title: Is the balance between skeletal muscular metabolic capacity and oxygen supply capacity the same in endurance trained and untrained subjects?
abstract: We attempted to test whether the balance between muscular metabolic capacity and oxygen supply capacity in endurance-trained athletes (ET) differs from that in a control group of normal physically active subjects by using exercises with different muscle masses. We compared maximal exercise in nine ET subjects [Maximal oxygen uptake (VO(2)max) 64 ml kg(-1) min(-1) +/- SD 4] and eight controls (VO(2)max 46 +/- 4 ml kg(-1) min(-1)) during one-legged knee extensions (1-KE), two-legged knee extensions (2-KE) and bicycling. Maximal values for power output (P), VO(2)max, concentration of blood lactate ([La(-)]), ventilation (VE), heart rate (HR), and arterial oxygen saturation of haemoglobin (SpO(2)) were registered. P was 43 (2), 89 (3) and 298 (7) W (mean +/- SE); and VO(2)max: 1,387 (80), 2,234 (113) and 4,115 (150) ml min(-1)) for controls in 1-KE, 2-KE and bicycling, respectively. The ET subjects achieved 126, 121 and 126% of the P of controls (p < 0.05) and 127, 124, and 117% of their VO(2)max (p < 0.05). HR and [La(-)] were similar for both groups during all modes of exercise, while VE in ET was 147 and 114% of controls during 1-KE and bicycling, respectively. For mass-specific VO(2)max (VO(2)max divided by the calculated active muscle mass) during the different exercises, ET achieved 148, 141, and 150% of the controls' values, respectively (p < 0.05). During bicycling, both groups achieved 37% of their mass-specific VO(2) during 1-KE. Finally we conclude that ET subjects have the same utilization of the muscular metabolic capacity during whole body exercise as active control subjects.
authors.affiliation: Section of Physical Performance, Norwegian School of Sport Sciences, Pb. 4014, Ullevål Stadion, 0806, Oslo, Norway, bjarne.rud@nih.no
authors.forename: Bjarne
authors.initials: B
authors.lastname: Rud
authors.forename: Jostein
authors.initials: J
authors.lastname: Hallén
mesh_terms: D000328:Adult; D001642:Bicycling; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness