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To investigate cardioprotective effect of exercise preconditioning in military personnel with different training intensities, and look for appropriate training intensity and process.
40 military new recruits were randomly divided into two groups: normal intensity training goup(NIT group,n=20) with 5 km armed cross-country training twice a day, and low intensity training group(LIT group,n=20) with 5 km armed cross-country training once a day, two groups trained for 1 month. Before training, the new recruits were told how to train scientifically. Serum samples were collected and cardiac troponin I(cTnI) CK-MB and CK levels were observed before training, after 1week training and 4 weeks training.
Result 1. In NIT goup, the cTnI levels increases after 1 week training, but there isn't significant difference(p>0.05); the cTnI levels decreases after 4 weeks training(p<0.05). And in LIT group, there were no significant differences during the training on the cTnI levels(p>0.05). In NIT goup, the CK-MB/CK levels increase significantly after 1 week training and 4 weeks training (p<0.05); there were no significant differences between 1 week training and 4 weeks training(p>0.05). In LIT group, there were no significant differences during the training on the the CK-MB/CK levels(p>0.05). 2. There were no significant differences on both cTnI levels and CK-MB/CK levels between the NIT group and LIT group before training(p>0.05); there were significant difference after 1 week training (p<0.05); and there were no significant difference after 4 weeks training (p>0.05).
High intensities training in new recuits was prone to cardiomyocyte injury, and different intensities was probably correlated with degrees of cardiomyocyte injury. This phenomenon could be related to the training-induced cardiomyocyte injury and exercise preconditioning.