Recently an article “Toward an Understanding of Power” was written in the
NSCA’s Strength & Conditioning Journal (Oct 1999: 34-35), which contained
some curious biomechanical definitions and calculations. Here are a few of
them for your interest:
1. “For instance, in cleaning a weight, the velocity of the bar is equal to
its speed and the upward direction in which it moves.”
2. “Strength times speed equals power”
3. Work = force x distance, where Force = Mass lifted,
Distance = gravity x height of pull
Gravity = 9.8 m per sec squared
The article then used the above definitions to calculate power and hence
compare the power generated in the Weightlifting clean and the Powerlifting
deadlift, thus:
Power = Work/Time to execute lift
….but did not distinguish at all between mean power, power at any instant
and peak power during the lifts concerned (deadlifts and cleans).
Would anyone else care to comment on the material which I have quoted above?
In a letter to the editor of the journal, I stressed that one cannot casually
equate velocity (a vector) and the speed (a scalar) ,especially in
non-linear dynamic lifts, and that work is not simply Force x Distance in a
system in which force and direction of application of the force is changing
throughout the movement. I also pointed out the obvious errors in equating
Force with Mass and in defining Distance = gravity x height of pull (all of
this is nonsense).
The author of the article simply replied in the Aug 2000 issue of the same
Journal that:
” I had Dr L, chairman of the math/physics department at …….. University,
review the formula along with the comments. Dr L said that my calculations
are correct…… In trying to make the formula more understandable to
people with no background in math and physics, I had added a few extra words
for clarification purposes, which to a purist was not acceptable.”
Would anyone care to comment on this response, as well?
What concerns me is that this NSCA (National Strength & Conditioning Associati
on) publication reaches tens of thousands of its members all around the
world, many of whom do have at least 4 year degrees in physical education,
kinesiology, science, physical therapy and related fields. The NSCA
administrates and awards the CSCS (Certified Strength and Conditioning
Specialist) qualification and Personal Trainer certification. It is widely
regarded as the definitive source of strength training information for
strength coaches and includes many highly qualified scientists in its ranks,
yet it seems quite contented to allow seriously misinterpreted scientific
information to reach its members.
The NSCA is not unique in this regard. Many other certifying bodies and
training organisations in the strength and fitness realm reveal a similar
attitude that their members “are not scientists” and need not be given a
rigorous background to the simplified concepts that are taught to them.
Some lecturers on the popular fitness circuit have casually confused torque,
moments, couples, force-couples and many other standard mechanics
terminology, yet, when I have tried to point out their errors, they have
simply responded with personal attacks. In a different way, the author of
that NSCA article (a prominent strength scientist in the USA and author of
several books) totally refused to accept that his definitions were
incorrect and misleading.
It seems as if many authorities in the fitness and
strength world consider that they never make mistakes and, if they do, they
should never admit them. Their standard method of handling anyone who
comments on their errors is to attack the messenger very emotively and to
totally ignore the incorrectness of the message. And so, the status quo
continues!
While popularisation of difficult concepts is vital for the general public
and some folk, such as the late Carl Sagan were masters at this, are these
organisations and lecturers not doing their members, clients and the
strength/fitness professions a grave disservice? Is there any solution to
this problem?
Dr Mel C Siff