Fig. 1

Visual representation of exercise intensity domains. The moderate intensity domain is hallmarked by achievement of steady-state \({\dot{\text{V}}\text{O}}_{2}\), and minimal [Lactate] or [K⁺] accumulation occurs. It is capped by the gas exchange threshold (GET). Hallmark features of the heavy domain include a delay in achieving a steady-state \({\dot{\text{V}}\text{O}}_{2}\) and a rise but stabilisation of [Lactate]; its upper boundary is CP. The severe domain encompasses all work done above CP, and is limited by a finite capacity (W′). \({\dot{\text{V}}\text{O}}_{2}\) and [Lactate] kinetics do not reach steady state and muscle [PCr] and pH reach low values [5]. Figure adapted from Jones et al. [11] and reused under Creative Commons License