wfs@mgweed.UUCP (08/02/83)
* Isokinetic Exercise(Part 1) *
A training called isokinetic exercise; how does this differ from
weight machines-and how effective is it ? A Harvey Kurland, M.S., is
Director of Physiology at the National Athletic Health Institute of
Inglewood, Cal.,has extensive expeirence in boxing, aikido and tai chi
chuan, and has written numerous articles on health, fittness and
sports medicine, of which I am presenting in several parts.
Isokinetic exercise is a recent development. Isokinetic devices
(also known as accommodative resistance devices) are currently in use
for exercise and testing. These devices keep the velocity of the
exercise constant by controlling the speed of the device's lever arm.
This is done by electromechanical brakes, hydraulic systems or
inertial devices. An isokinetic device is made to move at a pe-set
speed, no matter how much force is used. Holding the velocity of
exercise constant allows the exerciser to maximally load his muscles
at all points within the range of motion. This is in contrast to the
use of weighted machines which maximally load the muscle at only one
point(known as "The sticking point"). Isokinetic devices can be
ajusted so that the lever arm moves quickly. This allows the exerciser
to train at speeds approaching sport movement speed-while maximally
loading his muscles. this is different than using light weights and
moving quickly. Indeed, to derive the most benefits from classical
weight training exercises there must be strict adherence to correct
technique with the speed of movement being controled. Developing too
much momentum in classical weight exercise lessens their
effectiveness..............(Cont'd. in Part 2)wfs@mgweed.UUCP (08/10/83)
* Isokinetic Exercise(Part 2) *
This limits the speed of muscular contraction and the learning
effects produced by high speed exercise. Because an isokinetic device
can be adjusted to very fast contraction speeds, however, it may be
possible to influence one's athletic performance by training at speeds
which are closer to those of the athletic technique. This adheres to
the principle of specificity in training. Studies have shown that
training at high speeds will increase the torque developed at those
speeds; training at slower speeds does not effectively increase the
production of torque at those speeds. High speed exercise may be of
signal benefit in training. Another advantage of isokinetic exercise
is that it produces much less muscle soreness. This is thought to be
due to the fact that isokinetic exercise involves only concentric
(shortening) contractions where only "positive" work is done. It does
not envolve eccentric (lengthening) contractions or "negative" work,
which is thought to induce muscular soreness. This is, however, a
drawback to those individuals who want to do negative exercise
training! Isokinetic devices are also used for testing muscle
strength. Specific muscle testing allows us to check the balance
between antagonistic muscle groups and contralateral muscle groups-
comparing the left and right quadriceps, for example. In this way,
imbalances can be spotted and specific training regimes can be devised
to correct the imbalance. This is crucial to rehabilitation programs,
as well as to injury prevention. In contrast, muscular strenght
testing by lifting weights, which is a more classical approach, is
fraught with problems. While calibration in the one repetition maximum
method is precise, lifting extremely heavy poundage can lead to
injury. Technique is also a factor. For example, a heavy clean and
jerk involves more than sheer strength: balance, flexibility and
coordination are important factors.......(cont'd. in part 3)wfs@mgweed.UUCP (08/12/83)
* Isokinetic Exercise(Part 3)Final *
In training, isokinetic or accommodative resistance devices have
been found to produce strength increases similar to those derived from
weight machines. In studies performed personally, I have NO
significant difference in results measuring the increase of leg
strength that compare hydraulic accommodative devices to variable
resistance weight machines. Isokinetic devices can be highly
effective in a circuit training format of 20 seconds of work
followed by 20 seconds of rest with the standard three sets of six
to 20 repetitions, depending on the speed setting. Or one can try
"power" workout where maximum reps are performed until 50 percent of
the maximum torqueis reached due to fatigue. The latter technique
"pumps" the muscle and will also work the practitioners specific
muscular endurance. This approach has been found effective by athletic
trainers for physical rehabilitation.
END