Effects of prolonged running performed at the intensity corresponding to the onset of blood lactate accumulation, on maximum isokinetic strength in active non-athletic individuals

Abstract

Objective: The objective of this study was to analyze the effects ofprolonged continuous running performed at the intensity corresponding tothe onset of blood lactate accumulation (OBLA), oil the peak torque ofthe knee extensors, analyzed in relation to different types ofcontraction and movement velocities in active individuals. Method: Eightmen (23.4 +/- 2.1 years; 75.8 +/- 8.7 kg; 171.1 +/- 4.5 cm) participatedin this study. First, the Subjects performed all incremental test untilvolitional exhaustion to determine the velocity corresponding to OBLA.Then, the Subjects returned to the laboratory oil two occasions,separated by at least seven days, to perform five maximal isokineticcontractions of the knee extensors at two angular velocities (60 and 180degrees.s(-1)) under eccentric and concentric conditions. Eccentric peaktorque (EPT) and Concentric peak torque (CPT) were measured at eachvelocity. One session was performed after a standardized warm-up period(5 min at 50% VO(2)max). The other session was performed afterContinuous running at OBLA until volitional exhaustion. These sessionswere conducted in random order. Results: There was a significantreduction in CPT only at 60 degrees.s(-1) (259.0 +/- 46.4 and 244.0 +/-41.4 N.m). However, the reduction in EPT was significant at 60degrees.s(-1) (337.3 +/- 43.2 and 321.7 +/- 60.0 N.m) and 180degrees.s(-1) (346.1 +/- 38.0 and 319.7 +/- 43.6 N.m). The relativestrength losses after the running exercise were significant differentbetween contraction types only at 180 degrees.s(-1). Conclusion: We callConclude that, in active individuals, the reduction in peak torque afterprolonged continuous running at OBLA may be dependent oil the type ofcontraction and angular velocity.