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Jennifer A. Schrack, PhD

Core Faculty, Center on Aging and Health

Associate Faculty, Welch Center for Prevention, Epidemiology and Clinical Research

Assistant Professor

Departmental Affiliation(s):


Center & Institute Affiliation(s):

Contact Information

615 N. Wolfe Street
Room E6137
Baltimore , Maryland   21205



PhD , BSPH , 2011
MS , University of Michigan , 2002


My primary area of research is the analytical study of physical activity energy expenditure and functional decline in older populations through the assessment of: (i) the complex interaction between energy expenditure and gait speed decline and (ii) objectively measured physical activity patterns and trends. 

Physical activity energy expenditure is a modifiable risk factor for functional decline in older populations. Through the use of accelerometers, we now have incredible opportunities to better understand daily activity patterns and trends with an unprecedented level of detail. Such technologies use less biased, silent observers, such as heart rate monitors and hip accelerometers that will ultimately transform epidemiological research and have the potential to be widely used in the implementation of prevention.  In collaboration with the SMART group ( from the JHSPH department of biostatistics, I am working to develop new methodology to analyze and translate heart rate and accelerometry data into accurate and reliable measures of physical activity in older populations.  This work is crucial to understanding changes in energy expenditure and physical function with age and for managing and treating chronic conditions in older adults. 

Honors and Awards


2013 - 2014 Johns Hopkins Center for AIDS Research Faculty Development Award

2011 - 2012 National Institute on Aging Postdoctoral Fellowship

2007 – 2011 National Institute on Aging Epidemiology and Biostatistics of Aging Training Grant Fellow, Johns Hopkins Bloomberg School of Public Health


    Selected publications

  • Schrack JA, Knuth ND, Simonsick EM, Ferrucci L.  “IDEAL” aging is associated with lower resting metabolic rate: the Baltimore Longitudinal Study of Aging. Journal of the American Geriatrics Society, In Press.

  • Schrack JA, Zipunnikov V, Goldsmith AJ, Crainiceanu CM, Simonsick EM, Ferrucci L.  Assessing the “Physical Cliff”: Detailed Quantification of Physical Activity and Aging. J Gerontol Med Sci 2013 Dec; epub ahead of print.

  • Schrack JA, Simonsick EM, Chaves PHM, Ferrucci L. The Role of Energetic Cost in Gait Speed Decline. Journal of the American Geriatrics Society. 2012 Oct;60(10):1811.

  • Schrack JA, Simonsick EM, Ferrucci L. The Relationship of the Energetic Cost of Slow Walking and Peak Energy Expenditure to Gait Speed in Mid-to-Late Life.  American Journal of Physical Medicine and Rehabilitation 2012 Jul 30.

  • Schrack JA, Simonsick EM, Ferrucci L.  The Energetic Pathway to Mobility Loss: An Emerging New Framework for Longitudinal Studies on Aging. Journal of the American Geriatrics Society.  2010 Oct 1;58:S329.