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The Scientific World Journal
Volume 2012, Article ID 769431, 7 pages
http://dx.doi.org/10.1100/2012/769431
Research Article

Aerobic Fitness Evaluation during Walking Tests Identifies the Maximal Lactate Steady State

1Catholic University of Brasília, 72022-900 Brasília, DF, Brazil
2Institute of Bioscience, Department of Physical Education, São Paulo State University, 13506-900 Rio Claro, SP, Brazil
3Department of Physical Education, State University of Londrina, 86051-990 Londrina, PR, Brazil

Received 11 October 2011; Accepted 29 November 2011

Academic Editor: Chad Chase

Copyright © 2012 Guilherme Morais Puga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. The aim of this study was to verify the possibility of lactate minimum (LM) determination during a walking test and the validity of such LM protocol on predicting the maximal lactate steady-state (MLSS) intensity. Design. Eleven healthy subjects ( 2 4 . 2 ± 4 . 5  yr; 7 4 . 3 ± 7 . 7  kg; 1 7 6 . 9 ± 4 . 1  cm) performed LM tests on a treadmill, consisting of walking at 5.5  k m h 1 and with 20–22% of inclination until voluntary exhaustion to induce metabolic acidosis. After 7 minutes of recovery the participants performed an incremental test starting at 7% incline with increments of 2% at each 3 minutes until exhaustion. A polynomial modeling approach (LMp) and a visual inspection (LMv) were used to identify the LM as the exercise intensity associated to the lowest [bLac] during the test. Participants also underwent to 2–4 constant intensity tests of 30 minutes to determine the MLSS intensity. Results. There were no differences among LMv ( 1 2 . 6 ± 1 . 7 %), LMp ( 1 3 . 1 ± 1 . 5 %), and MLSS ( 1 3 . 6 ± 2 . 1 %) and the Bland and Altman plots evidenced acceptable agreement between them. Conclusion. It was possible to identify the LM during walking tests with intensity imposed by treadmill inclination, and it seemed to be valid on identifying the exercise intensity associated to the MLSS.