Biomechanics and Control of Agile Locomotion: from Walking to Jumping (Talk)

Animals seem to effortlessly navigate complex terrain. This is in stark contrast with even the most advanced robot, illustrating that navigating complex terrain is by no means trivial. Humans’ neuromusculoskeletal system is equipped with two key mechanisms that allow us to recover from unexpected perturbations: muscle intrinsic properties and sensory-driven feedback control. We used unique in vivo and in situ approaches to explore how guinea fowl (Numida meleagris) integrate these two mechanisms to maintain robust locomotion. For example, our work showed a modular task-level control of leg length and leg angular trajectory during navigating speed perturbations while walking, with different neuromechanical control and perturbation sensitivity in each actuation mode. We also discovered gait-specific control mechanisms in walking and running over obstacles. Additionally, by combining in vivo and in situ experimental approaches, we found that guinea fowl LG muscles do not operate at optimal muscle lengths during force production during walking and running, providing a safety factor to potential unexpected perturbations. Lastly, we will also highlight some work showing how kangaroo rats circumvent mechanical limitations of skeletal muscles to jump as well as how these animals overcome angular momentum limitations during aerial reorientation during predator escape leaps. Elucidating frameworks of functions, adaptability, and individual variation across neuromuscular systems will provide a stepping-stone for understanding fundamental muscle mechanics, sensory feedback, and neuromuscular health. Additionally, this research has the potential to reveal the functional significance of individual morphological, physiological, and neuromuscular variation in relation to locomotion. This knowledge can subsequently inform individualized rehabilitation approaches and treatment of neuromuscular conditions, such as stroke-related motor impairments, as they require an integrated understanding of dynamic interactions between musculoskeletal mechanics and sensorimotor control. This work also provides foundational knowledge for the development of dynamic assistive devices and robots that can navigate through complex terrains.