Human Performance Across the Extreme- and Severe-Intensity Domains: Insights from Decremental and Priming Exercise Protocols

Purpose: – To investigate whether W′ in the extreme-intensity domain is smaller, yet linked to the W′ predicted by the severe-intensity time series. Methods: – Twelve recreationally active participants (four females) completed 1) three extreme-intensity and three severe-intensity constant-power output (PO) trials to establish the PO duration series and to obtain W′ within their respective domains (W′_EXT and W′_SVR, respectively); 2) two decremental protocols from extreme-to-severe (EXT₁→SVR₃) and from severe-to-severe POs (SVR₂→SVR₃); 3) one extreme- and one severe-intensity constant-PO trial preceded by priming exercise (EXT_1P and SVR_2P, respectively); and 4) control extreme- and severe-intensity constant-PO trials. Peak values for oxygen uptake (V̇O_2peak), blood lactate concentration ([La−]_b-peak), and minute ventilation (V̇_Epeak) were also analyzed. Results: – W′_EXT was significantly smaller than W′_SVR (P < 0.001). There was no difference in W′ between the composite EXT₁→SVR₃ and SVR₂→SVR₃ and SVR₃ alone (all P > 0.05). Priming-induced increase in W′_EXT and W′_SVR was not different (P = 0.401). V̇O_2peak, V̇_Epeak, and [La−]_b-peak were all greater in EXT_1P compared with EXT₁ (all P < 0.05). Conclusions: – We showed that W′_EXT is smaller than W′_SVR during cycling. Following task failure during EXT₁, more work could be performed at SVR₃ until complete depletion of W′_SVR. Additionally, heavy-intensity priming exercise increased W′_EXT and W′_SVR by a similar magnitude. Collectively, these findings suggest that performance within the extreme-intensity domain is limited by mechanisms, at least in part, different from those that limit performance within the severe-intensity domain.