FIGURE 2 in How Fast Could Tyrannosaurus rex Run?

FIGURE 2. ESTIMATED EXTENSOR MUSCLE MASS per leg needed to run fast, as a fraction of total body mass. Larger animals need relatively more leg muscle to run. This dependence is illustrated by the solid line, calculated for a chicken scaled up to the size of T. rex. For several models of T. rex anatomy, the estimates (red) all require more leg muscle for running fast than the creature was likely to have had (orange dot). (Adapted from ref. 6.)