UC Irvine

Most legged animals have evolved a suite of musculoskeletal adaptations to reduce the energetic cost of locomotion (e.g. upright limb posture, long tendons), but it remains unclear whether alligators and other sprawlers are capable of using similar energy saving mechanisms during locomotion. Through a combination of in situ muscle preparations, joint-level analyses, and in vivo muscle function measurements during walking we show that 1) alligator limb joint mechanics are similar to other legged animals during walking, 2) a representative ankle extensor, the gastrocnemius externus, is capable of storing significant elastic energy in its tendon during supramaximal contractions, 3) in vivo muscle work during locomotion is surprisingly low, suggesting tendon does significant work during locomotion, and 4) alligators modulate limb and limb muscle function to improve stability or work generation when walking across non-level terrain. This work adds to the body of work on muscle function during legged locomotion and shows that general strategies and energy saving mechanisms (e.g. elastic energy storage) during legged locomotion are likely more widespread than previously assumed.