The Impact of Obesity and Weight Loss on Gait in Adults - The Mechanobiology of Obesity and Related Diseases - page 131

erect walking pattern with less hip and knee flexion and more ankle plantar flexion
compared to lean individuals [ 12 ]. It is possible that in severely obese people, the
greater amount of forefoot abduction indicates the need for balance [ 32 , 33 ]. One
possible explanation for the higher hip abduction angle is that obese individuals try
to control their body sway and maintain their postural stability. The higher hip
abduction angle may also be due to excessive fat mass in their thighs.

4 Gait Kinetics in the Obese

Studies evaluating joint loading in obese subjects during gait have mainly focused
on investigations into GFRs [ 7 ] and joint moments [ 7 , 12 , 16 , 23 , 24 , 48 , 49 ]. No
previous

investigations have evaluated the impulsive loadings during initial

contact.

4.1 Ground Reaction Forces

Browning et al. [ 7 ] examined the effects of obesity on GRFs at different walking
speeds ranging from 0.5 to 1.75 m/s. Absolute anteroposterior and mediolateral
GRFs were significantly greater for the obese versus normal-weight subjects, and
decreased significantly at slower walking speeds in both groups. Furthermore,
Messier et al. [ 32 ] found a strong positive association between BMI and peak
GRFs in older adults with knee OA. However, Browning et al. [ 7 ] showed that at
slower gait speeds, the difference in absolute GRFs between obese and non-obese
individuals was smaller, but the normalized GRFs, i.e., GRF scaled to body
weight, did not differ between obese and normal-weight subjects at any speed.

4.2 Ankle, Knee, and Hip Joint Moments

There are inconsistent reports of the ankle, knee, and hip joint moment parameters
of walking in obese but otherwise healthy subjects (Table 3 ). These differing
results might partly be due to the walking speed used (e.g. standardized versus
self-selected speed) and the method used in normalization of the absolute joint
moment. Most of the studies have focused on analysis in the sagittal plane.
Three studies have evaluated the effects of standardized walking speed on
sagittal joint moments in the obese (Table 3 )[ 7 , 12 , 16 ]. DeVita and Hortobágyi
[ 12 ] demonstrated that obese but otherwise healthy subjects had a lower absolute
sagittal-plane knee moment at their self-selected walking speed, but equal hip and
knee moments while walking at the same speed as lean individuals (Table 3 ).
However, the obese participants had a significantly higher absolute ankle plantar