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A Mathematical Model Of Muscle Containing Heterogeneous Half-Sarcomeres Exhibits Residual Force Enhancement, Stuart G. Campbell, P. Chris Hatfield, Kenneth S. Campbell
A Mathematical Model Of Muscle Containing Heterogeneous Half-Sarcomeres Exhibits Residual Force Enhancement, Stuart G. Campbell, P. Chris Hatfield, Kenneth S. Campbell
Physiology Faculty Publications
A skeletal muscle fiber that is stimulated to contract and then stretched from L₁ to L₂ produces more force after the initial transient decays than if it is stimulated at L₂. This behavior has been well studied experimentally, and is known as residual force enhancement. The underlying mechanism remains controversial. We hypothesized that residual force enhancement could reflect mechanical interactions between heterogeneous half-sarcomeres. To test this hypothesis, we subjected a computational model of interacting heterogeneous half-sarcomeres to the same activation and stretch protocols that produce residual force enhancement in real preparations. Following a transient period of elevated force associated with …
Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell
Interactions Between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior In A Mathematical Model Of Muscle, Kenneth S. Campbell
Physiology Faculty Publications
Most reductionist theories of muscle attribute a fiber's mechanical properties to the scaled behavior of a single half-sarcomere. Mathematical models of this type can explain many of the known mechanical properties of muscle but have to incorporate a passive mechanical component that becomes approximately 300% stiffer in activating conditions to reproduce the force response elicited by stretching a fast mammalian muscle fiber. The available experimental data suggests that titin filaments, which are the mostly likely source of the passive component, become at most approximately 30% stiffer in saturating Ca2+ solutions. The work described in this manuscript used computer modeling to …