This contrasts with nature's most extreme case of repetitive muscle action, the high frequency flight muscles of bees and other insects, which contract multiple times in response to a single impulse. (sciencedaily.com)
He adds that human heart muscle works in much the same way as flight muscle, and this work could eventually give insight into why hearts fail. (sciencemag.org)
Archaeopteryx doesn't have several features considered essential to flight in modern birds, such as a keeled breastbone to which several important flight muscles attach; a ball - and - socket arrangement that allows the wing to flap fully up over the back and down again; and a muscle pulley system that links chest and shoulder muscles, allowing the birds to swiftly alternate between powerful downstrokes and upstrokes. (sciencenews.org)