The HuMBL Lab pairs measurements of of human motion with musculoskeletal models to understand how the underlying structures contribute to the observed motion, whether through active neuromuscular control, or passive dynamics. We primarily use rigid multibody simulators such as OpenSim, but we also utilize finite element and hybrid simulations (such as ArtiSynth) for more detailed analyses. We also perform experiments to collect tissue mechanical properties to develop these models. Here, we are primarily interested in material changes at high strain rates.
Currently, we are interested in studying knee and ankle ligament injuries and developing better tools to study high strain rate tissue mechanics.
The neck plays a pivotal role in dictating how the head responds to a direct impact. The neck skeletal structure provides both a kinematic constraint for the head and the neck soft tissue structures provide active and passive stability.
To study the role of the neck in stabilizing the head during impacts, we applied mild head loads to human participants and measured the resulting kinematics in response to loads in different directions and with different muscle activation levels. Our first finding showed that the resulting head kinematics varied most with loading direction due to differences in how the cervical spine constrained the heads motion in different directions.
To study the soft tissue contribution to head stability during impacts, we developed a musculoskeletal model of the head and neck with added ligaments in OpenSim. The ligament material properties were designed to have a dependence on strain rate, as has been observed experimentally.
We found here that while the active musculature play a role in stabilizing the head during mild loads, the ligaments are the primary stabilizers in higher severity impacts, such as median American football impacts. Together, we suggest that it is not increasing neck muscle strength that matters most in stabilizing the head during impacts, but taking advantage of the skeletal constraint by controlling the direction of impact loads.
All of our experimental data and models for this project are provided through our OpenSim page.
Kuo C, Fanton M, Wu L, Camarillo D. Spinal constraint modulates head instantaneous center of rotation and dictates head angular motion. Journal of biomechanics. 2018 Jul 25;76:220-8. Link.
Kuo C, Sheffels J, Fanton M, Yu IB, Hamalainen R, Camarillo D. Passive cervical spine ligaments provide stability during head impacts. Journal of the Royal Society Interface. 2019 May 31;16(154):20190086. Link.