Table 2.

Parameters of PCr dynamics during recovery from high-intensity intermittent isometric single-leg knee-extensor exercise

	CTRL	FENT
Δ[PCr] (mM)	23.3 ± 2.6	26.0 ± 4.3
Tau (s)	58.4 ± 11.2	62.2 ± 7.7
${\mathrm{V}}_{\text{max}}$(mM·min−1)	26.6 ± 4.7	28.1 ± 3.1
${\text{Vi}}_{\text{PCr}}$ (mM·min−1)	24.4 ± 4.1	25.3 ± 4.5
${\mathrm{H}}_{\text{efflux }}^{+}$(mM·min−1)	5.1 ± 3.3	8.1 ± 3.5

Values are mean ± SD. Intramuscular phosphocreatine (PCr) dynamics during 5 min of recovery were fit with a monoexponential model in control (CTRL) and fentanyl (FENT) conditions. Δ[PCr], amount of PCr resynthesized during the recovery period; Tau, time constant of PCr resynthesis; V_max, peak rate of mitochondrial respiration; Vi_PCr, initial rate of PCr resynthesis; H⁺ efflux, proton efflux from muscle.