Physical Activity Core
High-quality nutrition and physical activity are fundamental in optimal growth and development. Correspondingly, suboptimal nutrition and exercise are causative factors in the development of obesity, and improvement of these factors are vital for the reversal of obesity and its related disturbances in metabolism. There are both independent and synergistic effects of nutrition and physical activity on metabolism and growth. The ACNC Physical Activity Core was established in 2013 to support ACNC investigators conduct studies of physical activity and exercise in growth and development. The core includes a 3,000-ft2 Fitness Facility for controlled exercise training studies and a ~1400 ft2 Laboratory for Active Kids and Families which is a fully-equipped pediatric exercise test laboratory.
The Fitness Facility is outfitted with four treadmills, four recumbent bikes, and four elliptical machines, in addition to easily adjustable equipment for resistance exercise that facilitates studies in pregnant women and in children. Intensity can be closely monitored through heart rate monitors. The facility also has floor space for free play, directed activities and class activities. Step benches, medicine balls, free weights, smaller gym equipment and mats are also available.
The Laboratory for Active Kids and Families contains all the equipment needed for comprehensive fitness and metabolic phenotyping in children and adults. This includes two metabolic carts for indirect calorimetry during exercise and resting conditions, pulmonary function testing unit, two treadmills, adult and pediatric test bikes, a dynamometer for testing of various components of muscle strength, equipment for balance testing and equipment for flexibility testing.
Elisabet Borsheim, Ph.D., Core Director
Eva Diaz, M.D., MMSc, Instructor
Alvin Dupens III, BS, Exercise Trainer
Timothy J. Edwards, MS, Exercise Physiologist
Catarina Young, BS, Research Assistant
Cardiorespiratory/aerobic fitness is an important predictor of metabolic health. A person’s maximal or peak oxygen uptake is a demonstration of their aerobic fitness. We are measuring this using indirect calorimetry (Ultima PFX Cardio 2, MedGraphics) in children and adults while the volunteer is exercising using large muscle groups on a treadmill or bike. The indirect calorimetry system is also used for submaximal exercise tests and for resting measurements.
As one of the components of physical fitness, muscle strength is important for physical function and health in humans. We use a dynamometer (Humac Norm, CSMi) to assess various components of muscular force (concentric, eccentric, isometric, isokinetic etc). The system enables isolation and testing of various muscle groups. Further, we use a hydraulic hand dynamometer (Jamar) to test handgrip strength.
We use a computerized system for balance testing (Humac Balance, CSMi), enabling various balance tests like limits of stability, random motion, weight shift etc.
We typically test flexibility with a sit-and reach test (Lafayette Instruments) in children. Other manual tests can be performed, depending on the study needs.
We use spirometry to test lung function (Ultima PFX, MedGraphics), e.g., forced vital capacity, forced expiratory volume in one second, peak expiratory flow, etc. The core can also determine lung diffusion capacity to assess how easy oxygen diffuses from the lung into the blood.
Description of Some Projects Supported by the Core
Based on data collected at ACNC, children of obese mothers may be predisposed to obesity. In one of the ongoing studies supported by the Core, children born to lean, overweight or obese mothers are tested for endurance and strength in the laboratory as part of detailed phenotyping.
The aim of the Expecting study is to determine if exercise training through the pregnancy can attenuate negative effects of obesity on the mothers and their babies. Obese sedentary women are randomized to standard of care or exercise training during pregnancy. The women in the exercise group come to the Fitness Facility three times per week for aerobic and resistance training under direction of a trainer. They are tested for fitness in the Laboratory for Active Kids and Families before and after three months of training.
As the rates of pediatric obesity in Arkansas are among the highest in the US, the Laboratory for Active Kids and Families supports studies to determine underlying mechanisms. In a USDA/ARS-funded study, children go through a battery of exercise tests combined with assessment of other metabolic variables to determine the independent impact of weight status, physical activity and physical fitness, respectively, on overall cardiometabolic health. The study is also aiming for identifying household, environmental, and socio-demographic factors associated with weight status and metabolic health.