TY - JOUR
T1 - Compressive and shear hip joint contact forces are affected by pediatric obesity during walking
AU - Lerner, Zachary F.
AU - Browning, Raymond C.
N1 - Funding Information:
This research was supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health under Award Number F31HD080261 and by an ACSM Foundation Research Grant from the American College of Sports Medicine . We thank the Medical Center of the Rockies Healthy Hearts program for their assistance in participant recruitment. We also thank all of the researchers associated with Orthoload for making their valuable datasets publically available.
Publisher Copyright:
© 2016.
PY - 2016/6/14
Y1 - 2016/6/14
N2 - Obese children exhibit altered gait mechanics compared to healthy-weight children and have an increased prevalence of hip pain and pathology. This study sought to determine the relationships between body mass and compressive and shear hip joint contact forces during walking. Kinematic and kinetic data were collected during treadmill walking at 1 m s-1 in 10 obese and 10 healthy-weight 8-12 year-olds. We estimated body composition, segment masses, lower-extremity alignment, and femoral neck angle via radiographic images, created personalized musculoskeletal models in OpenSim, and computed muscle forces and hip joint contact forces. Hip extension at mid-stance was 9° less, on average, in the obese children (p<0.001). Hip abduction, knee flexion, and body-weight normalized peak hip moments were similar between groups. Normalized to body-weight, peak contact forces were similar at the first peak and slightly lower at the second peak between the obese and healthy-weight participants. Total body mass explained a greater proportion of contact force variance compared to lean body mass in the compressive (r2=0.89) and vertical shear (perpendicular to the physis acting superior-to-inferior) (r2=0.84) directions; lean body mass explained a greater proportion in the posterior shear direction (r2=0.54). Stance-average contact forces in the compressive and vertical shear directions increased by 41 N and 48 N, respectively, for every kilogram of body mass. Age explained less than 27% of the hip loading variance. No effect of sex was found. The proportionality between hip loads and body-weight may be implicated in an obese child's increased risk of hip pain and pathology.
AB - Obese children exhibit altered gait mechanics compared to healthy-weight children and have an increased prevalence of hip pain and pathology. This study sought to determine the relationships between body mass and compressive and shear hip joint contact forces during walking. Kinematic and kinetic data were collected during treadmill walking at 1 m s-1 in 10 obese and 10 healthy-weight 8-12 year-olds. We estimated body composition, segment masses, lower-extremity alignment, and femoral neck angle via radiographic images, created personalized musculoskeletal models in OpenSim, and computed muscle forces and hip joint contact forces. Hip extension at mid-stance was 9° less, on average, in the obese children (p<0.001). Hip abduction, knee flexion, and body-weight normalized peak hip moments were similar between groups. Normalized to body-weight, peak contact forces were similar at the first peak and slightly lower at the second peak between the obese and healthy-weight participants. Total body mass explained a greater proportion of contact force variance compared to lean body mass in the compressive (r2=0.89) and vertical shear (perpendicular to the physis acting superior-to-inferior) (r2=0.84) directions; lean body mass explained a greater proportion in the posterior shear direction (r2=0.54). Stance-average contact forces in the compressive and vertical shear directions increased by 41 N and 48 N, respectively, for every kilogram of body mass. Age explained less than 27% of the hip loading variance. No effect of sex was found. The proportionality between hip loads and body-weight may be implicated in an obese child's increased risk of hip pain and pathology.
KW - Gait biomechanics
KW - Joint loading
KW - Musculoskeletal modeling
KW - Obesity
KW - OpenSim
KW - Orthopedics
KW - Personalized
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U2 - 10.1016/j.jbiomech.2016.03.033
DO - 10.1016/j.jbiomech.2016.03.033
M3 - Article
C2 - 27040390
AN - SCOPUS:84979463109
SN - 0021-9290
VL - 49
SP - 1547
EP - 1553
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 9
ER -