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Keith N. Bishop, MS, ATC et al ABSTRACT Eccentric strength training, also
known as negative lifting, has gained favor as a method to train, often
due to the perceived ease of the exercise when compared to concentric or
isometric training at the same load.
Often, delayed onset muscle soreness accompanies an eccentric
training program, which can be considered one of the negative aspects.
Not much research has been performed that investigates how an
eccentric training program can affect concentric strength when assessed
isokinetically. These authors
wanted to find if eccentric training at either 60 deg/sec or 180 deg/sec
would affect the concentric strength of normal individuals, if there were
a difference between the speeds, and if there was a difference compared to
a normal control group. Three groups, each having 15
subjects, were chosen from a Fitness for Life Physical Education class at
Brigham Young University. All
received partial credit for participation in the program, which occurred
3x/week for a total of 8 weeks. The
mean age of the subjects was 19.9 years, none had a history of lower
extremity problems that would affect the study, all used their dominant
limb for the study, and the KIN-COM was used for assessment and training. Subjects had to meet a minimum
force during the eccentric training or else the machine would stop and not
count that particular repetition. This
minimum force was increased throughout the program. At the end of the study period, no
increases were seen for concentric quadriceps strength at either speed for
any of the groups either prior to the study or even after the study.
The eccentric hamstring increased significantly for both groups
when compared to the control group, but there were no differences between
the groups. Soreness ratings
were lower for the higher speed group, most soreness occurred the day
after training, and after the first week, soreness was no longer an issue. The data indicates that eccentric
training is an effective means for strengthening the hamstrings but not
the quadriceps, and the speed used does not appear to be a factor in the
strength gains. One possible
reason for the lack of strength gains for the quadriceps could be that
these were all normal individuals, and may have already maintained full
strength. The hamstrings,
however, may have been weaker as they often are in normal populations.
A deeper review of the data revealed that those who had weaker
musculature at the onset of the study showed greater strength gains
throughout the length of the program, which may simulate more what would
be seen with a patient. COMMENTS This is one of the articles that
developed my therapeutic training and personal training right at my time
of graduation from PT school. Since
the subjects chosen were volunteers from a physical education class, I
realized that they might not be giving their full effort, and thus the
reason for no quadriceps increase. Once
I read this article, I began incorporating negative training into many of
my patient’s regimes. ACL
patients, especially those either lacking one or who underwent a hamstring
autograft, are trained on standard equipment with a “up with two, down
with the bad” system, so that the muscle can handle an adequate
concentric load, and then take the entire load for an eccentric return.
It works great, and may be one of the reasons that we achieve more
than 100% strength on our hamstring strength exams, which other studies do
not. I use the same technique for those
with weak, non-functioning, or under-functioning rotator cuffs.
They cannot sit and push a weight straight up into the air without
help, but can control an eccentric return, which I capitalize on.
Performing “2 up, one down” with the quads is a little tougher,
and can exacerbate a hidden patellofemoral problem unless one is careful. I have also incorporated this
training into my own personal weight lifting and have seen significant
gains. The last 3-4 reps of
biceps curls, which I cannot perform alone, are “helped” during the
concentric phase by my other hand, and then the arm is allowed to
eccentrically return slowly on its own. I do the same for triceps, and
would do the whole body if it did not require a spotter.
This is the reason why I avoided the isokinetic home weightlifting
device that came out 10 years ago (by NordicTrack I believe).
The machine used a cable attached to an isokinetic simulator, but
the machine was not able to provide any eccentric return.
This basically takes away 60% of your force generation during a
training program, which is not acceptable.
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