Research Focus: Biomechanics and Neural Control of the Musculoskeletal System, Focusing on the Human Head and Neck System
The Gene and Linda Voiland
School of Chemical Engineering and Bioengineering
1505 Stadium Way, Room 105
P.O. Box 646515
Washington State University
Pullman, WA 99164-6515
Office: G5 Wegner Hall (Tel: 509-335-7533)
Lab: McCoy South 206 & 210 (Tel: 509-335-7793)
Biomechanics 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, addressing areas such as ergonomics, concussion, whiplash injury and gender differences in neck biomechanics. My goal is to apply the knowledge gained from modeling and experiments to improve the prevention, diagnosis and treatment of neck musculoskeletal disorders.
Specific Research Projects
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.
Dr. Vasavada received a B.A. in Mathematics/Physics from Whitman College and a B.S. in Mechanical Engineering from Columbia University in 1990. She received an M.S. in Mechanical Engineering from Stanford University in 1991. From 1991 to 1993, she worked as an engineer in the Biomechanics Laboratory in the Department of Orthopedics and Rehabilitation at Yale University. She received a Ph.D. in Biomedical Engineering from Northwestern University in 1999. After graduation, Dr. Vasavada was a postdoctoral fellow in the Department of Neurology at Emory University. In January 2001, she joined the faculty of Washington State University as an assistant professor in the departments of VCAPP and Bioengineering.
- Hildenbrand, K, Nevins, D, Vasavada, A, Smith, L. On-field head impact exposure in adolescent boys soccer measured by head-mounted accelerometers. Annals of Biomedical Engineering, in review, 2015.
- Vasavada, AN, Nevins, DD, Monda, SM, Hughes, E, Lin, DC. Gravitational Demand on the Neck Musculature during Tablet Computer Use. Ergonomics, in press, 2015.
- Nevins DD, Zheng, L, Vasavada, AN. Inter-individual Variation in Vertebral Kinematics Affects Predictions of Neck Musculoskeletal Models. Journal of Biomechanics, in press, 2015.
- Lin, D., Godbout, D., Vasavada, AN. Assessing the perception of human-like mechanical impedance for robotic systems. IEEE Transactions on Human-Machine Systems, 43(5), 479-486, 2013.
- Hildenbrand, K, Vasavada, AN. Collegiate and high school athlete neck strength in neutral and rotated postures. Journal of Strength and Conditioning Research, 27(11):3173-82, 2013.
- Zheng, L, Siegmund, GP, Ozyigit, G, Vasavada, AN. Sex-specific prediction of neck muscle volumes. Journal of Biomechanics, 46:899-904, 2013.
- Zheng L, Jahn J, Vasavada, AN. Sagittal plane kinematics of the adult hyoid bone. Journal of Biomechanics, 45:531-536, 2012.
- Suderman, BL, Vasavada, AN. Moving muscle points provide accurate curved muscle paths in a model of the cervical spine. Journal of Biomechanics, 45:400-404, 2012.
- Suderman, BL, Krishnamoorthy, B, Vasavada, AN. Neck muscle paths and moment arms are significantly affected by wrapping surface parameters. Computer Methods in Biomechanics and Biomedical Engineering, 15:7:735-744, 2012.
- Jahn J, McMulkin ML, Vasavada, AN. Calf muscle-tendon lengths before and after Tendo-Achilles lengthenings and gastrocnemius lengthenings for equinus in cerebral palsy and idiopathic toe-walking. Gait and Posture, 29(4):612-617, 2009.
- Hicks, DH, Pitts, MJ, Bagley, RS, Vasavada, A, Simon, J, Chen, AV, Wininger, FA. In vitrobiomechanical evaluation of a novel internal fixation implant and a traditional pin with polymethylmethacrylate internal fixation implant used to stablize the C4 – 5 vertebral motion unit in canine cervical spines. American Journal of Veterinary Research, 70(6)719-26, 2009.
- Vasavada, AN, Lasher, RA, Meyer, TE, Lin, DC. Defining and evaluating MRI-derived wrapping surfaces for spinal muscles. Journal of Biomechanics, 41:1450-1457, 2008.
- Vasavada, AN, Danaraj, J, Siegmund, GP. Head and neck anthropometry, vertebral geometry and neck strength in height-matched men and women. Journal of Biomechanics, 41:114-121, 2008.
- Vasavada, AN, Brault, JR, Siegmund, GP. Musculotendon and fascicle strains in anterior and posterior neck muscles during whiplash injury. Spine, 32(7):756-765, 2007.
- Anderson, J, Hsu, A, Vasavada, AN. Morphology, architecture and biomechanics of the human cervical multifidus. Spine, 30:4:E86-E91, 2005.
- Vasavada, AN, Peterson, BW, Delp, SL. Three-dimensional spatial tuning of neck muscle activations in humans. Experimental Brain Research, 147:4:437-448, 2002.
- Panjabi, MM, Crisco, JJ, Vasavada, A, Oda, T, Cholewicki, J, Nibu, K, Shin, E. Mechanical properties of the human cervical spine as shown by three-dimensional load-displacement curves. Spine, 26(24):2692-2700, 2001.
- Vasavada, AN, , Li, S, Delp, SL. Three-dimensional isometric strength of neck muscles in humans. Spine, 26(17):1904-1909, 2001.
- Vasavada, AN, Li, S, Delp SL. Influence of muscle morphometry and moment arms on the moment-generating capacity of human neck muscles. Spine, 23(4):412-422, 1998.