Fig. 1. Contraction kinetics of red muscle in rainbow and brook trout. For rainbow trout, activation and relaxation time increased significantly from anterior to posterior (data are from Coughlin, 2000). For brook trout, new data on muscle activation and relaxation are plotted for three body positions (N=10 for anterior and posterior, N=3 for middle). Brook trout show a significant increase in relaxation time from anterior to posterior, but there is no difference in activation rate along the length of these fish. Asterisks indicate statistically significant variation along the length of the fish (P<0.05).