Comparison of Physiological Responses between a W´BAL-INT Training Model and a Critical Power Test

This study aimed to compare acute physiological responses during the W prime (W´) balance training model (W´BAL-INT) with performance in the critical power test (CP_Test). Additionally, the study sought to determine the extent of neuromuscular and metabolic fatigue associated with severe and extreme intensity domains. Fourteen road master cyclists (13 male, 1 female) completed graded incremental exercise tests to determine their maximum oxygen uptake and 12-, 7- and 3-min maximal efforts to assess CP and W´ (CP_Test). Additionally, they participated in a reconstitutive intermittent training session following the W´BAL-INT model. Physiological responses including oxygen uptake (V˙O₂), the heart rate (HR), blood lactate (BLa̅) concentration, and perceptual responses (RPE), were measured and compared to CP_Test performance data. The W´BAL-INT induced steady-state physiological responses in V˙O_2mean (F = 0.76, p = 0.655) and absolute HR, relative HR and HR_CP (F = 0.70, p = 0.704; F = 1.11, p = 0.359; F = 1.70, p = 0.095, respectively) comparable to CP_Test. During the 3-min work intervals in the training session, V˙O₂ was stable and similar to V˙O_2peak (54.2 ± 6.7 to 59.3 ± 4.9 ml·kg^-1·min^-1) in the CP_Test. Furthermore, 4-min rest intervals facilitated recovery up to moderate fatigue levels (80-100% of W´ balance). HR responses were sensitive to interval intensity and accumulated time. Meanwhile, BLa̅ responses and the RPE increased fatigue development during W´BAL-INT. The W´BAL-INT training model generates consistent physiological responses in mean oxygen kinetics, the percentage of CP and the HR, similar to those observed during the CP_Test. However, different physiological responses were observed in peak oxygen kinetics and W´ energy balance.