Fig. 5. Simultaneous recordings of red muscle (RM; red traces) and white muscle (WM; gray traces) strain at 0.6L on the right and left sides of the body during passive and active swimming in the mako. Numbers in A represent locations of implanted sonomicrometric crystals (1, WM near backbone on right side of the body; 2, RM on right side; 3, RM on left side). During passive simulated swimming movements (B), shortening in the red and white muscle on the right side of the body are in phase but 180° out of phase with shortening on the left side (vertical line), as expected. During active swimming (C), shortening in WM precedes shortening in RM by nearly 50% of the tailbeat cycle (box).