Teste cardiopulmonar de exercício com resistência elástica: uma nova proposta reprodutível para determinação do limiar ventilatório e do consumo máximo de oxigênio

Abstract

Objectives: To propose a new cardiopulmonary exercise test with elastic resistance (CPxEL) and to compare the physiological responses to the conventional cardiopulmonary exercise test (CPx) performed on a treadmill. Method: A total of 24 physically active participants completed the CPx (first session) and CPxEL twice (second and third sessions) interspersed for seven days. A treadmill protocol with increments of 1km·h-1 every minute until exhaustion was used in CPx. The CPxEL consisted of performing alternating back and forth steps, against an elastic resistance attached to a belt. An incremental protocol with 1 stage (S) per minute was used on an 8-stage rubber mat following a cadence of 200 bpm controlled by a metronome. Two analyzes were performed. The first analysis evaluated the agreement by Bland-Altman analysis between CPx vs. CPxEL, paired t test and effect size. The second analysis evaluated the reproducibility of CPxEL by analyzing the reliability, variability and sensitivity of the test. Results: First analysis: Ventilatory Threshold (VT1) occurred at 69.7% and 75.3% of HRmax and 53.5% and 65.7% of V ̇ O2max. LV2 occurred in 93.3% and 96.8% of HRmax and 87.0% and 96.9% of V ̇ O2max for CPET and CPETE, respectively. At exhaustion, V ̇ O2max, BORGCR10 and OMNI-RES EB and test duration showed lower values for CPxEL (P < 0.05). Second analysis: LV1 occurred at warm-up (S0) (P = 0.731), LV2 occurred at S5 (P = 0.912) and exhaustion occurred at S6 and S7 (P = 0.271) for CPxEL and Retest, respectively. V ̇ O2max presented ICC = 0.921 and HRmax, ICC = 0.930. Conclusion: The CPxEL has good test-retest reproducibility and represents a possible and interesting complement to determine the maximum oxygen consumption, the maximum heart rate and the second ventilatory threshold without the use of traditional ergometers.