F-16 Free Communication/Slide - Advancing Physical Activity Assessment Methods - Part 2

Abstract

Variations in the protocol for incremental exercise testing in rowing ergometry may affect the accuracy of the determination of the lactate thresholds. PURPOSE: The purpose of this study was to identify the minimum protocol durations necessary to accurately assess the lactate thresholds relative to the criterion measure of maximal lactate steady state (MLSS). METHODS: Twenty-one elite rowers (12 female, 9 males) each performed a series of 8-9 rowing tests in randomised, counterbalanced order. These tests comprised: 1) Five progressive incremental tests consisting of up to seven intervals of 3, 4, 5, 7 or 10 min duration; and 2) MLSS assessments using a series of at least three 30 min constant-intensity tests. Test comparisons were made using two-way ANOVA with repeated measures. The level of statistical significance was set at an α level of p ≤ 0.05. RESULTS: The power output (PO) calculated at the lactate threshold (LT1) was significantly higher in the 3 and 4-min step duration tests. No other physiological measures were significantly different for LT1. The PO calculated at the anaerobic threshold (LT2) in the progressive incremental tests was significantly different for all step durations and was significantly higher than the measured PO at MLSS except for the 10 min intervals. Oxygen consumption (VO2) at LT2 was significantly higher in the 3-, 4-, 5-min incremental tests. Heart rate (HR) and rating of perceived exhaustion (RPE) at LT2 were not significantly different between incremental tests. The mean peak PO during the incremental tests was inversely related to the stage durations (r2 = 0.86, p ≤ 0.02). Mean peak VO2 was significantly higher in the shorter duration incremental tests (≤ 5 min) compared with the longer duration incremental tests (≥ 7 min). Peak HR was not significantly different between tests. CONCLUSIONS: The data obtained in this study suggest: 1) incremental exercise tests with work increment durations shorter than 10 min overestimate MLSS exercise intensity; 2) Peak physiological values are best determined during incremental exercise tests with interval durations up to 4 min; and 3) Peak HR and HR at LT1 and LT2 are not affected by test duration and therefore prescription of training HR will not be influenced by different work increment durations.