Long maximal incremental tests accurately assess aerobic fitness in class II and III obese men

Abstract

This study aimed to compare two different maximal incremental tests with different time durations [a maximal incremental ramp test with a short time duration (8-12 min) (STest) and a maximal incremental test with a longer time duration (20-25 min) (LTest)] to investigate whether an LTest accurately assesses aerobic fitness in class II and III obese men. Twenty obese men (BMI≥35 kg.m-2) without secondary pathologies (mean±SE; 36.7±1.9 yr; 41.8±0.7 kg*m-2) completed an STest (warm-up: 40 W; increment: 20 W*min-1) and an LTest [warm-up: 20% of the peak power output (PPO) reached during the STest; increment: 10% PPO every 5 min until 70% PPO was reached or until the respiratory exchange ratio reached 1.0, followed by 15 W.min-1 until exhaustion] on a cycle-ergometer to assess the peak oxygen uptake [Formula: see text] and peak heart rate (HRpeak) of each test. There were no significant differences in [Formula: see text] (STest: 3.1±0.1 L*min-1; LTest: 3.0±0.1 L*min-1) and HRpeak (STest: 174±4 bpm; LTest: 173±4 bpm) between the two tests. Bland-Altman plot analyses showed good agreement and Pearson product-moment and intra-class correlation coefficients showed a strong correlation between [Formula: see text] (r=0.81 for both; p≤0.001) and HRpeak (r=0.95 for both; p≤0.001) during both tests. [Formula: see text] and HRpeak assessments were not compromised by test duration in class II and III obese men. Therefore, we suggest that the LTest is a feasible test that accurately assesses aerobic fitness and may allow for the exercise intensity prescription and individualization that will lead to improved therapeutic approaches in treating obesity and severe obesity.

Fig 1. Correlations between A peak oxygen uptake (V˙O2peak; y = 0.81x + 0.51, r = 0.81, p≤0.001), C peak heart rate (HR_peak; y = 0.96x + 6.23; r = 0.95, p≤0.001) and E peak power output (PPO; y = 0.84x - 4.55; r = 0.89, p≤0.001), and Bland-Altman plots of the absolute differences between BV˙O2peak, D HR_peak and F PPO determined during maximal incremental test with short (S_Test) and long (L_Test) time duration.

In A, C and E, the dotted line represents the line of identity. In B, D and F, the light dotted line represents the bias from the mean difference, and the dark dotted line represents the upper and lower 95% limits of agreement.

Fig 2. Correlations between A oxygen uptake at ventilatory threshold 1 (V˙O2VT1; y = 0.75x + 0.35; r = 0.72, p≤0.001), C heart rate at VT₁ (HR_VT1; y = 0.69x + 29.98; r = 0.67, p = 0.001) and E power output at VT₁ (PO_VT1; y = 0.71x + 8.21; r = 0.73, p≤0.001), and Bland-Altman plots of the absolute differences between BV˙O2VT1, D HR_VT1 and F PO_VT1 determined during maximal incremental test with short (S_Test) and long (L_Test) time duration.

In A, C and E, the dotted line represents the line of identity. In B, D and F, the light dotted line represents the bias from the mean difference, and the dark dotted line represents the upper and lower 95% limits of agreement.