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Relationships between maximal muscle oxidative capacity and blood lactate removal after supramaximal exercise and fatigue indexes in humans

¹Laboratoire de Physiologie des Interactions (EA 701), Département de Physiologie, Institut de Biologie, 34060 Montpellier; and ²Efficience et Déficience Motrice (EA 2991), 34090 Montpellier, France

Submitted 8 April 2004 ; accepted in final form 16 June 2004

The present study investigated whether blood lactate removal after supramaximal exercise and fatigue indexes measured during continuous and intermittent supramaximal exercises are related to the maximal muscle oxidative capacity in humans with different training status. Lactate recovery curves were obtained after a 1-min all-out exercise. A biexponential time function was then used to determine the velocity constant of the slow phase (₂), which denoted the blood lactate removal ability. Fatigue indexes were calculated during all-out (FI_AO) and repeated 10-s cycling sprints (FI_Sprint). Biopsies were taken from the vastus lateralis muscle, and maximal ADP-stimulated mitochondrial respiration (V_max) was evaluated in an oxygraph cell on saponin-permeabilized muscle fibers with pyruvate + malate and glutamate + malate as substrates. Significant relationships were found between ₂ and pyruvate + malate V_max (r = 0.60, P < 0.05), ₂ and glutamate + malate V_max (r = 0.66, P < 0.01), and ₂ and citrate synthase activity (r = 0.76, P < 0.01). In addition, ₂, glutamate + malate V_max, and pyruvate + malate V_max were related to FI_AO (₂ – FI_AO: r = 0.85; P < 0.01; glutamate + malate V_max – FI_AO: r = 0.70, P < 0.01; and pyruvate + malate V_max – FI_AO: r = 0.63, P < 0.01) and FI_Sprint (₂ – FI_Sprint: r = 0.74, P < 0.01; glutamate + malate V_max – FI_Sprint: r = 0.64, P < 0.01; and pyruvate + malate V_max – FI_Sprint: r = 0.46, P < 0.01). In conclusion, these results suggested that the maximal muscle oxidative capacity was related to blood lactate removal ability after a 1-min all-out test. Moreover, maximal muscle oxidative capacity and blood lactate removal ability were associated with the delay in the fatigue observed during continuous and intermittent supramaximal exercises in well-trained subjects.

lactate kinetics; biexponential mathematical model; all-out exercise; saponin-permeabilized muscle fibers

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				B. Roels, C. Thomas, D. J. Bentley, J. Mercier, M. Hayot, and G. Millet Effects of intermittent hypoxic training on amino and fatty acid oxidative combustion in human permeabilized muscle fibers J Appl Physiol, January 1, 2007; 102(1): 79 - 86. [Abstract] [Full Text] [PDF]

				C. Thomas, S. Perrey, K. Lambert, G. Hugon, D. Mornet, and J. Mercier Monocarboxylate transporters, blood lactate removal after supramaximal exercise, and fatigue indexes in humans J Appl Physiol, March 1, 2005; 98(3): 804 - 809. [Abstract] [Full Text] [PDF]