Salvadego 2013 J Appl Physiol
Salvadego D, Domenis R, Lazzer S, Porcelli S, Rittweger J, Rizzo G, Mavelli I, Simunic B, Pisot R, Grassi B (2013) Skeletal muscle oxidative function in vivo and ex vivo in athletes with marked hypertrophy from resistance training. J Appl Physiol 114:1527-35. |
Salvadego D, Domenis R, Lazzer S, Porcelli S, Rittweger J, Rizzo G, Mavelli I, Simunic B, Pisot R, Grassi B (2013) J Appl Physiol
Abstract: Oxidative function during exercise was evaluated in 11 young athletes with marked skeletal muscle hypertrophy induced by long-term resistance training (RTA; body mass 102.6 Β± 7.3 kg, mean Β± SD) and 11 controls (CTRL; body mass 77.8 Β± 6.0 kg). Pulmonary O2 uptake (VO2) and vastus lateralis muscle fractional O2 extraction (by near-infrared spectroscopy) were determined during an incremental cycle ergometer (CE) and one-leg knee-extension (KE) exercise. Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibers obtained by biopsy. Quadriceps femoris muscle cross-sectional area, volume (determined by magnetic resonance imaging), and strength were greater in RTA vs. CTRL (by βΌ40%, βΌ33%, and βΌ20%, respectively). VO2peak during CE was higher in RTA vs. CTRL (4.05 Β± 0.64 vs. 3.56 Β± 0.30 l/min); no difference between groups was observed during KE. The O2 cost of CE exercise was not different between groups. When divided per muscle mass (for CE) or quadriceps muscle mass (for KE), VO2peak was lower (by 15-20%) in RTA vs. CTRL. Vastus lateralis fractional O2 extraction was lower in RTA vs. CTRL at all work rates, during both CE and KE. RTA had higher ADP-stimulated mitochondrial respiration (56.7 Β± 23.7 pmol O2Β·s-1Β·mg-1 ww) vs. CTRL (35.7 Β± 10.2 pmol O2Β·s-1Β·mg-1 ww) and a tighter coupling of oxidative phosphorylation. In RTA, the greater muscle mass and maximal force and the enhanced mitochondrial respiration seem to compensate for the hypertrophy-induced impaired peripheral O2 diffusion. The net results are an enhanced whole body oxidative function at peak exercise and unchanged efficiency and O2 cost at submaximal exercise, despite a much greater body mass. β’ Keywords: Mitochondrial respiration, Oxidative metabolism during exercise, Skeletal muscle hypertrophy
β’ O2k-Network Lab: IT Udine Grassi B, IT Udine Mavelli I
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Organism: Human
Tissue;cell: Skeletal muscle
Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS
HRR: Oxygraph-2k