Influence of training following bilateral stenosis of the femoral artery in rats.

The influence of training on muscle performance in situ, exercise tolerance in vivo, and muscle blood flow, was assessed in rats in which femoral arteries were previously surgically constricted to severely limit active hyperemia but not to restrict normal resting blood flow (BF). Muscle BF to the different fiber type sections of the gastrocnemius plantaris soleus muscle group was determined during in situ stimulation (15 and 30 tetani/min) using 15-microns microspheres after 0, 1, 2, 3, and 5 wk (n = 5-6/wk) of daily treadmill training. Surgical stenosis was performed 48 h prior to the initiation of training. The ability of the hindlimb muscle of sedentary stenosed animals to maintain tension in situ improved from an extensive deficit to normal at 3 wk during relatively mild contractions (15 tetani/min) but not at 5 wk during 30 tetani/min. Although BF improved to normal at 15 tetani/min, a large BF deficit remained at 30 tetani/min. Exercise tolerance during running increased approximately twofold in duration. In contrast, trained stenosed animals demonstrated normal muscle tension in situ by 2 wk during 15 tetani/min and at 5 wk during 30 tetani/min. Exercise tolerance during running increased in duration (approximately fivefold) and intensity (approximately twofold). Although BF to the entire contracting muscle mass was not different between trained and sedentary stenosed animals, its distribution within the gastrocnemius was more homogenous (P less than 0.001). This was probably due to adaptations within the fast-twitch white muscle section and could have contributed to the dramatic improvement in muscle function and exercise tolerance exhibited by the trained stenosed animals.