Dr Mel Siff Blog

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Member 1:

<<Even if you do not consider technique or differences in lifting styles
(flat-footed vs. plantarflexed), you have to agree that the extra 2-3 inches
of bar height you will gain just by extending onto the balls of the feet
could be paramount to a successful max lift.>>

Member 2:

<This is only true if the peak velocity occurs following the plantarflexion
(and before the squat under). If peak velocity occurs prior to
plantarflexion, and the lifter continues to rise onto the toes, they lose
valuable time that could be used to get under the bar because the bar has
begun to decelerate.>

Dr Mel Siff:  True, but no experienced lifter who uses some degree of plantarflexion
times the plantarflexion action in that inefficient manner.

Member 1:

<<Also, from a biomechanical perspective, it does not make sense that one can
get a more powerful pull by NOT extending the ankles. Considering that the
force applied to the bar during the lift is proportionately related to the
sum of all joint torques, if you have more joints generating extension
torques, you will obviously have higher totals (assuming technique is not a
factor).>>

Member 2:

<But if plantarflexion occurs subsequent to full hip and knee extension, the
hip and knee extensor musculature can no longer apply force to raise the
barbell (or the barbell/lifter system). Therefore, can plantarflexion apply
force greater than that already applied by the hip and knee extensors to
continue to (postively) accelerate the barbell? It is not simply a matter of
applying greater force, or having greater power, the timing of these
variables is equally important (Enoka, MSSE, 1979).>

Dr Mel Siff:

*** Of course, you will have noticed in Enoka’s 1979 paper that two velocity
peaks were identified: one before the bar reached knee level and the next, of
slightly greater magnitude, after the “double knee-bend” action. Moreover,
the lifters in his study were using the “old” plantarflexed style, so we
cannot judge which kinesiological differences occur when a flatfooted pull is
used. Anyway, it is extremely difficult to produce any degree of forceful
plantarflexion after full hip and knee extension, because the body
reflexively integrates plantarflexion into a linked chain of joint extending
actions involving an optimal sequence of knee, hip and ankle extending
actions. A simple experiment – lock your knee and hips, and do not extend
your trunk and see how high you can jump off the ground using ankle
plantarflexion alone.

Member 2:

<This is not to suggest that lifters should not ALLOW plantarflexion to
occur. However, it should be considered that plantarflexion may be a
function or artifact of the vertical momentum of the lifter/barbell system
created by the hip and knee extensors (from Newton, an object in motion …),
rather than consequence of a conscious effort to rise onto the toes.>

Dr Mel Siff:

*** In other words, this comment supports alternative #3 in my original
letter on this topic. Yet, there are some coaches who vehemently militate
against allowing the heels to leave the platform. Just to remind those who
may not have read my original letter, here is its closing statement:

<What I saw was that most lifters still pull with a significant degree of
plantarflexion, so it would be interesting to know why this is so, assuming
that this method should be regarded as archaic and inefficient.

This suggests one of several things:

1. The majority of modern lifters are lifting in an inefficient manner and
would improve their totals if they changed to the more flatfooted pulling
style.

2. Those lifters have found that the plantarflexed pulling style produces
better results for them. In other words, different pulling styles suit
different individuals, but that the plantarflexed style suits most lifters.

3. Most lifters don’t really concern themselves with what happens to their
heels during the pull and that they simply focus on pulling as powerfully as
possible, no matter whether this involves plantarflexion or not.

Which of the above possibilities is correct? Or are there other alternatives?
>

Dr Mel Siff
Denver, USA
http://groups.yahoo.com/group/Supertraining/

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Tags: clean, Double Knee Bend, Dr Mel Siff, Hip And Knee, Knee Extension, Knee Extensors, Knee Level, Magnitude, Mel Siff, Musculature, olympic lifting, Peak Velocity, Plantarflexion, pull, Squat, Super Training, Supertraining, Torques, Weightlifting