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

Objective: The objective of this study was to analyze the effects of prolonged continuous running performed at the intensity corresponding to the onset of blood lactate accumulation (OBLA), on the peak torque of the knee extensors, analyzed in relation to different types of contraction and movement velocities in active individuals. Method: Eight men (23.4 ± 2.1 years; 75.8 ± 8.7 kg; 171.1 ± 4.5 cm) participated in this study. First, the subjects performed an incremental test until volitional exhaustion to determine the velocity corresponding to OBLA. Then, the subjects returned to the laboratory on two occasions, separated by at least seven days, to perform five maximal isokinetic contractions of the knee extensors at two angular velocities (60 and 180°.s -1 ) under eccentric and concentric conditions. Eccentric peak torque (EPT) and Concentric peak torque (CPT) were measured at each velocity. One session was performed after a standardized warm-up period (5 min at 50% VO 2 max). The other session was performed after continuous running at OBLA until volitional exhaustion. These sessions were conducted in random order. Results: There was a significant reduction in CPT only at 60°.s -1 (259.0 ± 46.4 and 244.0 ± 41.4 N.m). However, the reduction in EPT was significant at 60°.s -1 (337.3 ± 43.2 and 321.7 ± 60.0 N.m) and 180°.s -1 (346.1 ± 38.0 and 319.7 ± 43.6 N.m). The relative strength losses after the running exercise were significant different between contraction types only at 180°.s -1 . Conclusion: We can conclude that, in active individuals, the reduction in peak torque after prolonged continuous running at OBLA may be dependent on the type of contraction and angular velocity.

This study analyzes the effects of prolonged running on knee extensor strength in active individuals.