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

Guilherme Morais Puga,Fabio Yuzo Nakamura,Carmen Sílvia Grubert Campbell,Eduardo Kokubun,Herbert Gustavo Simões

doi:10.1100/2012/769431

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 (24.2 ± 4.5 yr; 74.3 ± 7.7 kg; 176.9 ± 4.1 cm) performed LM tests on a treadmill, consisting of walking at 5.5 km · 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 (12.6 ± 1.7%), LMp (13.1 ± 1.5%), and MLSS (13.6 ± 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.

Highlights

The blood lactate responses during incremental test preceded by a high-intensity exercise exhibit an U-shape pattern
The lactate minimum (LM) test has been applied in several exercise modes and conditions [2,3,4,5,6,7] and shown to be associated to the maximal lactate steady state (MLSS) [3, 4, 7, 8] which is the gold standard among protocols of aerobic fitness evaluation derived from the [bLac] responses to exercise [9, 10]
The peak VO2, VCO2, ventilation per minute (VE), heart rate (HR), and rating of perceived exertion (RPE) values at exhaustion in the incremental test were significantly higher (P < 0.01) than the ones corresponding to maximal lactate steady-state (MLSS) or LMv

Summary

Introduction

The blood lactate responses during incremental test preceded by a high-intensity exercise exhibit an U-shape pattern. The LM test has been applied in several exercise modes and conditions [2,3,4,5,6,7] and shown to be associated to the maximal lactate steady state (MLSS) [3, 4, 7, 8] which is the gold standard among protocols of aerobic fitness evaluation derived from the [bLac] responses to exercise [9, 10]. To our knowledge the LM protocol has not been applied on walking as an exercise mode yet. Walking is an exercise mode practiced by most people of any age or aerobic fitness level [12]. Walking produces less risk for musculoskeletal lower extremity injury than running because it is associated with

Methods

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Discussion

Conclusion