HIT-infos(lang,englisch)

[klaus]

hier ein artikel von mel siff zu dem thema:


FAULTY BRZYCKI BIOMECHANICS

Mel C Siff PhD


Matt Brzycki appears to be one of the more vociferous proponents of HIT
training and, as such serves as one of its more important spokesmen.
However, when he strays off his more practical side of the subject into
matters of science, he makes various errors which reflect poorly on the image
of HIT. This is evident if one examines just a few extracts from one of his
articles on Cyberpump:

< http://www.cyberpump.com/trainhard/pubs.html>

Lest what I write leads to the usual personal attacks which have nothing to
do with science or matters of content criticism, let me state at the outset
that I have no specific emotional attachment to any type of training, since I
have found that many types of training can play a role at some stage or other
in the training of the individual, and that what suits you at one time does
not necessarily suit you at another time (as your readers may confirm by
consulting my strength training textbook, “Supertrainingâ€*). Sometimes I
enjoy some training to failure, sometimes I enjoy some classical
bodybuilding methods, other times I revel in Olympic weightlifting or
powerlifting, sometimes I am dedicated to martial arts, at times I teach
aerobics, I swim most days, periodically I might indulge in some plyometrics,
at other times I think Dinosaur training is great fun - in short, I strongly
believe in an ad hoc, more “holisticâ€* approach to training, guided by what
my body tells me at a specific time.

Therefore, my comments are not based on what you might refer to as “NSCA
hypeâ€* or similar schools of training approach. As a sports scientist,
biomechanist, coach and competitive athlete, it concerns me that Brzycki’s
material shows a deficient working knowledge of some basic mechanics and it
is important that these technical errors be addressed if HIT is not to be
seriously misrepresented.

<More Fitness Facts and Fables

by Matt Brzycki

Furthermore, whenever you lift a weight explosively momentum is introduced to
overcome inertia and provide impetus to the weight or resistance. After the
initial explosive movement, little or no resistance is encountered by the
muscles throughout the remaining ranges of motion. In simple terms, the
weight is practically moving under its own power.

To illustrate the effects of momentum on muscular tension, imagine that you
pushed a 100 pound cart a distance of 50 yards at a deliberate, steady pace.
In this instance, you maintained a constant tension on your muscles for the
entire 50 yards. Now, suppose that you were to push the same cart another 50
yards. This time, however, you accelerated your pace to the point where you
were running as fast as possible. If you were to stop pushing the cart after
35 yards, the cart would continue to move by itself because you gave it
momentum. So, your muscles had resistance for the first 35 yards . . . but
not for the final 15 yards. The same effect occurs in the weight room. When
weights are lifted explosively, there is tension on the muscles for the
initial part of the movement . . . but not for the last part. In effect, the
requirement for muscular force is lessened and the potential strength gains
are reduced accordingly.

Now, here's where we get to the good stuff. Using momentum to lift a weight
increases the internal forces encountered by a given joint; the faster a
weight is lifted, the greater these forces are amplified. These high forces
are created at the point of explosion. When the forces exceed the structural
limits of a joint, an injury occurs in the muscles, bones or connective
tissue .....

Assuming that an object's mass (or weight) does not change, the amount of
potential force is then directly related to the object's acceleration. In
other words, as the speed of movement increases so does its potential force.
That's not merely my opinion or observation -- it's a fundamental law of
physics. Something new? Nope. In fact, it was first proposed about 300 years
ago by a dude named Isaac Newton and is referred to as his Second Law of
Motion. >

*** This perpetuates the view that most HIT material tends to be supported on
very emotional and personal grounds. It is not my intention at all to
address HIT philosophy or beliefs, which have no bearing whatsoever on the
problem. Instead, I wish to confine myself to the alleged science which is
used to support this material. Here are a few comments in this regard:

1. How it is possible to lift a weight WITHOUT the use of momentum?
Momentum is defined as the product of mass x velocity (p = M.V) for a mass M
moving at a constant velocity V, so that movement at ANY velocity creates
momentum. Some change of momentum is necessary to change the existing state
of a body at rest or constant velocity - at least that is what Newton's
First Law implies.

2. One does not use momentum to lift a weight. One uses FORCE to overcome
the weight exerted by a load being kept on the surface of the Earth by the
pull of gravity. Momentum is the result of force being exerted on the body.

Since Brzycki quoted Newton's 2nd Law, then he surely should remember the 1st
Law by the same 'dude', which ran something like this:

"A body will remain in its original state of rest or movement at constant
velocity unless acted upon by an outside force."

Note that Newton wrote about force and not momentum - he only wrote about
momentum in his 2nd Law, which was not really stated as F = Mass x
Acceleration. What Newton actually wrote was close to this:

"The force (implied by the 1st Law) acting on a body is proportional to the
rate of change of momentum".

This, of course, emphasizes that it is not momentum, but rate of momentum
change which gives rise to a force, but if one has received a limited
exposure to biomechanics and physics in formal education, some of the
precise subtleties of these subjects understandably may be missed.

3. What is meant by "potential force"? Potential refers to something that
has not really happened, not something that is in progress, as in the
situation above. This redundant terminology adds no understanding to the
problem, but possibly has been employed in some attempt to impress with
jargon, like many other ‘fitness gurus’.

4. In stating that "whenever you lift a weight explosively momentum is
introduced to overcome inertia and provide impetus to the weight or
resistance", Brzycki failed to point out the underlying equation (or
popularised deductions based upon it) which applies to the motion of the load
and the lifter. This information would have shown his readers that, if one
is lifting a load against gravity and then ceases to apply force, then there
will be no upward acceleration and the load will be decelerated and slowed
down by gravity. Even if the load is fairly light (say, about equal to
bodymass), the moment imparted by the initial pull is insufficient to lift
the bar very far without continued application of force, as has been shown in
many biomechanical studies.

If the load is closer to a typical weightlifting training load of over 80% of
1RM, the momentum does not endlessly keep moving the load upwards, since it
is rapidly decelerated. Here are some interesting biomechanics results that
totally negate Brzycki's argument about the risks of allegedly large terminal
momentum:

Parameters of the Pull during the Clean

Force at start of pull = 140-160% of weight on bar
Force during the double-knee bend phase = 160-180% of weight
Force near catch of load = 100-70% of weight (near end of movement)

Similar results are obtained from analysis of the jerk and the snatch. In
other words, the force near the end of the movement is LESS than during
earlier stages of the pull, so Brzycki errs in condemning explosive movements
on the basis of what momentum does near the end of the action.

Of course, it appears to the untutored observer that the bar actually is
moving very rapidly in the Olympic lifts, but research shows that it is the
RELATIVE velocity of the bar which is large, not necessarily the ABSOLUTE
velocity of the bar which is large. The relative velocity is large because
of that Newton dude's 3rd Law which states that "for every action there is
an equal and opposite reaction". How is this law involved in lifting? Well,
during the drop phase under the bar, the lifter actively thrusts against the
bar to propel himself into the final catch position.

Brzycki continues to say: "After the initial explosive movement, little or no
resistance is encountered by the muscles throughout the remaining ranges of
motion. In simple terms, the weight is practically moving under its own
power." By focusing his attention on the muscles, he has ignored the
concurrent dynamics of the external load and the lifter's body. Had he done
so, he would have realised that, although there is no significant resistance,
there was still plenty of inertia involved and that gravity would have a
major say in determining the ultimate fate of the upward moving bar.
Vertically projected loads on planet Earth generally tend to be slowed down
by the effects of gravity, whether they encounter other resistance or not, as
everyone knows.

5. It is incorrect to state that the Olympic lifter does not apply continued
force throughout the Olympic lifts. This reveals a serious lack of
understanding of the biomechanics of the Olympic lifts. As discussed above,
the ever-present force of gravity is acting on the bar tending to slow it
down and the lifter applies varying degrees of force at every different stage
of the movement in response to proprioceptive feedback from various parts of
the body in an attempt to ensure that there is adequate force present to move
the bar as high as possible.

EMGs have frequently been taken during all of the lifts and show that
considerable activity of many muscle groups occurs throughout the lifting and
jerking movements (see Vorobyev "Textbook on Weightlifting 1978, for
example). Lifters do not depend on a single ballistic pull or thrust to move
a load overhead; they rely on a combination of momentum and continued
application of muscular force (or in other words, on a combination of kinetic
and potential elastic energy).

Now for the really bad news for Brzycki’s analysis - what he says about the
risks of momentum and imposition of large terminal forces applies more
accurately to situations when the unloaded body or very light loads are
involved in sport and training. Thus the accelerations and very often, the
joint and muscle forces experienced in activities such as running, jumping,
hitting and throwing can far exceed those of Olympic lifting. For instance,
sprinting and jumping can easily impose impact forces on the body which
exceed 8 times bodyweight. Biomechanics studies of the Olympic lifts
generally show that even the most powerful lifters do not exert a maximum
pulling or jerking force that exceeds about 1.8 times the weight on the bar
(about 4 times the bodymass of the lifter).

In simple terms this means that anyone who opposes “ballisticâ€* or
“explosiveâ€* training should condemn sports such as track and field,
basketball, football, tennis, hockey, baseball and almost all other sports
which involve running and jumping - if, of course, we apply Brzycki’s
principle of the dangers posed by momentum.

6. Brzycki's comments suggest that the use of ballistic action is inherently
dangerous and inefficient. Had he read some of the outstanding early texts
by scientists such as McNeil Alexander, he might have noticed that the use of
ballistic actions actually enhances the efficiency and safety of animal
motion in terms of thermodynamics and mechanics. What can be dangerous is
the inappropriate application of forces and the production of inappropriate
motor patterns. What also needs to be pointed out that no research has ever
shown that ballistic or rapid movements are any more likely to cause injury
than slower or static actions. In fact, some of the most debilitating injury
or dysfunction involves prolonged sitting without movement. Very serious
muscle ruptures have also taken place during intense isometric and very slow
loaded movements.

7. Bryzcki states that "These high forces are created at the point of
explosion". This is frequently correct, but the production of these forces
is not in the form of a "step function" in which the force starts from zero
and immediately reaches a peak value. Force is always developed according to
a specific ramping or building up pattern. The ability of the body to
produce force rapidly is controlled by proprioceptive and cognitive feedback
processes which rarely allow the lifter to voluntarily produce forces that
will exceed the tensile limit strength of the soft tissues.

As a safeguard, these tissues have built into them what is known in
engineering as a "Safety Factor" which provides a large safety margin that is
rarely reached, except under unexpectedly demanding situations (such as
during accidents or sudden tackles), or if the muscles are activating in
inefficient patterns, or if the integrity of the tissues has already been
compromised by disease, inflammation, injury or other pathology.

8. Brzycki casually stated that "the faster a weight is lifted, the greater
these forces are amplified." What is meant by force amplification? Is he
talking about amplification scientifically as the increase in the magnitude
of a motor output by means of some active intervention of certain magnifying
processes within the 'black box' of the body? This implies the action of
further ongoing forces, but this cannot be his intention, since he was
referring to momentum-driven action in which no ongoing force application is
taking place.

9. Brzycki states that "When weights are lifted explosively, there is tension
on the muscles for the initial part of the movement . . . but not for the last
part". This is not necessarily correct, because numerous EMGs of various
movements show that the so-called "antagonistic" muscles contract, sometimes
very powerfully, near the end of a movement to ensure that joints are not
extended unsafely beyond their maximum range of movement (e.g. see Basmajian
"Muscles Alive" and Vorobyev's "Textbook on Weightlifting").

It would have been more accurate if Brzycki had restrained his prejudice against
rapid training and Olympic lifts and stated more objectively that any form of
static, dynamic or ballistic activity carried out with poor motor skill carries
with it an increased risk of injury.

He might have stated, too, that virtually all types of training may play a
useful role at some stage of training an individual athlete, and that safety and
efficiency depend more on knowing how and when to use each of those different
training methods than the exercises on their own. I certainly would not condemn
HIT out of hand, because it may play some role in training for any given
individual during a given training phase. Similarly, one might even rule out
plyometric training for some individual athlete since it may be unproductive or
harmful in that case. A good coach, like a good chef, knows how to mix the
ingredients for the best results! He does not throw out the vinegar because it
is sour; he uses it where it is most appropriate to enhance the flavour of the
gourmet meal.

Brzycki’s lack of peer-reviewed clinical evidence and his flawed biomechanical
analysis of lifting do not offer logical scientific proof of his case. It is
regrettable that he taints his undoubted practical experience with far too much
prejudice. While I certainly agree, for example, that plyometric training is
often massively misunderstood, misapplied and overused by certain gurus in the
USA, one should rather return some more sanity to the situation by means of
valid theory and research, not simply emotive prejudice and pseudo-science.
Sadly, Brzycki often does more harm to the cause than do many of his opponents,
simply because of his lack of objectivity.


cheers,klaus

[hps]

Hallo Klaus,

interessanter Artikel. Muss allerdings zugeben, dass ich den Originalartikel von Brzycki nicht gelesen habe. Kann mir aber denken, dass er dort eher darauf abhebt, Übungen relativ langsam ohne merkliche Beschleunigung auszuführen.

Gut, dass Siff mal erklärt, dass es ohne Beschleunigung nicht geht. Und wenn man nicht dauernd Kraft ausüben würde, dann würde die Hantel aufgrund der Gravitationskraft auch ganz schnell zum Stillstand kommen.

Hab' mir das Buch von Siff (Supertraining) aus den USA besorgt. Da ich aber nur ein Hobby-Kraftsportler bin und ich das Zeug auch nicht studiert habe, ist das Buch eine echte Herausforderung für mich.

Noch eine Frage an Dich: Habe gerade ein 5-Wochen-Zyklus mit Speed und Max-Training hinter mir und BP von 90 auf 95 Kg gesteigert. Morgen kommt dann KB dran und hoffe von 100 auf 105 steigern zu können. Ich denke jetzt darüber nach, bei BP von einem normalen auf einen engen Griff zu wechseln. Mein Trizeps ist nicht soooo stark. Andererseits hat es mich bisher noch nicht zerissen und ich könnte vielleicht noch einen 5-Wochen-Zyklus ohne Veränderung absolvieren.

Ich war vor ein paar Jahren schon mal bei 105 Kg Bankdrücken (3-4 reps gingen damals mit dem Gewicht). Ich würde halt gerne dieses Jahr die 100 Kg wieder knacken können. Nur wenn ich jetzt den Griff umstelle, dann muss ich mit deutlich weniger Gewicht trainieren, und ich schaff die 100 dieses Jahr nicht mehr.

Mann, mann, wer solche Probleme hat, dem kann es eigentlich nur zu gut gehn... ;-)

Gruß
Hans-Peter

[kurt]

aber dass diese methodik effizient ist, ist keine frage. ich habe über 20 jahre nach "schema f" trainiert. klaus hat meinem krafttraining in der tat leben eingehaucht (auch, wenn ich nur 1x/wo trainiere)

gruß, kurt (der vor jahren schon mal bei 130kg auf der bank war und nach seiner 3-monatigen sommerpause hoffentlich in einigen wochen wieder dort ist)

[klaus]

hi!
ich würd mal auf engen griff wechseln und einfach ca 3w vor jahresende wieder auf normal gehn....die 100 sollten dann schon drin sein!
cheers,klaus

[hps]

Hallo Klaus,

ich werd's versuchen und berichten, ob's geklappt hat.

Danke nochmal,
Hans-Peter

[hps]

Hallo Kurt,

ja, die Methodik ist sehr effizient. Vor Jahren habe ich 4x die Woche trainiert und jetzt 2x. Das Ergebnis ist mehr oder weniger das gleiche. Ich hätte mir gewünscht, dass ich damals mal einen fähigen Trainer gehabt hätte. Aber die sind ja in Studios eher weniger anzutreffen und Kontakt mit Leuten aus der Gewichtheber- oder Powerlifter-Szene hatte und habe ich nicht. Gut, dass ich (aus Zufall) das Forum entdeckt habe!

Hans-Peter (der so langsam wieder Motivation bekommt, im nächsten Jahr 120 Kg BD zu "knacken".)