Room: Wegner 209
ResearchBiomechanics and neural control of the musculoskeletal system, utilizing anatomically-based models complemented with experimental data. Most of my research is focused on the human head and neck system.
Ergonomics of Mobile Devices
Forward or flexed head posture occurs frequently while using mobile devices and are implicated in neck pain, although the mechanisms are not well understood. We have quantified the increase in head and neck flexion and musculoskeletal load while subjects used tablet computers in different conditions (with and without a desk; with and without an accessory stand). We calculated gravitational demand, a measure of load required by neck muscles to hold up the head, which is related to increased soft tissue loads on other neck structures (e.g., facet joints, intervertebral discs) and neck muscle fatigue. We found that gravitational demand in tablet usage conditions increased 3-5 times the gravitational demand in neutral posture.
Postural stability of the human head and neck
Neck muscles are important for both static postural stability (i.e., holding up the head) and restoring head posture under dynamic conditions, such as those that might occur during a blow to the head or an automobile accident (e.g., whiplash injury). When muscles are unable to stabilize the head, it can lead to injury and chronic neck pain. We are examining how the activation of neck muscles complements passive tissue stiffness to achieve postural stability using experimental studies in human subjects integrated with biomechanical model analysis.
Mechanisms of whiplash injury
The anatomical site and mechanism of injury during whiplash (a rapid acceleration of the head and neck) are still unclear. We have utilized a biomechanical model of the neck musculoskeletal system with experimental data of human subjects undergoing 5 mph whiplash-like perturbations to calculate the strains, and thus potential for injury, in neck muscles.
Gender differences in the neck musculoskeletal system
The goal of this work is to evaluate factors responsible for the increased incidence of whiplash injury and neck pain in females vs. males. We have found that female neck geometry is not a simple scaled version of male neck geometry, which implies that gender-specific biomechanical models are necessary to evaluate gender differences in neck musculoskeletal disorders. We are currently developing a biomechanical model of the female neck musculoskeletal system.
Improving the geometric representations of neck muscles in biomechanical models
Our current models of the neck musculature represent neck muscles as straight lines. We are incorporating curved muscle paths into our models by defining geometrical constraints that approximate the curved neck muscle paths based on magnetic resonance imaging (MRI) data.
- Vasavada AN, Nevins DD, Monda SM, Hughes E, Lin DC (2015) Gravitational Demand on the Neck Musculature during Tablet Computer Use Ergonomics 58(6), 990-1004 PMID: 25643042 PMCID:
- Hildenbrand K, Nevins D, Vasavada A, Smith L (2015) On-field head impact exposure in adolescent boys soccer measured by head-mounted accelerometers Annals of Biomedical Engineering PMID: PMCID:
- Nevins DD, Zheng L, Vasavada AN (2015) Inter-individual Variation in Vertebral Kinematics Affects Predictions of Neck Musculoskeletal Models J Biomech 47(13), 3288-94 PMID: 25234351 PMCID: PMC4203672
- Lin DC, Godbout D, Vasavada AN (2013) Assessing the perception of human-like mechanical impedance for robotic systems IEEE Transactions on Human-Machine Systems 43(5), 479-486 PMID: PMCID:
- Hildenbrand KJ, Vasavada AN (2013) Collegiate and high school athlete neck strength in neutral and rotated postures J Strength Cond Res 27(11), 3173-82 PMID: 23439331 PMCID:
- Zheng L, Siegmund G, Ozyigit G, Vasavada A (2013) Sex-specific prediction of neck muscle volumes J Biomech 46(5), 899-904 PMID: 23351366 PMCID: PMC3648672
- Zheng L, Jahn J, Vasavada AN (2012) Sagittal plane kinematics of the adult hyoid bone J Biomech 45(3), 531-6 PMID: 22176712 PMCID: PMC3295612
- Suderman BL, Vasavada AN (2012) Moving muscle points provide accurate curved muscle paths in a model of the cervical spine J Biomech 45(2), 400-4 PMID: 22033046 PMCID:
- Suderman BL, Krishnamoorthy B, Vasavada AN (2012) Neck muscle paths and moment arms are significantly affected by wrapping surface parameters Comput Methods Biomech Biomed Engin 15(7), 735-44 PMID: 21416413 PMCID:
- Jahn J, Vasavada AN, McMulkin ML (2009) Calf muscle-tendon lengths before and after Tendo-Achilles lengthenings and gastrocnemius lengthenings for equinus in cerebral palsy and idiopathic toe-walking Gait Posture 29(4), 612-7 PMID: 19200730 PMCID: