Dr. Gay's primary research interests include biomechanics of the lumbar spine (particularly reaction the effects loading and off-loading stresses on the intervertebral discs), the biomechanical and physiologic effects of spinal manipulation, and the non-surgical treatment of low back and neck pain. He was awarded an Academic Career Award from the National Center for Complementary and Alternative Medicine (NIH AT00972). His master's thesis (MS Clinical Research) quantified the effect of axial distraction of the lumbar spine (with flexion or with extension) on stress distribution in lumbar discs. Dr. Gay directs the Spine Biomechanics Research Group in the Biomechanics Laboratory (Division of Orthopedic Research). Active or recent projects include:

• The reliability of intradiscal stress profilometry in cadaveric lumbar discs. Gay RE, Zhao KD, Ilharreborde B, Bridges J, An KN.

• Stress profiles of the lumbar intervertebral discs during axial distraction with flexion, and axial distraction with extension. Gay RE, Bronfort G, An K.
• The effect of freeze-thaw cycles on the biomechanical properties of human cadaveric motion segments. Gay RE, Hongo, M, Berglund L, An K.
• The effect of loading rate on dynamic motion parameters in the lumbar spine. Gay RE, Ilharreborde B, Zhao K, Zhao C, An K.
• Adjacent segment response after lumbar fusion: a dynamic in vitro study of kinematics and nucleus pressure. Ilharreborde B, Gay RE, Zhao, KD, Boumediene E, An KN.
• Comparison of cervical mobilization and physical therapy for chronic neck pain: a feasibility study. Madson T, Gay RE, Cieslak, K.
• Comparison of the Neck Disability Questionnaire and the Neck Bournemouth Questionnaire in patients with chronic, uncomplicated neck pain. Madson T, Gay RE, Cieslak K.
• Biomechanical evaluation of a novel clamp fixation device in human lumbar and thoracic vertebrae: A cadaver study. Hongo M, Gay R, Zhao K, An KN.
• A cadaver study of effects of supplemental instrumentation for rigid lumbar arthrodesis on adjacent segment motion: A biomechanical comparative study. Hongo M, Dekutoski M, Gay R, Huddleston P, Zhao C, Zhao K.