Muscles as tunable springs: from molecular mechanisms to animal movement 

Muscles are highly adaptable, versatile materials but the molecular mechanisms underlying these properties are not well understood. Several lines of evidence suggest that the giant sarcomeric protein, titin functions as a tunable spring in active muscle. Results from ex vivo muscle experiments on mutant mouse muscles support the hypothesis that titin binds to actin in the presence of calcium, which decreases its equilibrium length and increases its stiffness. The tunable viscoelastic properties of titin can explain many elusive muscle properties such as the increased force during eccentric contractions and muscle force during dynamic length changes. These findings have the potential to improve traditional models of muscle contraction based solely on the sliding-filament, swinging cross-bridge theories and inspire the design of “muscle-like” actuators that emulate the inherent adaptability required for all-terrain locomotion.

Dr. Jenna Monroy