Dr. Hollerbach is an Associate Scientist at NDRI-USA and SSIC.

She received her Ph.D. in Exercise Science from Kansas State University and completed a postdoctoral research fellowship at Skidmore College under the direction of Dr. Denise Smith where she focused on cardiovascular disease in the fire service.

She is Tactical Strength & Conditioning Facilitator (TSAC-F) certified through the National Strength and Conditioning Association.

Dr. Hollerbach has extensive experience working with the fire service on a number of federally funded firefighter studies. She has contributed to the validation of fire department physical ability tests and has extensive experience as a Candidate Physical Ability Test proctor.

Dr. Hollerbach has an interest in firefighter health in general and physical fitness and health specifically, given her background as a former firefighter and fire training instructor.

Dr. Haddock completed graduate work in Clinical Psychology and Statistics and Research Methodology from the University of Memphis, Applied Statistics at the Pennsylvania State University, and Data Science and Business Intelligence at Rockhurst University.

Dr. Haddock is an Accredited Professional Statistician (PStat®) with the American Statistical Association and a Fellow with The Obesity Society (FTOS).

Dr. Haddock has published over 230 scientific articles, primarily focusing on first responder, military, and veteran's issues. He is also a decorated military veteran, having served in the U.S. Air Force on active duty and as an active Reserve officer.

Much of Dr. Haddock’s scientific career has focused on improving the health of our nation’s first responders including the military and the fire service.

Dr. Poston is the CEO and a Senior Scientist at NDRI-USA and SSIC.

As a scientist with a family history in both the fire service and the military, he has a passion for addressing health issues among first responders.

Dr. Poston has graduate degrees in the behavioral sciences (University of California, Santa Barbara) and epidemiology (University of Texas Houston Health Science Center, School of Public Health). He completed postdoctoral fellowships in Behavioral Health Psychology (Wilford Hall Medical Center) and in Cardiovascular Health (American Hospital Association Health Forum). His research focuses primarily in the areas of obesity, physical activity, cardiovascular disease prevention with an emphasis on minority populations, and military and first-responder health.

He has been a principal investigator or co-investigator on several firefighter physical ability test projects.

Maria Koeppel is an Associate Research Scientist at the Center for Fire, Rescue, and EMS Health Research at NDRI-USA, where she leads federally funded projects focused on improving the health, wellness, and culture of first responders. She serves as Principal Investigator on a National Institutes of Health study examining alcohol use among EMS providers and a Department of Homeland Security/FEMA grant aimed at advancing inclusion within the fire service. Her broader portfolio includes national research on occupational health, cancer risk, behavioral health, and disaster response.

Before transitioning into fire and EMS research, Maria's academic training was in criminal justice and corrections, earning a Ph.D. in Criminal Justice and publishing extensively on victimization, health consequences of trauma, gender, and correctional systems. This earlier work strengthens her applied approach to studying workforce health and organizational risk. She regularly presents her research at national conferences and has authored peer-reviewed publications, technical reports, and practitioner-focused resources that translate science into practice. In addition to her research, Maria continues to serve as a firefighter/EMT, ensuring her work remains grounded in the realities of emergency response.