Biomedical Engineering Reference
In-Depth Information
Vela et al. [
106
] examined the plantar pressures generated during walking by 10
men (age = 29.7 ± 5.6 years; BMI = 24.9 ± 1.7 kg/m
2
) and 9 women
(age = 32.4 ± 5.5 years; BMI = 23.2 ± 3.7 kg/m
2
) who were free of sensory
neuropathy or other systemic disease. Peak plantar foot pressures were measured
while the participants walked firstly with no additional mass and then with an
additional 9.1 kg and an additional 18.2 kg of mass evenly distributed in pockets
on the front and back of a vest. For each incremental increase in mass there was a
significant increase in the mean peak plantar foot pressures under the metatarsal
heads, heel and midfoot. The addition of 9.1 kg and 18.2 kg of mass increased
average peak foot pressures by 5 and 19 % in men and 9 and 25 % in women,
respectively. The authors concluded that increased mass could significantly
increase pressures on the plantar surface of the feet of adults, even when other
confounding factors, such as the presence of deformities and limited joint mobility,
were controlled [
106
].
Hills et al. [
85
] conducted the first investigation of differences in the plantar
pressures between obese and non-obese adults during standing and walking tasks.
Thirty-five men (age = 42.4 ± 10.8 years) and 35 women (age = 40.0 ±
12.6 years) were divided into an obese (BMI = 38.75 ± 5.97 kg/m
2
) and a non-
obese (BMI 24.28 ± 3.00 kg/m
2
) sub-group. The obese participants displayed
significantly higher plantar pressures under the heel, midfoot and metatarsal regions
of the foot during both standing and walking relative to their non-obese counter-
parts. The highest pressure increases in the obese participants were found under the
longitudinal arch of the foot and the metatarsal heads. Compared to the non-obese
groups, increases in pressure under the midfoot and the middle of the forefoot were
higher for the obese women compared to the obese men during standing. For
example, under the midfoot, the obese women displayed 7.7 times and the obese
men 3.1 times higher pressures than their respective control groups. The authors
speculated that this between-sex difference in plantar pressures might have been the
result of reduced strength of the foot ligaments in obese women relative to their
male counterparts [
85
]. The authors further speculated that physiological mani-
festations of the increased loading associated with bearing excess body mass might
be reflected in self-reported pain, soreness or discomfort in the lower extremity,
including plantar heel pain described previously in this chapter. In contrast to these
findings in which increased peak plantar pressure values were evident across all
foot regions, Birtane and Tuna [
118
] reported that obese participants (20 women
and 5 men; age = 53.0 ± 9.5 years; BMI = 32.2 ± 2.0 kg/m
2
) displayed signif-
icantly higher peak pressure values only in the forefoot region during static
standing, and in the middle foot when walking, compared to non-obese controls (18
women and 7 men; age = 48.0 ± 12.2 years; BMI = 24.2 ± 3.4 kg/m
2
). The
authors suggested that their results differed to those reported by Hills et al. [
85
]
because their study sample included less-obese individuals. They speculated that
plantar pressure increases are likely to begin from the middle foot in low-grade
obese individuals and then progress to affect the whole foot as obesity levels
increased. It should be noted that comparing the results of all plantar pressure
studies described above is somewhat confounded by the different systems used to
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