Purpose: To (1) compare the power output (PO) for both the 20-minute functional threshold power (FTP₂₀) field test and the calculated 95% (FTP_95%) with PO at maximal lactate steady state (MLSS) and (2) evaluate the sensitivity of FTP_95% and MLSS to training-induced changes. Methods: Eighteen participants (12 males: 37 [6] y and 6 females: 28 [6] y) performed a ramp-incremental cycling test to exhaustion, 2 to 3 constant-load MLSS trials, and an FTP₂₀ test. A total of 10 participants returned to repeat the test series after 7 months of training. Results: The PO at FTP₂₀ and FTP_95% was greater than that at MLSS (P = .00), with the PO at MLSS representing 88.5% (4.8%) and 93.1% (5.1%) of FTP and FTP_95%, respectively. MLSS was greater at POST compared with PRE training (12 [8] W) (P = .002). No increase was observed in mean PO at FTP₂₀ and FTP_95% (P = .75). Conclusions: The results indicate that the PO at FTP_95% is different to MLSS, and that changes in the PO at MLSS after training were not reflected by FTP_95%. Even when using an adjusted percentage (ie, 88% rather than 95% of FTP₂₀), the large variability in the data is such that it would not be advisable to use this as a representation of MLSS.