Differences and mechanisms
differences were found wearing neutral shoes
compared to stability or barefoot conditions
(p > 0.05). At the hip, the stability shoes
(MD = 2.81, 95% CI 1.79, 3.82 °, p < 0.001) and
neutral shoes (MD = 2.40, 95% CI 1.52, 3.28°,
p < 0.001) increased the flexion angle at peak
KFM compared to barefoot, with no between
shoe differences evident (p = 0.43).
Differences between footwear and barefoot
were also evident for knee excursion angle
across the stance phase with higher values
wearing stability (MD = 3.82, 95% CI 2.99, 4.65°,
p < 0.001) and neutral shoes (MD = 3.92, 95%
CI 3.19, 4.64°, p < 0.001) compared to barefoot.
Surprisingly, knee flexion angle at initial contact
was lower in stability shoes compared to neutral
shoes (MD = 1.48, 95% CI 0.07, 2.90°, p = 0.04)
and barefoot (MD = 2.95, 95% CI 1.96, 3.95°,
p < 0.001), with the neutral shoes revealing lower
angles at initial contact compared to barefoot
(MD = 1.47, 95% CI 0.25, 2.70°, p = 0.02).
Predictors underlying change in peak KFM
between footwear and barefoot conditions
There was evidence of an interaction between
footwear condition and the change in knee-
GRF lever arm (p-value for interaction < 0.001,
Additional file 2: Table S1). Subsequently, this
interaction term was considered for each
condition (barefoot and footwear) in the final
regression model analyzing factors associated
with change in peak KFM between footwear
and barefoot conditions. This model included
a total of nine potential predictors (Table 4), of
which, only the change in knee-GRF lever arm
in barefoot (MD = 0.02, 95% CI 0.02, 0.03 mm,
p < 0.001) and footwear conditions (MD = 0.02,
95% CI 0.01, 0.03 mm, p < 0.001) had a
statistically significant association with a change
in peak KFM. The change in sagittal-plane
resultant GRF magnitude, footwear condition
and change in hip, knee and ankle kinematics
did not have statistically significant associations
with a change in peak KFM in this regression
model (p > 0.05, Table 4).
Discussion
Running is a popular form of exercise amongst
adolescent girls and young women. This study
found a higher peak KFM during running
whilst wearing both stability and neutral shoes
compared to barefoot, with no strong evidence
of between-shoe differences in this sample.
Furthermore, a novel finding of this study was a
change in the knee-GRF lever arm is associated
with a change in peak KFM wearing shoes
compared to barefoot.
Higher running-related peak KFM in adolescent
girls and young women wearing stability and
neutral shoes compared to barefoot partly
supports the primary hypotheses but does
not support the hypothesis of a between-shoe
difference in peak KFM. Previous studies have
reported increased running-related peak KFM
wearing stability shoes and neutral shoes
compared to barefoot amongst mixed adult
cohorts aged 26–29 years [8, 20] , but between
shoe comparisons have not been previously
performed. The present study now extends these
results to adolescent girls and young women
and is the first to include a direct comparison of
stability and neutral shoes. The lack of between-
shoe differences in peak KFM suggests that the
relevant shoe design features such as footwear
pitch did not influence peak KFM.
The regression analysis revealed an association
between a change in peak KFM and a change in
Current Pedorthics | March/April 2019
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