OBJECTIVE: To evaluate whether the serum beta-enolase level is a useful indicator of exercise-induced muscle damage in athletes. DESIGN: Blood samples were taken from 49 adult amateur marathon runners before and immediately after a marathon race, and the serum levels of beta-enolase and creatine phosphokinase were measured. SETTING: The Aoshima Taiheiyo Marathon 2000, Miyazaki, Japan, on a cloudy day in December with an ambient temperature of 18 degrees C. SUBJECTS: Forty-nine adult amateur marathon runners (42 men and 7 women) who regularly participated in runs. INTERVENTION: The intervention was a marathon run. MAIN OUTCOME MEASURES: Serum beta-enolase was measured using a sensitive sandwich enzyme-linked immunosorbent assay. Serum creatine phosphokinase was measured using a standard procedure. RESULTS: The mean beta-enolase concentration was 9.45 +/- 3.11 ng/mL before the race. It increased to 22.11 +/- 8.80 ng/mL after the race, representing a proportional increase of 1.57 +/- 1.46. The serum concentration of beta-enolase after the race was significantly higher than that before the race (P < 0.0001). Moreover, the serum beta-enolase level increased as much as the creatine phosphokinase level after the race, and strongly correlated with creatine phosphokinase (r = 0.828, P < 0.0001). The proportional increase of beta-enolase also correlated with that of creatine phosphokinase (r = 0.441, P < 0.005). CONCLUSIONS: Our data suggest that the absolute values of the serum beta-enolase are more appropriate to relate to muscle damage.
OBJECTIVE: To evaluate whether the serum beta-enolase level is a useful indicator of exercise-induced muscle damage in athletes. DESIGN: Blood samples were taken from 49 adult amateur marathon runners before and immediately after a marathon race, and the serum levels of beta-enolase and creatine phosphokinase were measured. SETTING: The Aoshima Taiheiyo Marathon 2000, Miyazaki, Japan, on a cloudy day in December with an ambient temperature of 18 degrees C. SUBJECTS: Forty-nine adult amateur marathon runners (42 men and 7 women) who regularly participated in runs. INTERVENTION: The intervention was a marathon run. MAIN OUTCOME MEASURES: Serum beta-enolase was measured using a sensitive sandwich enzyme-linked immunosorbent assay. Serum creatine phosphokinase was measured using a standard procedure. RESULTS: The mean beta-enolase concentration was 9.45 +/- 3.11 ng/mL before the race. It increased to 22.11 +/- 8.80 ng/mL after the race, representing a proportional increase of 1.57 +/- 1.46. The serum concentration of beta-enolase after the race was significantly higher than that before the race (P < 0.0001). Moreover, the serum beta-enolase level increased as much as the creatine phosphokinase level after the race, and strongly correlated with creatine phosphokinase (r = 0.828, P < 0.0001). The proportional increase of beta-enolase also correlated with that of creatine phosphokinase (r = 0.441, P < 0.005). CONCLUSIONS: Our data suggest that the absolute values of the serum beta-enolase are more appropriate to relate to muscle damage.