DOI: http://dx.doi.org/10.18511/0103-1716/rbcm.v23n4p5-14
Purpose: The purpose of the present study was to assess muscle overload through changes in creatine kinase (CK) activity and serum concentration of ?-actin in soccer players in response of two months of pre-season physical training. Basic procedures: Ten professional athletes (26 ± 6 years of age) undergoing arduous training were evaluated. Serum CK activity and ?-actin serum concentration were determined at the beginning and end of two months of pre-season training. Effort intensity was determined throughout the training sessions by monitoring heart rate (HR). Serum CK activity was determined using the colorimetric method. Plasma ?-actin concentration was evaluated using ELISA and confirmed using the Western Blot method. Main Findings: Serum CK activity and ?-actin concentration were higher in the post-training period in comparison to the pre-training period (CK: PRE 65.5 ± 4.2 U/L, POST 435.7 ± 70.0 U/L, p=0.0004; ?-actin by Western Blot: PRE 42.9 ± 21.6 ?g/mL, POST 68.1 ± 19.1 ?g/mL, p=0.0004; by ELISA: PRE 70.63 ± 10.4 ?g/mL, POST 101.80 ± 17.3 ?g/mL, p=0.0125). Conclusions: The increase in CK activity and ?-actin concentration over two months of pre-season training of a soccer team indicates a significant muscle overload imposed by this training period. Thus, ?-actin and CK are factors for monitoring early muscle overload in the two-month physical preparation of a professional soccer team.