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In assessing the influence of shoes on human movement, one has to look at
several factors besides the expenditure of energy over a prolonged period. The
mass of a shoe also can significantly affect the agility of even short distance
athletes like jumpers and weightlifters. If one measures or computes the torque
about the knee and hip joints or the force required to accelerate the foot
during a jerk or snatch, the very small difference that an extra 100gm seems to
make may seem inconsequential, but analysis based solely on biomechanical grounds ignores the very real effect of perceived change which added loading to
the distal extremities can cause.
If the shoe 'feels' heavier (according to the Weber-Fechner Law), then the
movement pattern of the athlete can be altered and lead to reduced agility and
speed. This effect is well known to sprinters and high jumpers, as well as
lifters whose feet 'feel heavier and slower' with perceptibly heavier shoes.
Though I have not encountered any studies on foot speed with different shoes in
weightlifting, from my personal experience of several decades of competing in
and coaching weightlifting, I have encountered sufficient numbers of lifters who
have felt that they were more agile with lighter shoes. That is one reason why
some lifters choose not to wear the heavier, wooden-soled, though, very stable
Adidas lifting shoe.
So, in assessing any shoe, it is most relevant to focus not only on objective
mechanical factors such as the resilience and stability of the shoe, but also
the athlete's subjective assessment of the shoe under actual sporting
conditions.
If the ankles do not tilt in a direction of excessive supination or pronation
under loading, then no special modifications to lifting shoes are necessary.
I did not wish to complicate matters by contrasting loaded and unloaded
neutrality of the subtalar joint during the different lifts, because that is
another topic in itself. Scientific debate and practical experience on that
score eventually led to most lifters choosing not to use any high-cut boots that
'support the ankles', even though lower-cut lifting shoes apparently increased
the likelihood of deviations from a position of ankle 'neutrality'.
But, while we are on this point, it is essential to note that lifters often
deliberately alter foot position and relative degrees of pronation/supination
and eversion/inversion (including hip and knee rotation) to suit individual
needs and preferences during the different lifts. Thus, you will have some
squatters who intentionally try to roll the foot outwards and force the knees laterally to ensure a more powerful squat or pull. Others may rotate the knees
noticeably outwards during the clean, snatch or deadlift to allow the bar to
move closer to the body. During the early recovery phase of the snatch and clean, there can be considerable voluntary or involuntary movement of the foot
and toes to ensure that the bar remains stable in its position either on the
chest or at arms length overhead.
These complexities and idiosyncrasies of foot action during Powerlifting and
Weightlifting make it very difficult to objectively compute the design of a shoe
or orthotic device for these athletes. The bar is never pulled, caught or thrust
in exactly the same way with each attempt and it is only years of experience
that enable one to cope efficiently and safely with all aspects of body control,
including foot movement with all of its subtleties in preventing failure of a
lift.
A huge amount of research is done in gait laboratories around the world on the
biomechanics of the lower extremity, with most of it focused on walking and
running. It would be most interesting to see more projects devoted to
understanding lower extremity and shoe mechanics during Weightlifting and
Powerlifting.
Dr Mel C Siff
Denver, USA
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