Figure 9.
Length changes, stimulation pattern, force production and work output of red muscle during swimming. Step 1 was to measure in a swimming (80 cm s−1) fish the (a) EMGs and (b) length changes for the red muscle at four places along the length of the fish pictured. Step 2 was to impose on muscle bundles isolated from these four positions the (d) length changes and (c) stimulation pattern that were observed during swimming. Step 3 was to measure in the isolated muscle the resulting (e) force production and (f) work production. Traces a to e are all functions of time. Trace f is a plot of force produced against length changes where the area of the enclosed loop is the work produced during a tail-beat cycle. This value is much larger in the POST than in the ANT-1 position. Adapted from Rome et al. (1993).