Comparison of Responses of Fibrinolytic System to Types of Isokinetic Muscular Contractions in Men

The purpose of this study was to compare the responses of fibrinolytic system to different types of isokinetic muscular contractions in men. Ten healthy male (age 26.1±3.4 years) subjects performed three exercise protocols included Concentric/Concentric (C/C), Eccentric/ Eccentric (E/E) and Concentric/ Eccentric (C/E) contractions (Flexion and Extension) in knee joint for both legs by using a dynamometer system in three separated sessions. In each trial, subjects performed 4 sets of 10 repetitions of knee flexion and extension, at the speed of 60 degree per second. Blood Samples were taken before exercise, immediately and 30 minutes following exercise for measuring tissue plasminogen activator (t-PA) antigen, plasminogen activator inhibitor- 1 (PAI-1) antigen and D-dimer. t-PA antigen in response to three isokinetic contractions is significantly increased and recovery period decreased (P<0.05). Changes in t-PA antigen following C/C and C/E protocols were significantly (P<0.05) than E/E protocol. Regardless of the type of contractions, PAI-1 antigen levels in response to the isokinetic exercise is significantly increased, while, it significantly (p<0,05) decreased following recovery. However, responses to three protocols were not significantly different (P>0.05). D-dimer levels did not change in response to isokinetic exercise (P>0.05), and no significant differences among three protocols were detected. Based on the findings, it could be concluded that isokinetic contraction induces a rise in fibrinolytic system activity and that the C/C and C/E protocols results in more activation of fibrinolytic system compared to E/E protocol.