Maximal lactate steady state during exercise in blood of horses1

Abstract

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 min 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 v(4) [speed in a standardized exercise test (SET) shown to produce an [LA] of 4 mmol/L; generalized to v(i) 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 v(1.5), v(2), v(2.5), v(3), and v(4) 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 min at their v(1.5), v(2), and v(2.5) every 3 d. Another 14 horses were submitted to SET in the field to determine their BLRS relationships and to calculate their v(2). The day after the SET, these horses ran once between 15 and 30 min at their v(2). In the horses that ran on the treadmill, maxLASS only occurred when running at their v(1.5). Blood [LA] did not increase by more than 1 mmol/L between the 10th min and the end of exercise for all the horses that ran in the field at their v(2.) These data indicate that maxLASS of horses is not greater than v(2) and therefore less than in running humans.

Comparison of maximal lactate steady state with V2, V4, individual anaerobic threshold and lactate minimum speed in horses

“…V 2 and V 4 : There are various studies that have investigated the metabolic responses of athletes during constant exercise at threshold intensities in humans (Faude et al, 2009) and horses (Lindner, 2010). In our study, V 2 and V 4 values were always above the V MLSS values, and in addition, the animals were not capable of sustaining those velocities in the MLSS test without an increment of 1 mmol.L -1 .…”

“…The assessment of this threshold, by means of the quantification of some metabolic variables, particularly lactacidemia, has also been utilized for athletic horses (Bas et al, 2000;Rogers et al, 2007;Lindner et al, 2009;Lindner, 2010). There are various ways to measure this threshold, where the procedure known as the maximal lactate steady-state (MLSS) is considered the gold standard (Svedahl and MacIntosh, 2003).…”

Analysis of acid–base balance as well as hematological and biochemical parameters in horses of combined driving discipline

“…It should also be taken into account that an increase in lactate concentration in blood may result from poor glucose uptake by the metabolizing tissues (Campbell, 2011). It was demonstrated in a study conducted on Thoroughbreds horses that ran on the treadmill that maximal lactate steady state (maxLASS) within the aerobic-anaerobic threshold should be accepted at a level considerably below 4 mmol L −1 (Lindner, 2010). This study shows that LA level after endurance and speed training is 2.60 mmol L −1 .…”

Optimización del Rendimiento Deportivo en Caninos

“…A niveles submáximos de ejercicio, si no se sobrepasa el umbral, se apreciará un equilibrio entre la producción y eliminación existiendo un estado estable metabólico (García del Moral et al, 1998;Lindner, 2010). A medida que aumenta la intensidad del ejercicio la demanda de energía por unidad de tiempo supera la velocidad con la que puede ser producida en forma aeróbica, y los músculos son inducidos a producir energía en forma anaeróbica (Boffi, 2006), aumentando la cantidad de lactato, sobrepasando el punto de máximo estado estable del lactato en sangre (Lindner, 2010), comenzado a producirse un incremento no lineal (Ghosh, 2004). Este punto se conoce en humanos como umbral de lactato, y equivale a una concentración en sangre de 4 mmol/l de lactato (García del Moral et al, 1998;Ghosh, 2004;Lindner, 2010).…”

“…A medida que aumenta la intensidad del ejercicio la demanda de energía por unidad de tiempo supera la velocidad con la que puede ser producida en forma aeróbica, y los músculos son inducidos a producir energía en forma anaeróbica (Boffi, 2006), aumentando la cantidad de lactato, sobrepasando el punto de máximo estado estable del lactato en sangre (Lindner, 2010), comenzado a producirse un incremento no lineal (Ghosh, 2004). Este punto se conoce en humanos como umbral de lactato, y equivale a una concentración en sangre de 4 mmol/l de lactato (García del Moral et al, 1998;Ghosh, 2004;Lindner, 2010). La detección de dicha concentración es utilizada como punto final para pruebas de ejercicio (Kittleson et al, 1996), y predice de forma eficaz el rendimiento aeróbico (Ghosh En un programa de entrenamiento de resistencia se presentan adaptaciones celulares en el transcurso de las semanas que aumentarán la velocidad de eliminación del lactato, de forma que solo se acumulará a intensidades muy altas de ejercicio (McArdle et al, 2004).…”