Identification of maximal steady-state metabolic rate by the change in muscle oxygen saturation.

We tested the hypothesis that a %SmO (muscle O saturation) slope can distinguish the heavy-severe exercise domain boundary and the highest steady-state metabolic rate. Thirteen participants (5 women) performed a graded exercise test (GXT) to determine peak oxygen consumption (V̇o) and lactate turn point (LTP). On a separate study day, a %SmO zero-slope prediction trial included completing 5-min cycling bouts in an estimated heavy domain, at an estimated critical power, and in an estimated severe domain.