Biomedical Engineering Reference
In-Depth Information
adiposity can influence the amount of soft tissue beneath the feet in both children
[
52
,
68
] and adults [
103
]. However, Wearing et al. [
94
] determined the effect of
variations in BMI on the structure of the arch of the foot in a convenience sample
of 10 male and 20 female healthy volunteers (age = 47.9 ± 11.6 years;
BMI = 28.8 ± 2.9 kg/m
2
). The arch of the foot was characterised by both
radiographic and footprint-based measures using a pressure platform. Whereas
BMI was a significant (p = 0.04) predictor of footprint-based measures of arch
height, arch structure quantified by a radiographic measure of the medial longi-
tudinal arch was not significantly associated with BMI (p = 0.89). The authors
concluded that although adult obesity selectively distorts footprint-based measures
of arch structure by increasing the midfoot contact area, it does not influence
osseous alignment of the medial longitudinal arch in adults [
94
].
4.3.2 Effects of Obesity in Adults on Foot Pain
Clinical data have confirmed obese adults report a greater prevalence of musculo-
skeletal pain than their non-obese counterparts, particularly lower limb pain [
104
],
although the foot is often overlooked when seeking participant responses about their
experience of musculoskeletal pain. Tanamas et al. [
105
] examined the relationship
between obesity, body composition, and foot pain as assessed by the Manchester
Foot Pain and Disability Index (MFPDI) in 23 men (age = 47.6 ± 8.1 years) and
114 women (age = 47.5 ± 9.2 years) who ranged from normal weight to obese
(BMI = 32.1 ± 8.4 kg/m
2
). Foot pain was defined as current foot pain and pain in
the last month, and a MFPDI score of C1. Seventy-five participants (55.1 %)
reported foot pain, with a positive association established between BMI and foot
pain (OR 1.11, 95 % CI 1.06-1.17). Those participants who reported foot pain had a
significantly higher mean BMI, total fat mass, fat mass index and fat-free mass index
than those without foot pain, although the two participant groups did not signifi-
cantly differ in terms of age, sex or skeletal muscle mass. More importantly, a higher
percentage of android fat mass (adipose tissue accumulated in the abdominal region)
increased the odds for foot pain, whereas a higher percentage of gynoid fat (adipose
tissue accumulated around the hips) decreased the odds of foot pain [
105
].
It has traditionally been thought that obesity affects foot pain via biome-
chanical mechanisms where the excess mass associated with being overweight or
obese causes increased loading [
85
,
106
] or altered foot mechanics during
walking, indicated via abnormal foot/ground contact patterns [
8
,
96
]. This
increased loading or abnormal foot mechanics can, in turn, damage soft tissue
structures within the foot and lead to the development of musculoskeletal pain
[
107
]. In support of this notion, it has been consistently reported that obese adults
walk slower than their non-obese counterparts, and with a reduced step length
and cadence, longer stance duration and increased time spent in double support
[
108
,
109
]. However, the reasons for obese individuals adopting this altered gait
pattern are seldom discussed. Given the role of feet as the base of support during
weight-bearing activities, it would seem logical that foot pain, or alterations to
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