The Impact of Obesity and Weight Loss on Gait in Adults - The Mechanobiology of Obesity and Related Diseases - page 133

flexion moment compared to the lean participants. When scaled to body weight,
the peak extensor moment at the knee was severely reduced in the obese compared
to the lean participants. This indicates that obese individuals reorganize their
neuromuscular function to produce a gait pattern with a lower total load on the
knee joint [ 12 ]. On the contrary, Browning and Kram [ 7 ] reported a higher
absolute peak hip extension moment at nearly all standardized walking speeds
ranging from 0.5 to 1.75 m/s, and also a higher knee extension moment at a
walking speed of 1.75 m/s (Table 3 ). There were no significant differences
between obese and lean participants in normalized peak knee and hip extension
moments at each walking speed, but the normalized ankle peak plantar flexion
moment was significantly lower at every walking speed. Freedman Silvernail et al.
[ 16 ] also showed that the normalized peak knee flexion moment did not differ
significantly between groups at a standardized walking speed (Table 3 ).
A slower walking speed has led to lower relative joint flexion and extension
moments in the ankle, knee and hip in normal gait [ 27 ]. By walking at a slower
gait speed and taking shorter steps, obese individuals may tend to maintain a
similar joint loading to that of normal-weight persons [ 7 , 12 , 24 , 32 , 47 , 51 ]. Most
studies have shown that at the self-selected walking speed, the normalized ankle,
knee and hip sagittal moments do not differ significantly between obese and
normal weight subjects [ 12 , 23 , 24 , 59 ]. However, in one study, the plantar flexion
moment was significantly lower in the obese (Table 3 )[ 24 ].
The knee adduction moment has been associated with the development of knee
OA, especially in the obese [ 15 , 47 ]. The absolute peak knee adduction moment
has been shown to be significantly higher in obese subjects compared to normal-
weight subjects [ 7 , 49 ]. However, in one study there was no significant difference
in the absolute knee adduction moment [ 48 ]. In several studies, normalized knee
adduction moments have not differed between the two groups (Table 3 )[ 16 , 23 ,
24 , 49 ]. In the hip joint, the scaled adduction moment also did not differ signifi-
cantly between obese and non-obese subjects (Table 3 )[ 23 , 24 ]. Because the
normalized knee and hip joint adduction moments are similar between the two
groups, there is clearly no significant difference in gait pattern. In the ankle joint,
Lai et al. [ 24 ] showed that the normalized peak ankle inversion moment was
significantly higher in the obese compared to the non-obese, but Ko et al. [ 23 ]
found no such difference (Table 3 ).
4.3 Impulsive Loading Measurements
Joint loading has traditionally been estimated in joint moment analysis based on
inverse dynamics (e.g. joint moments). However, these methods do not permit the
assessment of impulsive loadings during the initial contact phase, whereas skin-
mounted accelerometers (SMAs) seem to be well suited for investigating impul-
sive joint loading in knee joints [ 28 - 30 ]. Although SMAs cannot measure the real
forces on knee joint surfaces, they are practical for use in clinical gait analysis,