Affiliations: [a] Human Performance Laboratory, UNESP, Rio Claro S.P.,
Brazil | [b] Department of Psychobiology and Sleep Institute,
Federal University of São Paulo, UNIFESP, Sao Paulo, Brazil
Note: [] Address for correspondence: B.S. Denadai, Laboratório de
Avaliação da Performance Humana, UNESP. Av. 24 A, 1515, Bela Vista,
Rio Claro, SP, Brasil, CEP – 13506-900. Tel.: +55 19 35264325; Fax: +55 19
35264321; E-mail: [email protected]
Abstract: The objective of this study was to examine the effects of high
intensity exhaustive running exercise on the muscular torque capacity of the
knee extensors for two types of contraction (concentric and eccentric) at
different angular velocities (60 and 180°/s) in
well-trained runners. Eleven male runners specialized in middle and
long-distance running volunteered to participate in this study. Initially each
subject performed, on different days, two familiarization sessions on an
isokinetic dynamometer and an incremental treadmill test to volitional
exhaustion to determine the velocity associated with the onset of blood lactate
accumulation (OBLA). The subjects then returned to the laboratory on two
occasions, separated by at least seven days, to perform maximal isokinetic knee
contractions at each of the velocities under eccentric (Ecc) and concentric
(Con) conditions. Conducted randomly, one test was performed after a
standardized warm-up period of 5 min at 50% VO_2max. The other test was
performed 15 min after continuous running at OBLA until volitional exhaustion.
Following this high intensity exercise there was a significant reduction of Con
at 60°/s and a significant reduction of Ecc at both
velocities. Percent strength losses after running exercise were significantly
different between contraction types only at 180°/s.
We can conclude that the reduction in isokinetic peak torque of the knee
extensors after a session of high intensity exhaustive running exercise at OBLA
depends on the contraction type and angular velocity.
