Abstract Aims: To determine lactate threshold (LT) by three different methods (visual inspection, algorithmic adjustment, and Dmax) during an incremental protocol performed in the leg press 45° and to evaluate correlation and agreement among these different methods. Methods: Twenty male long-distance runners participated in this study. Firstly, participants performed the dynamic force tests in one-repetition maximum (1RM). In the next session, completed an incremental protocol consisted of progressive stages of 1 min or 20 repetitions with increments of 10, 20, 25, 30, 35, and 40% 1RM. From 40% 1RM, increments corresponding to 10% 1RM were performed until a load in which the participants could not complete the 20 repetitions. A rest interval of 2 min was observed between each stage for blood collection and adjustment of the workloads for the next stage. Results: Our results showed no significant difference in relative load (% 1RM), good correlations, and high intraclass correlation coefficients (ICC) between algorithmic adjustment and Dmax (p = 0.680, r = 0.92; ICC = 0.959), algorithmic adjustment and visual inspection (p = 0.266, r = 0.91; ICC = 0.948), and Dmax and visual inspection (p = 1.000, r = 0.88; ICC = 0.940). In addition, the Bland-Altman plot and linear regression showed agreement between algorithmic adjustment and Dmax (r2 = 0.855), algorithmic adjustment and visual inspection (r2 = 0.834), and Dmax and visual inspection (r2 = 0.781). Conclusion: The good correlation and high agreement among three methods suggest their applicability to determine LT during an incremental protocol performed in the leg press 45°. However, the best agreement found between mathematical methods suggests better accuracy.

ABSTRACT The growing interest in running as an exercise, and particularly as a sport of competition, demands the study of runner's metabolic efficiency. The estimate of the critical velocity (CV) has been used in different studies to since it is a method of simple applicability to determine the anaerobic threshold of runners, taking into consideration the intensity of effort and the execution time. The objective of the present work was to identify and compare the efficiency of methods that are currently being used for the estimation of runner's CV. A bibliographic review of scientific articles published during the period 2011 to 2016 was carried out. The analysis of the literature showed the estimation of CV is determined by different strategies such as: maximal and submaximal tests, continuous and intermittent, in athletics track, tradmill and asphalt; with different groups of runners. The determination of critical velocity enabled an efficient establishment of the anaerobic threshold of runners, regardless of the group of individuals analyzed in a simpler, less costly, and equally reliable as other more sophisticated methods of anaerobic threshold estimation that require laboratory tests.

RESUMEN El creciente interés en la corrida como ejercicio, y particularmente como deporte de competición, demanda estudiar la eficiencia metabólica que presentan los corredores. La estimación de la velocidad crítica (VC) ha sido utilizada en diferentes estudios por ser de fácil aplicabilidad para determinar el umbral anaeróbico del corredor, considerando la intensidad del esfuerzo y el tiempo en que se ejecuta. El objetivo del presente trabajo fue identificar y comparar la eficiencia de los métodos que están siendo utilizados en la actualidad para la estimación de la VC en corredores. Se realizó una revisión bibliográfica de artículos científicos publicados durante el periodo 2011 a 2016. El análisis de literatura mostró que en la estimación de la VC se emplean diferentes estrategias: test máximos y submáximos, continuos e intermitentes, en pista de atle tismo, trotadora y asfalto; con distintos grupos de corredores. La velocidad crítica permitió establecer eficazmente el umbral anaeróbico de las personas que practican la corrida, independientemente del grupo de individuos analizados, de forma simple, menos costosa, e igual de confiable que otros métodos de estimación del umbral anaeróbico más sofisticados, que requieren pruebas de laboratorio.