title: [Blood lactate in the steeplechase horse: triangular and rectangular series of steps during short duration races].
abstract: Five steeplechase race horses were observed during incremental and constant-load exercises with the aim of separating effects of work rate and time on blood lactate. Each independent exercise (an incremental and three constant load tests) was a sequence of three two-minute runs, separated by two one-minute rest intervals for jugular blood sampling. The following observations were made: 1. During constant load exercises, in the five horses, blood lactate stabilized below 4 mmol.l-1: lactatemia critical velocity (LVC) = 3.33 +/- 0.16 mmol.l-1. Nevertheless, VCL, critical lactate velocity inducing LVC, was not statistically different from VS4, velocity inducing a 4 mmol.l-1 blood lactate during incremental tests. Remaining reticent on the meaning of "lactate threshold" often attributed to VS4, an incremental exercise thus seemed pertinent for routine long-term surveys of endurance. 2. If delta L is the blood lactate increase within a single short run, delta L increases linearly with running velocity for an incremental test, allowing the calculation of a "null" velocity, the highest velocity for which there is no significant lactate increase. For independent runs, delta L increased exponentially with velocity, with noticeable differences between horses. This individual short-term functional adaptation variability could be considered in assessment and follow-up of race horse fitness.
mesh_terms: D000818:Animals; D006736:Horses / Q000097:blood*; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D012420:Running; D013997:Time Factors
chemical_list: D007773:Lactates; D019344:Lactic Acid
vernacular_title: Lactatémie chez le cheval de concours hippique: enchainements triangulaires et rectangulaires d'échelons de courses de courte durée.