The aim of this study was to test the utility and effectiveness of an alternative computational approach to threshold-intensities based on time dependent change-points in minute ventilation divided by end-tidal partial pressure of CO₂ (V_E/P_ETCO₂) to reveal whether respiratory compensation point (RCP) is a third ventilatory threshold, or not. Ten recreationally active young adults and ten well-trained athletes volunteered to take part in this study. Following incremental ramp tests, gas exchange threshold (GET) and respiratory compensation point (RCP) were respectively evaluated by the slopes of VCO₂-VO₂ and V_E-VCO₂ using the Innocor system automatically. Respiratory threshold (RT) was analysed based on time dependent change-points in the V_E/P_ETCO₂ using binary segmentation algorithm. Additionally, those intersections were analysed independently by two experienced investigators using a visual identification technique in a double-blind design. According to the results, in the recreationally active group, there were the first (GET₁) and the second (GET₂) gas exchange thresholds which were identical with the RT₁ (139 W; 1.9 L⋅min⁻¹ of VO₂; 1.73 L⋅min⁻¹ of VCO₂; 49.9 L⋅min⁻¹ of V_E versus 139 W; 1.88 L⋅min⁻¹; 1.7 L⋅min⁻¹; 49 L⋅min⁻¹, respectively) and RT₂ (186 W; 2.39 L⋅min⁻¹ of VO₂; 2.44 L⋅min⁻¹ of VCO₂; 66 L⋅min⁻¹ of V_E versus 187 W; 2.41 L⋅min⁻¹; 2.49 L⋅min⁻¹; 65.7 L⋅min⁻¹, respectively). However, there were three threshold intensities which were determined by GET₁, GET₂, and RCP in well-trained athletes. Additionally, RT₁, RT₂, and RT₃ were determined as valid surrogates of the GET₁ (194 W; 2.56 L⋅min⁻¹ of VO₂; 1.99 L⋅min⁻¹ of VCO₂; 57.5 L⋅min⁻¹ of V_E versus 192 W; 2.61 L⋅min⁻¹; 1.99 Lmin⁻¹; 57.7 L⋅min⁻¹, respectively), GET₂ (267 W; 3.6 L⋅min⁻¹ of VO₂; 3.29 L⋅min⁻¹ of VCO₂; 94.5 L⋅min⁻¹ of V_E versus 266 W; 3.58 L⋅min⁻¹; 3.26 L⋅min⁻¹; 93.4 L⋅min⁻¹, respectively), and RCP (324 W; 4.05 L⋅min⁻¹ of VO₂; 4.13 L⋅min⁻¹ of VCO₂; 124 L⋅min⁻¹ of V_E versus 322 W; 4.02 L⋅min⁻¹; 4.07 L⋅min⁻¹; 122 L⋅min⁻¹, respectively) in well-trained athletes. There were high levels of agreements between the power outputs determined by traditional techniques and newly proposed change-points in RT. All markers were strongly correlated (p < 0.001). It was shown that RT technique can provide an accurate threshold determination. Furthermore, the RCP was observed as a third threshold-intensity for well-trained athletes but not for recreationally active young adults.

本研究的目的是测试阈值强度的替代计算方法的实用性和有效性，该方法基于每分钟通气量的时间依赖性变化点除以 CO ₂的呼气末分压(V _E /P _ET CO ₂ )揭示呼吸补偿点 (RCP) 是否是第三通气阈值。十名休闲活跃的年轻人和十名训练有素的运动员自愿参加这项研究。在增量斜坡测试之后，分别通过 VCO ₂ -VO ₂和 V _E -VCO _{2的斜率评估气体交换阈值（GET）和呼吸补偿点（RCP）}自动使用 Innocor 系统。_{呼吸阈值 (RT) 基于 V E} /P _ET CO ₂中的时间相关变化点使用二元分割算法进行分析。此外，两名经验丰富的研究人员在双盲设计中使用视觉识别技术独立分析了这些交叉点。结果显示，在休闲活动组中，第一（GET ₁）和第二（GET ₂）气体交换阈值与RT ₁相同（139 W； VO ₂ 1.9 L·min ^-1；VCO ₂ 1.73 L⋅min ^-1；49.9 L⋅min ^-1V _E与 139 W；1.88 L⋅min ^-1 ; 1.7 L·min ^-1 ; 分别为49 L⋅min ^-1）和 RT ₂（186 W；VO _{2的 2.39 L⋅min} ^-1 ； VCO ₂的2.44 L⋅min ^-1 ； V _E的66 L⋅min ^-1与 187 W 相比；2.41 L⋅min ^-1；2.49 L⋅min ^-1；65.7 L⋅min ^-1）。然而，在训练有素的运动员中，存在由 GET ₁、 GET _{2和 RCP 确定的三个阈值强度。}此外，RT ₁、RT ₂和 RT₃被确定为 GET ₁的有效替代物（194 W； VO ₂的2.56 L·min ^-1 ； VCO ₂的1.99 L·min ^-1 ； V _E的57.5 L·min ^-1与 192 W；2.61 L· min ^-1 ; 1.99 Lmin ^-1 ; 57.7 L⋅min ^-1 )，GET ₂ (267 W; 3.6 L⋅min ^-1 of VO ₂ ; 3.29 L⋅min ^-1 of VCO ₂ ; 94.5 L⋅min ^{- 1} V _E与 266 W；3.58 L⋅min ^-1；3.26 L⋅min ^-1；93.4 L⋅min ^-1，分别）和RCP（324 W； VO ₂的4.05 L·min ^-1 ； VCO ₂的4.13 L·min ^-1 ； V _E的124 L·min ^-1对比 322 W；4.02 L·min ^-1； 4.07 L⋅min ^-1 ; 122 L⋅min ^-1，分别）在训练有素的运动员。传统技术确定的功率输出与 RT 中新提出的变化点之间存在高度一致。所有标志物都高度相关（p < 0.001）。结果表明，RT技术可以提供准确的阈值确定。此外，RCP 被观察为训练有素的运动员的第三阈值强度，但不适用于休闲活动的年轻人。