ± 5.05) g or (25.71 ± 7.58) g after one-hour reperfusion, which was significantly higher than 0 g or (4. 73 ± 2.05) g of control group(P ＜0. 05). The serous levelsofCK [(104.85 ±9. 84) nkat/L], MDA [ (3 988.60 ± 455.92) nmol/L] and the uptake of 99TcmMDP [ (56.0± 8.1 ) mBq/g per minute] were significantly lower in the experimental group than control group [CK(136.36 ± 14.50) nkat/L, MDA (6 542.90±536.72)nmol/L, and 99TcmMDP (97.3 ±5.8) mBq/g per minute, P＜0.05, P ＜0.01].CONCLUSION: IPC can effectively ameliorate the contractile force of skeletal muscle and reduce the necrotic degree of skeletal muscle. Therefore, IPC has a protective effect on the contractile force of ischemic skeletal muscle.