Dr Mel Siff Blog

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You may recall my referring before to Dr Tom McLaughlin’s book on the
biomechanics of bench pressing (“Bench Press More Now”) — well, here is an
interesting paper that he and a colleague wrote on the biomechanical
differences between novice and expert bench pressers.

————————

Madsen N, McLaughlin T

Kinematic factors influencing performance and injury risk in the bench press
exercise

Med & Science in Sports & Exercise. 16(4):376-81, Aug 1984. Read more…

It is often stated that a muscle lengthens, but all shortening and
lengthening takes place relative to some starting position. In functional
anatomy, the length of a contracting muscle is invariably measured relative
to its resting, unactivated length. During concentric action, the joint angle
decreases while the muscle contracts; during eccentric action, the joint
angle increases while the muscle contracts. During isometric action, the
joint angle remains the same, even though the muscle is contracting.

Isokinetic action does not take place under any natural daily life
conditions, but is the result of movement that is controlled by a special Read more…

We will all have tried to walk as fast as possible without actually running
and discovered that each of us reaches a certain limit speed. This walk-run
transition phenomenon has been studied in biomechanics for many years, but
it has not been extrapolated to the world of similar transitions involving
other movements.

Let us examine the possibility of doing so in the world of strength and
sports training. First we need to recall the process known as
co-contraction, which involves so-called agonistic and antagonistic muscles
acting throughout a given movement to control the movement pattern and
characteristics. In fact, some of you who have been discussing the
interaction of quadriceps and hamstrings have been alluding to this process.

However, this process cannot take place in the same way under all conditions.
In particular, if a movement is explosive or ballistic, this might involve
the ‘agonistic’ muscles (or ‘prime movers’) in contracting powerfully during
the earliest stages of the action and projecting the limb towards its end
point. The ‘antagonistic’ muscles have to stay out of the action for most of
the time because if they were activated, they would stop the movement or
cause muscle rupture. Thus, they only ‘kick in’ towards the end of the
movement to limit joint range and prevent dislocation.

In other words, there are two classes of movement: cocontractive and
ballistic. If one is to reduce HIT and ‘Superslow’ training to basics, then
it may be seen that these schools of training thought support the former and
denounce the latter, in clear contradiction of the fact that a considerable
amount of animal movement involves ballistic action for enhanced efficiency,
energy conservation, speed of action and safety. The EMG aspects of these
different types of movement are discussed in Basmajian (“Muscles Alive”).

Now let us return to the walk-run situation. Here we will note that walking
relies heavily on cocontraction, but when a certain transition locomotion
speed is exceeded, running takes over and ballistic action dominates. We
will observe the same situation arising in strength training. The faster you
try to execute a movement, the more the action has to implicate ballistic
processes, and the prestretch, neural facilitation and elastic energy
phenomena which underlie ballistic processes.

This is why it can be totally inappropriate and misleading to compare the
same exercise under different speeds (and accelerations) of movement. This
also yields clues as to the differences between ordinary fast movements
(‘plyometric drills’) and true ’shock’ method types of so-called
plyometrics, which we discussed some weeks ago.

If we apply this information to the ‘Romanian Deadlift’, we will now notice
that there are at least two different ways of executing this movement: one
with the bar starting from a static position below the knees and the other
from a ballistic, prestretched starting position in which the bar starts
above the knees and is ‘bounced’ below the knees to provide strong
’stretch-shortening’ activation.

If we compare the slowly executed conventional prone reverse hypers with the
variant used by Louie Simmons (the load is swung back and forth using
powerful ballistic action), we will appreciate that is comparing apples and
oranges. The ballistic form is more like sprint running and the
conventional slower form is more like strolling. If you wish to develop
explosive capabilities in the squat, clean pulls and snatch (and in
sprinting), then guess which form is more appropriate?

There are many more applications of this information on Slow-Fast Transitions
(such as the very simplistic bodybuilding concepts of temp counting and
training), but the above should suffice to enable you to apply this
information elsewhere for yourselves.

Dr Mel C Siff

<< I’m just a simple coach, but I’ve seen dramatic, immediate improvements in
static posture (using a plum line assessment, such as the type described in
Kendall’s PT textbook) with several soft tissue techniques, particularly
Active Release Treatment Techniques.>>

***Interestingly, Kendall’s methods recently have come in for a great deal of
criticism in many physical therapy and biomechanics circles, especially since
they have been based upon some rather thin research involving testing of
isolated joints under static conditions. I am sure that Barrett Dorko could
supply some references on this.

‘ACTIVE RELEASE’ TECHNIQUES

For those who may not know, ‘Active Release Treatment’ (ART) is a collection
of techniques simply given a new name by chiropractor Michael Leahy from
physical therapy (especially Janet Travell’s work on trigger point and
myofascial release), classical massage, Shiatsu, osteopathy and other
well-known tissue therapies.

I wrote an Internet review of its origins and requested any so-called ART
practitioners to furnish any research or peer-reviewed clinical studies which
showed categorically that ART is equal or superior to other therapies being
used to treat the same type of musculoskeletal problem. All that I received
was a series of the usual indignant letters quoting more anecdotal evidence,
none of which even vaguely controlled for the possibility of a placebo
effect.

Most significantly, I even received an offended letter from Michael Leahy
himself, who admitted that there was nothing original about ART, but that he
had just formalised it into an organised system with his own certification
scheme. In essence, he felt that I had not adequately recognised ART as
highly effective therapeutic system and that I should give it a fairer
hearing.

He also iterated anecdotally the great success enjoyed by ART, so I wrote
back stating that it would be a pleasure for me to write (for all the
Internet groups to which I belong) another article on ART if he could kindly
send me a list of references proving all claims that have been made for its
efficacy with respect to other standard methods of physical therapy, medicine
and chiropractic. Most significantly, he failed to reply and I have not
heard from him since.

Anyway, I was referred to websites such as the following by other ART
practitioners:

http://www.chiropractic-sports.com/reference/ART.HTML

Here is an interesting extract from this site:

<The skill of application of ART is highly dependent upon the practitioner’s
knowledge of anatomy, biomechanics and most importantly touch. One must not
confuse terminology related to performing ART. Often when a practitioner is
asked if they do ART, they respond by saying “yeah I do that, it’s like
myofascial release right?” You can tell immediately that they are not
properly trained and you can be assured you will not be getting ART. To be
certified in ART, the Doctor or therapist MUST have completed a course in ART
and passed a national certification exam.>

*** The implication immediately is that ART is somehow superior to Janet
Travell’s myofascial release and trigger point work, as well as its
simplified borrowings in the form of Bonnie Prudden’s ‘Myotherapy’, a claim
which is totally unsubstantiated by research or clinical studies. There are
just as many therapists who claim equally impressive success to ART.

The reference to a “national certification exam” has nothing to do with any
medically recognised national qualification. ART certification is a private
commercial scheme administered by Leahy. You do not have to be certificated
in ART to practise its techniques because all of those techniques existed in
other therapeutic systems way before ART was conceived as a separate
therapeutic modality. The name may be protected, but all of the techniques
may be used by any other therapist who is familiar with them.

The above extract also mentioned that the success of ART depends “most
importantly on….touch”, in other words on certain individual skills of the
therapist. This is true of all therapies. I have little doubt that Leahy
probably enjoys numerous successes with ART, not simply because of the
system, but because of his special personal touch and subjective qualities.
I have personally witnessed healing success with Therapeutic Touch,
shamanism, magnets and several other ‘complementary’ therapies, BUT this does
not constitute valid scientific proof of their effectiveness. Such
observations do not rule out the possibility of a strong placebo effect.

This does not mean that I would ever state that someone should not use any
therapy because of lack of scientific validity. As one of my physics
professors one said to me about a tedious and lengthy mathematical method
that I had unhappily used to solve one of the problems that he set for us:
“If it works, use it!”. I always felt awed when I saw how craftily and
succinctly many of the world’s truly great physicists solved problems, and I
felt that I should at least be a bit more elegant with my own solutions. My
physics prof put everything into a more realistic light with that remark
which I have remembered some 35 years later.

By all means, let anyone use ART, Therapeutic Touch or what they will, but
please don’t let them make unsubstantiated claims about clinical efficacy or
underlying mechanisms if they do not exist. Rather say what the TV detective
hero, Hunter, said about his method of solving criminal problems: “Works for
me!”

STRENGTH TRAINING & POSTURE

<<The same goes with strength training exercises. I realize that there are
many studies which say that strength training does nothing to improve
posture, but again and again I’ve seen athletes demonstrate dramatically
improved static posture after participating in a strength training program.>>

*** I agree with you on this score, but it may be that the improvement does
not necessarily have to do with increases in strength, but with other
processes that resistive training may mediate, such as disinhibition of
certain muscle actions, facilitation of other muscle actions, post-exercise
relaxation, overflow, enhanced proprioceptive sensitivity, conditioning of
certain reflexes or other neurally based facilitatory processes. So, while
strength increase may not always be the direct cause of postural improvement,
other processes involved with strength training may be responsible for
causing definite change. There is some interesting scope for research here.

Dr Mel C Siff

<<….. I stated that Heavy weights are far more dangerous than moderate
weights in children, and many studies have shown that you can get BETTER
gains…several of the studies that you, yourself have referenced. >>

*** It would be more accurate to restate everything that has been written or
implied about the risks of weight training and any other sports in this way:

“Greater forces, powers and work loads are potentially more dangerous than
moderate forces, powers and work loads, especially if the patterns of
movement are complex and involve the movement of implements that can readily
produce deviations from safe conditions.”

This more accurate statement is necessary because moderate weights can be
accelerated more rapidly than heavier loads or in ways that deviate further
form the body than heavy loads. This means that movement under these more
modest conditions can produce much greater forces on the body, which is
precisely what we are trying to minimise. We must not fall for the fallacy
that training with heavy weights necessarily imposes greater forces and
torques on the body. This simply is not true.

>>Of course, in both cases, the shock is transmitted via the legs to the
>>spine and rest of the body, but even then, the twin who is executing non-
>>maximal sporting actions is exposed to a force that is some 2.5 times
>>greater than that experienced by his brother who is squatting with nearly
twice
>>bodyweight. It does not matter where or how contact with the ground is
>>made the force is still transmitted to the whole body.

Again, not what I was talking about. I am talking about specific point of
pressure. Each step is slightly different than every other during a run and
the point of pressure changes. In, for example, a squat, the feet are
stationary and the point of pressure does not change.

*** In terms of biomechanics there is no such thing as a “point” of pressure.
Pressure is defined as Force per unit Area (P = F/A) and a point is defined
as an imaginary location which occupies no area or space. In other words, we
would be dividing by zero and pressure at a point would be infinitely large.
Putting that pedantic issue aside, yes, the locus of contact of the foot with
the ground changes during each stride, but so it also does in powerlifting.
The foot does not have to leave the ground for the line of action of the
centre of gravity of the effective load to move during a squat. “Centre of
pressure” studies like this have been carried out for many years on lifters
and runners and the centre of pressure does not remain in exactly the same
region during squats or pulls.

The force transmitted to the rest of the body has nothing to do with the
locus of the centre of pressure. No matter where the force acts on the foot,
it is transmitted to the rest of the body a fraction of a second later. And
the shock wave or impulse is then imposed on ankle, knee, hips, spine and so
forth.

<<Also a review of basic biomechanics, if you graph the vectors from a ground
reaction force in running and a squat (using squat as an example…don’t
mean to pick on it), you will find a significant difference in the
vectors…namely the weight is acting from a Top-down direction rather than
strictly a ground reaction force.>>

*** What you are trying to point out is that the force may be broken down
into various horizontal and vertical components (to be more complete, we
should also add rotational components, which are often dominant features in
the causation of lower extremity injury). In my earlier letter I was
referring to the vertical ground reaction force (I even mentioned reaction
forces) and it was THIS force that was far greater during running and jumping
than squatting. Sorry, there is no way out of accepting that the vertical
reaction forces imposed during many traditional school sports routinely
exceed those encountered in even heavy powerlifting and weightlifting. Visit
any biomechanics laboratory and check for yourself.

But now that we are on the issue of components of force, let us focus for a
moment on rotational components or torques about various joints in the body.
It is these types of action which cause a huge number of injuries in daily
life and typical school sports, far more than the vertical reaction forces
encountered in either light or heavy lifting. Thus, when a footballer,
soccer player, baseballer or basketballer plants a foot, turns suddenly,
accidentally allows the ankle or knee to twist excessively, the resulting
torque produces the host of injuries that all of us see daily in sport -
ruptures of ACL, collateral ligaments, menisci – and in the upper body, we
have the infamous rotator cuff syndrome.

So, if we are to make any cautionary comments about participation in sport,
let’s simply make a blanket statement about all sports and impress on
everyone the dangers of excessive magnitude and duration of force and torque
on the young or old body. Let us talk about what really causes the
problems, namely FORCE, TORQUE and WORK LOAD (Volume), not magnitude of load
alone.

While magnitude of load can produce large forces, etc, this is also true of
light loads, especially light loads acting over a long lever (e.g. as in
throwing and hitting). I know that this requires more sophisticated
education, but at least it does not produce generations of misguided, but
well-meaning coaches, parents and athletes.

<<once again, Mel…I am not comparing weight lifting to other sports…but
if you really want to, you might want to explain the documented increase in
weightlifting, running and track & field injuries in adolescents over the
last 10 years and the reduction in hockey, football and soccer injuries. I
can’t explain it. >>

***I either own or have read through many of those references that you listed
recently and, while a few referred to some trivial cases of weight training,
not one examined the injury history and patterns of youngsters who had
participated for a few years in Olympic Weightlifting and Powerlifting (where
heavy loads are part of competition). We all agree that poor technique in
any sport, including the lifting sports, is probably a major cause of injury,
there seem to be no references that anyone has produced in NSCA, ACSM or
medical situations which prove that competitive lifting in youngsters causes
a significant increase in musculoskeletal injury, especially if compared with
their peers who have participated in other traditional school sports.

<<We understand, Mel. I’m simply stating that moderation is important and
that we let the general public know that there IS risk and danger associated
with weightlifting, just like other sports. >>

***Fully agree. We must optimise training to suit the INDIVIDUAL
irrespective of age, gender or structure and any sage coach knows that. What
we simply need to do is to create a lot more sage coaches, parents and
athletes.

Dr Mel Siff