Article

Walking is a recommended form of physical activity for obese adults, yet the
effects of obesity and walking speed on the biomechanics of walking are not well
understood. The purpose of this study was to examine joint kinematics, muscle
force requirements and individual muscle contributions to the walking ground
reaction forces (GRFs) at two speeds (1.25 ms(-1) and 1.50 ms(-1)) in obese and
nonobese adults. Vasti (VAS), gluteus medius (GMED), gastrocnemius (GAST), and
soleus (SOL) forces and their contributions to the GRFs were estimated using
three-dimensional musculoskeletal models scaled to the anthropometrics of nine
obese (35.0 (3.78 kg m(-2)) ; body mass index mean (SD)) and 10 nonobese (22.1
(1.02 kg m(-2))) subjects. The obese individuals walked with a straighter knee in
early stance at the faster speed and greater pelvic obliquity during single limb
support at both speeds.
Absolute force requirements were generally greater in
obese vs. nonobese adults, the main exception being VAS,
which was similar
between groups. At both speeds, lean mass (LM) normalized force output for GMED
was greater in the obese group. Obese individuals appear to adopt a gait pattern
that reduces VAS force output, especially at speeds greater than their preferred
walking velocity. Greater relative GMED force requirements in obese individuals
may contribute to altered kinematics and increased risk of musculoskeletal
injury/pathology. Our results suggest that obese individuals may have relative
weakness of the VAS and hip abductor muscles, specifically GMED, which may act to
increase their risk of musculoskeletal injury/pathology during walking, and
therefore may benefit from targeted muscle strengthening.
CI - Copyright (c) 2013 Elsevier B.V. All rights reserved.

Langue : ANGLAIS