Acute responses of fibrinolytic factors to isotonic and isokinetic concentric contractions in healthy men

Present study was designed to investigate the effects of different isotonic and isokinetic concentric contractions and 1h recovery (1h-rec) period on fibrinolytic factors. Ten healthy male subjects (26.9 ±1.7 years) completed two isotonic and isokinetic exercise protocols at an intensity corresponding to 40% of maximal voluntary isometric torque at 70̊ (MVIT 70̊) on quadriceps using Biodex Systems which was followed by 1h-rec. Venous blood samples (6 ml) were obtained before, immediately after exercise and at the end of recovery and were analyzed for tissue plasminogen activator (t-PA),plasminogen activator inhibitor-1 (PAI-1), D-dimer and lactate concentration. All data were analyzed using repeated measures of ANOVA (2×3). Although both exercise trials irrespective of contraction type were followed by significant increases in t-PA and lactate (P<0.05), these increases were transient and returned to pre-exercise level at the end of 1h recovery. In addition, concentric isotonic contraction resulted in increases in both t-PA and lactate concentration compared to isokinetic contraction (P>0.05). Irrespective of contraction type, PAI-1 showed no significant changes after exercise but decreased significantly after 1h recovery (P>0.05). Not only, there was no significant differences between two type of contractions for PAI-1 (P>0.05), D-dimer, but also, responses of these variables to acute exercise and 1h recovery was not statistically significant(P>0.05). Based on thefindings of the present study,isotonic muscular contraction leads to more increases of t-PA and blood lactate levels in comprasion toisokinetic knee extension exercise, and that changes in PAI-1 and D-dimer are not related to muscle contraction type.