Skeletal Muscle Metabolism in Endurance Athletes with Near-Infrared Spectroscopy.

• Autores: Jared Todd Brizendine, kevin K. McCully, Terence Ryan, Rebecca Larson
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 45, Nº. 5, 2013, págs. 869-875
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • AB Purpose: To determine whether near-infrared spectroscopy (NIRS) measurements of muscle mitochondrial function could detect the expected differences between endurance-trained athletes (n = 8) and inactive subjects (n = 8). Methods: Muscle oxygen consumption (mV[spacing dot above]O2) of the vastus lateralis was measured with continuous-wave NIRS using transient arterial occlusions. The recovery rate of mV[spacing dot above]O2 after electrical stimulation was fit to an exponential curve, with the time constant (Tc) used as an index of mitochondrial capacity. Whole-body peak oxygen uptake was determined by indirect calorimetry during a continuous ramp protocol on a cycle ergometer. Results: Whole-body peak oxygen uptake values for endurance-trained and inactive controls were 73.5 +/- 9.1 and 33.7 +/- 5.9 mL[middle dot]kg-1[middle dot]min-1, respectively (P < 0.001). The recovery rates of mV[spacing dot above]O2 after exercise for endurance training were 18.4 +/- 3.2 and 18.8 +/- 2.5 s, whereas those for inactive controls were 32.4 +/- 5.2 and 34.9 +/- 5.9 s for the shallow and deep channels, respectively (P < 0.001 for comparison between groups). Resting mV[spacing dot above]O2 was 0.52%[middle dot]s-1 +/- 0.22%[middle dot]s-1 for endurance athletes and 0.77%[middle dot]s-1 +/- 0.82%[middle dot]s-1 for inactive controls (P = 0.42). Conclusions: The recovery rates of mV[spacing dot above]O2 after exercise in endurance athletes were almost twofold faster than inactive subjects measured with NIRS, consistent with previous studies using muscle biopsies and magnetic resonance spectroscopy. Our results support the use of NIRS measurements of the recovery of oxygen consumption to assess muscle oxidative capacity.