Physical activity is essential to prevent and treat childhood obesity, and plays an important role in the development of healthy joint function in normal weight children. Considering a greater prevalence of lower extremity malalignment in obese children, the extent to which excess adiposity, functional disabilities and abnormal gait impact the ability of this population to engage in physical activity and promote long-term musculoskeletal function and health is not yet understood. The objective of this proposal is to determine how obesity and lower extremity joint alignment affect the biomechanics (hip and knee joint contact forces) of walking and running in children. The central hypothesis is that obesity and walk/run duration negatively affect walking and running hip and knee joint loads. The rationale for the proposed research is that by quantifying walk/run hip and knee joint contact forces in obese children, we can evaluate the risk of musculoskeletal injury/pathology during these common forms of movement, allowing the development of effective weight- bearing physical activity prescriptions in the children who need it most.
The first aim of this study is to determine the relationship between obesity, lower extremity alignment and hip and knee joint loading environment during walking/running in children. This will be accomplished by using musculoskeletal simulations to determine the joint loading environment during walking and running in obese and non-obese children. To establish the relationship between the joint loading environment during walking/running and osteoarticular alterations in obese children, the degree of lower extremity malalignment, determined through radiographic images, will be correlated with subject-specific joint contact force estimates.
The second aim of this study is to determine how activity duration affects lower extremity joint loads and muscle forces during sustained bouts of walking and running in obese and non-obese children. By using the same musculoskeletal models developed for Aim 1, and completing similar simulations to determine joint loads and muscle forces at set intervals during prolonged walking and running, it will be possible to quantify the duration at which increased risk to the musculoskeletal system may occur in obese children. An automated treadmill controller will be used to quantity how locomotor speeds change during continuous bouts of walking and running. This project strives to better understand the connection between obesity, exercise duration, mechanical loading environment and musculoskeletal health in children. The outcomes of this research have the potential to help clinicians and physical therapists create efficacious rehabilitation treatments and guidelines and ultimately improve the overall health and quality of life of obese children.

Public Health Relevance

Due in part to physical inactivity, nearly one third of US children are either overweight or obese. Childhood obesity has been linked to greater risk of obesity, cardiovascular disease and premature death in adulthood. In children, excess body mass can result in lasting musculoskeletal disability and a cycle of perpetual weight gain. Despite the urgent need to help overweight and obese children engage in physical activity for the purpose of weight management, little research has been conducted to identify the potential risks that physical activity may pose to the growing musculoskeletal system. This research will help obese children overcome disability by providing the groundwork for clinicians to design safer rehabilitation treatments and walking and running exercise guidelines aimed at weight management.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Predoctoral Individual National Research Service Award (F31)
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Special Emphasis Panel (ZRG1)
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Grave, Gilman D
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Colorado State University-Fort Collins
Other Health Professions
Sch of Home Econ/Human Ecology
Fort Collins
United States
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Lerner, Zachary F; Board, Wayne J; Browning, Raymond C (2016) Pediatric obesity and walking duration increase medial tibiofemoral compartment contact forces. J Orthop Res 34:97-105
Lerner, Zachary F; Browning, Raymond C (2016) Compressive and shear hip joint contact forces are affected by pediatric obesity during walking. J Biomech 49:1547-1553
Lerner, Zachary F; DeMers, Matthew S; Delp, Scott L et al. (2015) How tibiofemoral alignment and contact locations affect predictions of medial and lateral tibiofemoral contact forces. J Biomech 48:644-50