Biomedical Engineering Reference
In-Depth Information
foot structure and function as a result of bearing excessive mass over time, would
be associated with gait changes in obese individuals, although this notion remains
unexplored.
Although biomechanical mechanisms are likely to contribute to foot pain,
Tanamas et al. [
105
] revealed skeletal muscle mass was not significantly associated
with foot pain in obese adults, once the data were adjusted for fat mass, implying
weight per se was not the reason for the positive association between BMI and foot
pain. The authors speculated that because all fat mass parameters but not muscle
mass variables were associated with foot pain, and because androgenic distribution
of fat differed from a gynoid distribution in relation to foot pain, systemic processes
associated with adipose tissue were likely to be contributing to foot pain [
105
].
Carrying excess load in the abdominal region could affect an individual's posture or
gait differently relative to carrying excess load around the hips and, in turn, load the
feet in a detrimental biomechanical way [
105
]. For example, Teh et al. [
110
]
examined the static pressure distribution under the feet in underweight (n = 20;
age = 21.0 ± 3.2 years; BMI = 17.6 ± 1.0 kg/m
2
), normal (n = 50; age = 21.3 ±
36.7 years; BMI = 21.6 ± 1.6 kg/m
2
), overweight (n = 20; age = 21.3 ±
35.7 years; BMI = 26.7 ± 1.3 kg/m
2
), obese (n = 20; age = 26.0 ± 8.6 years;
BMI = 34.3 ± 3.0 kg/m
2
) and severely obese (n = 20; age = 25.4 ± 9.7 years;
BMI = 38.9 ± 3.6 kg/m
2
) individuals during relaxed standing. Whereas forefoot
peak pressures were higher in obese participants, rear foot peak pressures were
higher for the normal weight participants relative to their obese counterparts. The
authors speculated the increased forefoot peak pressures displayed by the obese
participants was due to a forward shift of their total body centre of gravity because of
the excessive adipose tissue [
110
]. Gravante et al. [
93
], however, noted the centre
of pressure location under the plantar surface of the feet relative to the inferior
borders of the posterior heels during bipedal standing was unaffected by obesity,
when 38 obese young adults (23 women and 15 men) were compared to 34 healthy
age-matched controls (18 women and 16 men). More importantly, the metabolic
effects of adipose tissue cannot be dismissed. Adipose tissue is highly metabolically
active, producing numerous adipokines [
111
], with fat depositions on different body
sites being shown to produce different adipokines [
112
]. Nearly all adipokines are
dysregulated in obesity whereby there is a down regulation of potentially beneficial
adipokines and an overproduction of pro-inflammatory cytokines [
111
]. Interest-
ingly, previous research has shown pro-inflammatory cytokines, such as tumor
necrosis factor-a, have a significant role in chronic lower back pain [
113
]. Whether
pro-inflammatory cytokines associated with obesity have a role in chronic foot pain
has not been systematically investigated.
4.3.3 Effects of Obesity in Adults on Plantar Heel Pain
Obesity in adults has been implicated in numerous common foot disorders, including
chronic plantar heel pain. For example, obese individuals (BMI [ 30 kg/m
2
) have
been reported to be 3-5.6 times more likely to present with heel pain (plantar
Search WWH ::
Custom Search