Validity of a Single-Visit Protocol to Estimate the Maximum Lactate Steady State

• Autores: Andrew M. Jones, Andrew E. Kilding
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 37, Nº. 10 (Octubre), 2005, págs. 1734-1740
• Idioma: inglés
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• Dialnet Métricas: 1 Cita
• Resumen

  • Introduction: The maximum lactate steady state (MLSS) represents the highest intensity of exercise at which a balance exists between the rate of lactate production and the rate of lactate clearance. The MLSS is an important determinant of endurance exercise performance but its determination, which involves 4-5 laboratory visits, is labor-intensive and time consuming.

    Purpose: To compare the MLSS estimated from a single-visit protocol (MLSSsingle) with the traditional, directly measured MLSS (MLSStrad).

    Methods: Following an incremental treadmill test for the determination of [latin capital V with dot above]O2peak, eight endurance-trained runners completed: 1) a series of 4-5 constant-speed treadmill runs of up to 30-min duration, on separate days, for determination of the MLSStrad; and 2) a single-visit protocol consisting of two constant-speed treadmill runs of 20-min duration at approximately 65 and 90% [latin capital V with dot above]O2peak separated by 40 min of rest, for determination of MLSSsingle. Blood lactate concentration ([La]), oxygen uptake ([latin capital V with dot above]O2), and heart rate (HR) were measured every 5 min in all treadmill runs. Comparisons between values were made using paired t-tests.

    Results: The MLSSsingle significantly underestimated the MLSStrad with respect to speed (13.4 +/- 1.2 vs 16.4 +/- 1.6 km[middle dot]h-1, P = 0.002), HR (148 +/- 8 vs 170 +/- 10 b[middle dot]min-1, P < 0.001), blood [La] (2.3 +/- 1.5 vs 3.9 +/- 1.0 mmol[middle dot]L-1; P = 0.01), and %[latin capital V with dot above]O2peak utilized (75 +/- 8 vs 90 +/- 2%, P = 0.002). The MLSStrad speed and MLSSsingle speed were poorly correlated (r = 0.29, P = 0.49).

    Conclusion: The single-visit method of determining the MLSS substantially underestimates the actual MLSS.