Fig. 4.

Effects of interval sprint training (IST) (10 wk of 6 training bouts/day, 5 days/wk, with each rat running 60 m/min up a 15% incline for 2.5 min with 4.5 min of rest between bouts) and endurance training (ET) (10 to 12 wk of treadmill running at 30 m/min, 60 min/day, 5 days/wk) on oxidative capacity (cytochrome-c concentrations), blood flow capacity, capillary density, and arteriolar density in the white (G_W) and red (G_R) portions of the gastrocnemius and soleus muscles of rats. These results demonstrate that training-induced changes in arteriolar density do not explain changes in blood flow capacity. Data are expressed as a percent increase above respective values of sedentary rats. Results demonstrate that IST increases G_W oxidative capacity and blood flow capacity the most, and that these changes are correlated with increases in capillary density and small increases in arteriolar density. Results indicate that ET increased oxidative capacity and blood flow capacity the most in soleus and G_R muscles. In contrast to IST, changes in oxidative and blood flow capacity were not correlated with changes in capillary or arteriolar density in the soleus muscle. [Published with permission (34, 42, 43, 65, 66, 68, 74).]