RESUMO
OBJECTIVE: To analyze the relationship between the blood biochemical indexes and the local muscle fatigue of operators with local muscle fatigue caused by moderate-load repetitive manual lifting. METHODS: Five healthy male volunteers were selected as the research subjects. They repeatedly performed simulated manual lifting operation for four periods(T1-T4), 10 minutes per period. Each period was suspended for 3 minutes to be accessed for the rating of perceived exertion(RPE) score of local muscle. Meanwhile, their venous blood was collected to be detected for serum calcium ion, creatine kinase, cartilage oligomeric matrix protein(COMP), ammonia, lactic acid, lactate dehydrogenase(LDH), C-reactive protein(CRP), and collagen type Ⅱ C terminal telopeptide(CTX-Ⅱ). RESULTS: The RPE score and serum creatine kinase level of the subjects increased with the increasing of lifting time(P<0.05). Serum calcium ion levels in time periods T2, T3 and T4 were higher than that in T1(P<0.05). Serum COMP levels in T3 and T4 were higher than that in T1(P<0.05). The levels of ammonia,lactic acid, LDH, CRP and CTX-Ⅱ in each time period showed no statistical significance(P>0.05). Serum creatine kinase, calcium ion and LDH levels were positively correlated with RPE score(correlation coefficient were 0.840, 0.512, 0.741, respectively, P<0.01). CONCLUSION: Serum creatine kinase is a sensitive, effective and objective index reflecting muscle fatigue, which is suitable for evaluating the fatigue process of moderate-load repetitive activities. Serum calcium ion has a good correlation with muscle fatigue, and serum COMP can reflect muscle fatigue to some extent.