Very low force-generating ability and unusually high temperature-dependency in hummingbird flight muscle fibers

Very low force-generating ability and unusually high temperature dependency in hummingbird flight muscle fibers.

Hummingbird flight muscle is estimated to have among the highest mass-specific power output among vertebrates, based on aerodynamic models. However, little is known about the fundamental contractile properties of their remarkable flight muscles. We hypothesized that hummingbird pectoralis fibers generate relatively low force when activated in a tradeoff for high shortening speeds associated wit...

Hummingbird flight

Hummingbirds are very distinctive in their form and behavior, the evolution of which is tightly connected to the evolution of their primary source of energy - floral nectar. About forty million years ago, the practical use of this dense fuel, available only in widely-dispersed, insect-sized aliquots - it was originally intended for insect pollinators - presented a severe test to the avian baupl...

Morphological and kinematic basis of the hummingbird flight stroke: scaling of flight muscle transmission ratio.

Hummingbirds (Trochilidae) are widely known for their insect-like flight strokes characterized by high wing beat frequency, small muscle strains and a highly supinated wing orientation during upstroke that allows for lift production in both halves of the stroke cycle. Here, we show that hummingbirds achieve these functional traits within the limits imposed by a vertebrate endoskeleton and muscl...

The Aerodynamics of Hummingbird Flight

Temperature dependency of force loss and Ca homeostasis in mouse EDL muscle after eccentric contractions

Warren, Gordon L., Christopher P. Ingalls, and R. B. Armstrong. Temperature dependency of force loss and Ca2 homeostasis in mouse EDL muscle after eccentric contractions. Am J Physiol Regulatory Integrative Comp Physiol 282: R1122–R1132, 2002. First published December 21, 2001; 10.1152/ajpregu.00671.2001.—The goals of this study were first to determine the effect of temperature on the force los...