Fig 4. Output simulation work-loops.

Muscle work-loops showing normalized muscle force ${\widehat{F}}_{\mathrm{m}}$ versus normalized muscle length ${\widehat{l}}_{\mathrm{m}}$ for each simulation. Simulations with u_max of 0.1 are shown in panels A and C, and simulations with u_max of 1 are shown in B and D. The non-dimensional muscle forces and lengths are identical for simulations with ${\lambda }_l{}_{{}_0}$ of 1 (A,B) and 10 (C,D).