Muscle metabolism, blood @entity880 and XXXX uptake in steady state exercise at aerobic and anaerobic thresholds.

@entity26 @entity880 @entity9659 @entity2723 @entity855
Muscle metabolites and blood @entity880 concentration were studied in five male subjects during five constant-load cycling exercises. The power outputs were below, equal to and above aerobic (AerT) and anaerobic ( @entity9659 ) threshold as determined during an incremental leg cycling test. At AerT, muscle @entity880 had increased significantly (p less than 0.05) from the rest value of 2.31 to 5.56 mmol X kg-1 wet wt. This was accompanied by a significant reduction in @entity2723 by 28% (p less than 0.05), whereas only a minor change (9%) was observed for @entity855 . At @entity9659 muscle @entity880 had further increased and @entity2723 decreased although not significantly as compared with values at AerT. At the highest power outputs (greater than @entity9659 ) muscle @entity880 had increased (p less than 0.01) and @entity2723 decreased (p less than 0.01) significantly from the values observed at @entity9659 . Furthermore, a significant reduction (p less than 0.05) in @entity855 over resting values was recorded. Blood @entity880 decreased significantly (p less than 0.01) during the last half of the lowest 5 min exercise, remained unchanged at AerT and increased significantly (p less than 0.05-0.01) at power outputs greater than or equal to @entity9659 . It is concluded that anaerobic muscle metabolism is increased above resting values at AerT: at low power outputs (less than or equal to AerT) this could be related to the transient @entity26 deficit during the onset of exercise or the increase in power output. At high power outputs (greater than @entity9659 ) anaerobic energy production is accelerated and it is suggested that @entity9659 represents the upper limit of power output where @entity880 production and removal may attain equilibrium during constant load exercise.
