| Abstrakt: |
The speed producing the maximal lactate steady state (maxLASS) is supposed to be the optimal speed to condition for endurance. The maxLASS was defined as the maximal speed at which the blood lactate concentration ([LA]) between the 5th and the 25th mill of continuous exercise did not increase by more than 1 mmol⁄L. According to the aerobic–anaerobic lactate threshold concept determined in humans, maxLASS corresponds to v4 [speed in a standardized exercise test (SET) shown to produce an [LA] of 4 mmol⁄L; generalized to v, for the speed producing an [LA] of i mmol⁄L]. Four Thoroughbreds were submitted to a treadmill–based SET to determine their blood lactate–running speed (BLRS) relationship and calculate the individual v1.5, v2, v2.5, v3, and v4 values (velocities run under defined conditions inducing 1.5, 2, 2.5, 3, and 4 mmol⁄L of blood LA). Afterward, horses ran on the treadmill for 40 mill at their v1.5, v2, and v2.5 every 3 d. Another 14 horses were submitted to SET in the field to determine their BLRS relationships and to calculate their v2. The day after the SET, these horses ran once between 15 and 30 mm at their v2. In the horses that ran on the treadmill, maxLASS only occurred when running at their v1.5. Blood [LA] did not increase by more than 1 mmol⁄L between the 10th mm and the end of exercise for all the horses that ran in the field at their v2 These data indicate that maxLASS of horses is not greater than v2 and therefore less than in running humans. [ABSTRACT FROM AUTHOR] |
