This news item posted on another listserv may also be of interest here.

<< High-load Exercise may Damage the Knees 

April 24, 2000   NEW YORK (Reuters Health) -- Pressure on the knees during 
high-intensity exercise that is often a routine part of gym training among 
young athletes may damage knee cartilage and lead to the development of 
osteoarthritis later in life, according to researchers.  . . . . . 

After performing the leg press exercises, knee samples were taken from the 10 
rats studied. Rumi and his colleagues found that articular cartilage damage 
was more than twice as high among the rats in the exercise group than among a 
group of rats of the same age who had not exercised. The researchers said 
that the results raise questions among orthopaedic surgeons about the 
relative safety of exercises commonly practiced by young athletes -- many of 
whom have been shown to develop knee cartilage damage that is more typically 
found in elderly adults.>>

***This study raises several questions:

1.  Were the knee samples taken shortly after exercises or after several 
months or years  to ascertain whether the acute changes in articular surface 
became chronic or simply represented a stage in eventual adaptation?  Many 
studies have shown that acute muscle and soft tissue soreness is associated 
with the breakdown and reconstitution of the soft tissues, so these acute 
changes are not at all unusual.   All that this researcher may have disclosed 
is one of the early stages in physiological adaptation to different types of 
activity.  It is entirely misleading to extrapolate findings from an acute to 
a chronic situation.

2.  How does this study relate to other studies which show exactly opposite 
findings, namely that pronounced joint deterioration is found among those who 
do not exercise regularly or among those who do minimal impact types of 
training.  For instance, a biomechanics colleagues of mine, Dr Mark 
Swanepoel, and senior staff at universities in England discovered that 
osteoarthritis was more prevalent among those who did not impose regular 
impulsive loading on the joints. 

In his work, Dr Swanepoel reported  that "joints that are subjected to heavy 
impacts such as the ankle, are relatively free from osteoarthrosis in old 
age, and those that are subjected to much lower loading experience a greater 
incidence of cartilage fibrillation and osteoarthrosis.  In fact, as one 
progresses up the lower limb, from the ankle, to the knee, on to the hip, and 
then to the lumbar apophyseal joints, so the extent of fibrillation increases 
at any given age.  The reason appears to be that the cartilage of joints 
subjected to regular ‘peaky’ loading with relatively high joint contact 
stresses, is much stiffer and better able to endure the odd exceptional load, 
than softer cartilage that is lowly loaded.  (see Siff M C "Facts & Fallacies 
of Fitness"  2000, pg 57)

http://24.16.71.95/SPORTSCI/JANUARY/textbooks_by_m_c_siff.htm

He concluded that "Healthy cartilage is cartilage that is subjected to 
repetitive, physiological loading regularly, and this  includes full proper 
joint motion during exercise.  Of course, impact loading should be built up 
gradually, but there is nothing bad about  impact loading per se - cartilage 
‘loves’ to be loaded properly, and  it is the cartilage of the ankle that is 
least subject to  fibrillation."

Once again, Reuters News service should offer a more complete summary of 
findings or at least have different scientists comment on what they are about 
to write, otherwise we are soon going to have a generation that is only going 
to do any exercise that takes place as slowly as possible for as short a time 
as possible, in only one short set, administered by coaches who don't 
mentally stress anyone, in an environment at just the right humidity and 
temperature, followed by lying supine on a specially designed couch with a TV 
set on the ceiling to prevent any lumbar spinal flexion and psychological 
counselling for any mental stress caused by the exercise.  

Later we might reach the stage where ergonomic spectator seating will be 
provided so that humans can simply watch modern sporting gladiators doing all 
the dangerous activities that cardiovascularly biased scientists have 
identified - in other words, a sort of latter day Rome where only the 
specially trained, the youthfully misguided and victimised take part in 
sport.    And these folk will only be allowed to exercise because orthopaedic 
specialists, chiropractors, athletic trainers, chemists and allied sports 
support professionals will still be able to find some business!

Whoa!   I have just realised that most people are already just sitting and 
watching sport instead of taking part - maybe I was asleep for a few decades 
while I wrote about my predictions for the future :)   My niece who is in the 
Special Forces program here in the USA informed me that the drop out rate of 
young MEN recruits there is well over 60 percent during the first few weeks 
of intake, so maybe the future is already here.

Dr Mel C Siff
Denver, USA
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