Resumen de Influence of Different Treadmill Inclinations on V[Combining Dot Above]O2max and Ventilatory Thresholds During Maximal Ramp Protocols
Sidney Cavalcante da Silva, Walace David Monteiro, Felipe Amorim Da Cunha, Paulo de Tarso Veras Farinatti
Ramp protocols for cardiopulmonary exercise testing (CPET) lack precise recommendations, including optimal treadmill inclination. This study investigated the impact of treadmill grades applied in ramp CPETs on maximal oxygen uptake (V[Combining Dot Above]O2max), ventilatory thresholds (VT1/VT2), and V[Combining Dot Above]O2 vs. workload relationship. Twenty-one healthy men (age 33 +/- 8 years; height 176.6 +/- 5.8 cm; body mass 80.4 +/- 8.7 kg; and V[Combining Dot Above]O2max 44.9 +/- 5.7 ml[middle dot]kg-1[middle dot]min-1) and 12 women (age 29 +/- 7 years; height 163.3 +/- 6.7 cm; body mass 56.6 +/- 6.3 kg; and V[Combining Dot Above]O2max 39.4 +/- 4.9 ml[middle dot]kg-1[middle dot]min-1) underwent ramp CPETs with similar speed increments and different treadmill grades: CPET0%, CPET2%, CPET3.5%, and CPET5.5%. The V[Combining Dot Above]O2max was similar across protocols (42.8-43.2 ml[middle dot]kg-1[middle dot]min-1, p = 0.76), albeit duration of CPETs shortened when treadmill inclination increased (CPET0% 12.7 minutes; CPET2% 9.1 minutes; CPET3.5% 8.0 minutes; and CPET5.5% 6.6 minutes; p < 0.01). The %V[Combining Dot Above]O2max corresponding to VT1 was slightly lower in CPET0% (63.6%) and higher in CPET5.5% (75.8%) vs. CPET2% (67.8%) and CPET3.5% (69.5%; p < 0.05), whereas VT2 was not affected by treadmill inclination (95.1-95.8% V[Combining Dot Above]O2max; p > 0.05). V[Combining Dot Above]O2max and ventilatory thresholds were similar in CPETs performed with different treadmill inclinations and similar initial/final speeds. However, linear regressions between workload and V[Combining Dot Above]O2 were closer to the identity line in CPETs performed with smaller (CPET0% and CPET2%) than with greater (CPET3.5% and CPET5.5%) inclinations. These data suggest that in healthy young adults, ramp CPETs performed with inclinations of 0-2% degree should be preferred over protocols with greater inclinations.
