Dr. Gao's research is focused on biomechanics of musculoskeletal soft tissues, including skeletal muscles, ligaments and tendons. Soft tissues have similar ultrastructures with engineering materials, such as polymers. Therefore, mechanical theories can be applied to soft tissues to evaluate the structure function relationship. However, different than the engineering materials, internal structure of these biological tissues will be changed as a response to an altered biological and/or mechanical environment. Dr. Gao is interested in determining: (1) the structure function relationship of the tissues; (2) the molecular, structural and functional changes induced by diseases, injuries and aging; (3) the underlying mechanisms of these changes; (4) the effect of external mechanical loading on the these adaptive changes. The multidisciplinary work involves techniques and knowledge in biomechanics, biochemistry and cell biology.

Dr. Gao's research group also focuses on biomechanics of shoulder joint. Shoulder joint, also called glenohumeral joint, is the most anatomically and mechanically complicated joint in human body. It is characterize by large range of motion and high instability. Dr. Gao is currently interested in determining important surgical, anatomical and implant design factors that affect the performance of total shoulder implants. The work involves both computational and experimental approaches.

Current Projects

• Analysis of glenoid loosening of total shoulder implant
  Total shoulder replacement has been established as an effective procedure for degenerative arthropathy of the glenohumeral joint. One of the major concerns is mechanical loosening of the glenoid component. The goal of this project is to identify the surgical, design and anatomical factors that affect the short term and long term results of the total shoulder replacement. In collaborating with the Biomechanics Lab in the Hospital for Special Surgery (HSS), we will use specimen specific 3D finite element models (FEMs) developed using CT scan data from the cadaver shoulders to analyze the stress and strain distribution in the scapula and the glenoid component.
   
• Rotator cuff muscle response to rotator cuff tears
  Rotator cuff tears are common orthopedic problems. The tears may be associated with pain and severe functional impairment. Rotator cuff repair is a successful procedure with regard to pain relief and functional outcome. Muscle atrophy and fatty degeneration are important factors that affect the outcome of treatment. Some of changes are not reversible. The overall goal of this study is to determine the molecular, structural and functional changes after rotator cuff tears, and understand the mechanisms of atrophy and fatty degeneration of rotator cuff muscle after rotator cuff tear. The effect of mechanical loading on muscle degeneration and regeneration will also be investigated.
   
• Anterior Cruciate Ligament (ACL) injury
  The rate of female soccer ACL injuries has been reported to be 4 and 8 times of male soccer ACL injuries. We will use a training room setup of ultrasound measurement of the area and location of the ACL to detect changes weekly in women soccer team, and instrument the athlete recording the amplitude and frequency of shocks across the knee joint accounting between the femur and the tibia.  The relationship between the event history, rest period and the area/location will be established.  

• The role of extracellular matrix (ECM) on active and passive mechanical properties of skeletal muscle
  The extracellular matrix (ECM) of the skeletal muscle provides a framework for the structural support of the capillaries and nerves.  It is also an essential component in force generation and transmission in the skeletal muscle. In this project, we will determine the role of the ECM in passive and active mechanical properties of the skeletal muscle, and investigate the aging effect on the mechanical properties of the ECM. A finite element model will be developed to establish the structure function relationship of the ECM.

 

 

Position Announcements

We currently have multiple positions at different level. Interested students please click here

Yingxin Gao Bachelor of Science, Huazhong University of Science and Technology, China, Power Engineering, 1999 Master of Science, University of Delaware, Mechanical Engineering, 2003 Ph.D., University of Michigan, Mechanical Engineering, 2007 Email: yg75@cornell.edu

SELECTED PUBLICATIONS Gao Y., Faulkner JA., Kostrominova T., Wineman A.S., "Age related changes in the mechanical properties of the epimysium in skeletal muscles of rats," J Biomechanics, 2008, 41(2), 465-469. Gao Y.,Wineman A.S., Waas A.M.,"Mechanics of the muscle injury induced by eccentric contraction”, Annals of Biomedical Engineering, accepted. Gao Y., Waas A.M., Faulkner J.A., Kostrominova T., Wineman A.S., "Micromechanical modeling of the epimysium of the skeletal muscles", J Biomechanics 2008, 41(1), 1-10. Gao Y., Waas A.M., Faulkner J.A., Wineman A.S., "Mechanics of injury to muscle fibers ," Journal of Mechanics in Medicine and Biology, 2007, 7(4), 381-394