
Computational modeling of muscle biomechanics 177
is more variable (0.9–1.3 μ m) (Walker and Schrodt, 1974). The cross-bridge
theory (Huxley, 1957) of muscle contraction assumes that muscle force is
generated by cyclic formation of cross-bridges between actin and myosin
laments. More precisely, myosin heads (the independent force generators)
bind to actin at speci c sites (forming cross-bridges) and pull the actin la-
ment by head rotation (Huxley, 1969). This work stroke translates the actin
lament by about 5 nm and produces a force of about 10 pN, which results
in sliding of myosin and actin laments and muscle force development. ...