Break point of serum creatine kinase release after endurance exercise

Abstract

We investigated whether there is a break point of creatine kinase (CK) release after daily endurance exercise and whether CK response depends on individual physical characteristics. Fifteen healthy young men performed 90 min of bicycle exercise for 3 consecutive days. Body composition, properties of the quadriceps femoris muscle (QFM), and aerobic and anaerobic capacities were estimated before the test. Blood samples were obtained 22 times during the experimental period. Endurance exercise significantly elevated serum CK from 3 h after the first exercise session ( P < 0.05) and gradually increased thereafter. Subjects were classified into two groups according to their peak CK values: high responders (HR; >500 IU/l of CK) and low responders (LR; <300 IU/l of CK). Peak CK values during the experimental period correlated ( P < 0.01) with workload/cross-sectional area of the QFM ( r = 0.658), workload/volume of the QFM ( r = 0.648), and knee extensor strength/body mass ( r = −0.634); however, the HR and LR groups were separated in each variable. Thus the break point of CK release after endurance exercise under these conditions is 300–500 IU/l, two or three times higher than in the resting condition, and is associated with properties of the QFM.

Individual analysis of creatine kinase concentration in Brazilian elite soccer players

“…Due to the high variability found in CK concentration response to exercise in this as well as in other studies 15,21 , the CK Max of soccer players during a competition may not reach the proposed reference values, even knowing that the soccer players are being subjected to elevated muscle damage. Therefore, the use of a fixed CK threshold value may not be warranted.…”

“…In sports, the use of fixed reference values for CK concentration has been proposed for monitoring training load, these fixed reference values indicate a threefold for injury risk augmented 13,15 . The reference value of physiological parameters are important for interpretation of data 16 .…”

“…The reference value of physiological parameters are important for interpretation of data 16 . However, the use of fixed reference values for CK concentration as indicators of severe muscle damage is made difficult due to rather high inter and intra individual variability 6,7,15 . Another concurring factor might be the training status of the athletes 17 .…”

Comparison of different ways of expressing creatine kinase concentration of soccer players during a competitive season

“…29 During the pre-season, CK samples were collected on the 4 th , 10 th , and 15 th day. The average of these values corresponded to the time after pre-season (Post).…”

Verificação do dano muscular através da avaliação da concentração de creatina quinase em indivíduos não atletas após prova de ciclismo não competitivo

“…Além disso, também se observa elevação entre o segundo e sétimo dia após exercícios excêntricos, associando a elevação à lesão muscular [19,20]. Outro estudo com ciclistas não treinados mostrou aumento significativo de CK após 90 minutos de exercício, sendo que o aumento continuou ocorrendo até o terceiro dia de exercício [21].…”