Metabolic Projects
Robin L. Marcus, PT, PhD, OCS is a faculty member in the Department of Physical Therapy at the University of Utah and an active researcher and clinician in the SMERF. She is a board certified orthopedic clinical specialist whose clinical interests revolve around individuals with musculoskeletal dysfunction and muscle weakness. Dr. Marcus is currently a BIRCWH Scholar with the Department of Obstetrics and Gynecology at the University of Utah . This mentored research award is funded by The Office for Research on Women's Health, National Institutes of Health, Bethesda , MD. Dr. Marcus' general research interests are in the plasticity of skeletal muscle and how it responds to mechanical stress.
Research Focus
It has been suggested that men and women, especially older men and women respond differently to resistance training. Dr. Marcus is specifically interested in these sex differences with respect to muscle hypertrophy and its related outcomes, i.e. muscle structure, function, and metabolism.
Sarcopenia is a loss of muscle size and strength associated with aging that negatively impacts functional performance. Decreased muscle size is also linked with resistance to the actions of insulin, a major factor leading to high blood glucose (sugar) levels and poor glucose control. Strength training that produces high muscle forces that result in improved muscle size and strength can improve functional performance as well as the body's sensitivity to the actions of insulin. The populations of interest include both older and younger individuals with muscle atrophy who may benefit, both functionally and metabolically from improved muscle mass.
Current Projects
Currently, Dr. Marcus is investigating the impact of high force resistance training in post-menopausal females with impaired glucose tolerance and on older individuals with Type 2 Diabetes. The long term goal is to optimize resistance exercise prescription to result in the maximum health and function of women across the lifespan. The research aims are 2-fold; to determine the impact of high force resistance training: 1) on muscle structure and functional performance, and 2) on the actions of insulin. In addition, Dr. Marcus is interested in identifying potential mechanisms for these aims and whether these mechanisms differ with respect to sex, age, and initial level of atrophy. Recent findings suggest a role for insulin-like growth factor-1 (IGF-1) and mitochondrial content and function as potential mechanisms for how this type of exercise affects skeletal muscle. The evaluation methods used to achieve these aims include muscle imaging (MRI), muscle biopsy (histologic and biochemical tissue analyses), strength and functional performance battery (isometric force, TUG, 6 minute walk, stair ascent / descent), oral glucose tolerance tests, glucose clamp tests, and PET scanning (leg glucose uptake). A novel form of resistance training, eccentric ergometry, is our experimental model of muscle hypertrophy. Because eccentric exercise produces high muscle forces and requires much less energy than aerobic or traditional strength training, it provides a strong stimulus for muscle growth, while being more easily tolerated by individuals who may traditionally be considered exercise intolerant.
Collaborators
Lee Dibble, PT, PhD, ATC
Associate Professor, Department of Physical Therapy
University of Utah
Paul LaStayo, PT, PhD, CHT
Associate Professor, Department of Physical Therapy
Director, SMERF, University of Utah
Don McClain, MD, PhD (BIRCWH Mentor)
Professor, Department of Internal Medicine
Chief, U of U Division of Endocrinology & Metabolism
Daniel P. Williams, PhD
Exercise and Sport Science
University of Utah
