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GUIDED ARTICLE CRITIQUE: CHANGE OF DIRECTION
In most sports, the participating athlete must be able to rapidly change their direction. In
order to efficiently and successfully change direction, an athlete must depend on their reaction
time, linear speed, lateral speed, acceleration, agility, vertical and multidirectional jump ability.
All of these skills are essential aspects of an athletes ability to perform at a high level. This is
why I believe that the research article Association of Strength and Plyometric Exercises with
Change of Direction Performances is an extremely important part of this course. Change of
direction relys on both total strength and reactive strength, “When training programs fail to
provide a significant increase in COD performance, it is often due to neglecting the task specific
demands of the COD (Falch, et.al 2020)”. Within this course we will learn how to successfully
design a training regiment for an athlete that will meet the demands of not only the sport, but all
aspects of the sport, COD included; while still matching the skill level of the athlete.
The topic if interest for this study is wether or not performance and muscle activation in
strength tests could account for increased performance and muscle activation in force dominant
COD, and velocity dominant COD. Often, it is the lack of specificity in movements that cause a
program or regiment to fail in its’ attempt to increase an athletes COD performance. COD is the
athlete’s physical ability, to rapidly exert as much force as possible and accelerate, decelerate,
and re-accelerate in a different direction in as short duration of time. The ability to rapidly
change direction has been found to be a heavily distinguishing factor between the elite and the
sub-elite athlete. In order to to achieve an elite or even sub-elite COD time, an athlete must be
able to generate a large amount of maximal strength, reactive strength, and power of the lower
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limbs. Because of this fact, strength and plyometric movements are often utililized as training
interventions to develop lower limb power, reactive strength, and maximal strength.
This study used 23 experienced male football players. All 23 male subjects were right-foot
dominant, which according to current research, is defined as the preferred foot for kicking a ball.
This expirement used a within-subject design, where all participants in one occasion performed a
battery of COD, plyometric, and strength tests. Prior to the testing, the participants were required
to complete two full days of familiarization, where the subjects practiced the COD, plyometric,
and strength tests in an attempt to decrease the chance of any subject having their results altered
by the learning effect. Following an identical protocol to the day of familiarization, the subjects
established a 1RM, and performed several COD tests after warming up. The COD testing battery
consisted of 1 rep each of a 45 degree, and 180 degree turn, with a 4m and 20m sprint approach.
All CODs were designed to require left turns as to ensure that the right foot (dominant side)
would be performing the COD step.
With the COD tests being performed first, the strength and plyometric were randomly rested
afterward. Proper performance technique in a few different random tests was controlled using 3D
modeling. Some of the tests performed were the Unilateral quarter squat, bilateral parallel squat,
and lateral squat, also performed was the skate jump, unilateral countermovemement jump, and
the drop jump.
The researchers used electronic timing gates to record the participant times during the
COD tests, reactive strength index (RSI) and jump height were measured using an infrared
optical contact grid, muscle activity was recorded using EMG.
None of the strength tests had any significant correlation with COD performance, drop jump
performance had a significant correlation with the 20m 45 degree COD, the countermovememnt
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jump had a significant correlation with the 4m 180 degree and the 20m 45 degree COD.
However it was found that the skate jump held a significant correlation with all COD
performance.
The purpose of this study was to find the relationship between performance measures in
strength and plyometrics, and force and velocity dominant COD’s. This study also aimed to look
at the comparison of muscle activity of different exercises with that of the muscle activity of the
COD’s.
According to past research, there were high expectations for the correlations between
plyometric performance and COD. However I believe that the researchers were a bit shocked
when they found very little correlation between lower limb strength and COD performance. In
fact, none of the strength tests recorded a significant correlation with COD performance (r <
0.41, p > 0.08). This possibly could be because the researchers were testing and recording
maximal effort strength, rather than dynamic effort strength. Moving heavy weight, slowly may
not transfer to COD performance, in this case it would have been more advantageous to test the
subjects force velocity. The skate jump however, correlated the most and best with all COD’s.
Possibly because the skate jump is a COD itself (r > -0.49, p < 0.02), when considering that it is
the only lateral/horizontal jump used within the study.
Both hamstring muscles were found to have lower muscle activation in the strength tests
when compared to that of the CODs. The same was found for the adductor longus, gluteus
medius, and gastrocnemius.
There are several limitations that I found when reviewing this article. Firstly I believe that the
sample size is too small, there also should be some dictation reguarding the position groups used,
football players is far too general of a title. Secondly, without knowing how these football
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players have been training in the past, wouldn’t it have been more advantageous to the results, if
the study was conducted over time? To see if a training program that consisted of these
plyometric and strength movements had any correlation on COD performance. In a recent study
by Guo, they used a 6 week balance and plyometric program to test improvement on the COD of
badminton players. The results showed a increase in COD performance in the 5-0-5 test. Another
study performed by Falch they tested the effects of strength vs. plyometric training on COD
performance in experienced soccer players. They found that the plyometric group had a better
COD performance because of the task specific movements used within their training. It seems
pretty clear cut to me that the ability to program and progress the skate jump alone, would be
extremely beneficial to an athlete’s COD performance. The performance level of the athlete is
never mentioned, it would be important to highlight wether the subjects were elite or sub elite
level athletes.
In conclusion, the plyometric tests performed showed that there indeed is a correlation
between plyometric movements and both force and velocity dominant CODs. Strength
movements however, showed that this is little to no correlation to be found. These findings are
only strengthed when considering the EMG muscle activation data, this data also shows that
plyometric exercises more likely to share more of a similar level of muscle activation in the
CODs than strength training. This research article is perfect for this course, through the use of
EMG and a slew of other testing measures, these researchers have pinned down several sure fire
plyometric exercises that directly correlate with COD performance. Both the skate jump, and the
drop jump are now proven to be beneficial. As a Strength and Conditioning Coach, this is
extremely important, if I know there is a strong correlation between these movements and an
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References
Chandler, T. J., & Brown, L. E. (2019). Chapter 17. In Conditioning for strength and human
performance (pp. 432–477). essay, Routledge.
Falch, H. N., Rædergård, H. G., & van den Tillaar, R. (2020). Association of Strength and
plyometric exercises with change of direction performances. PLOS ONE, 15(9).
https://doi.org/10.1371/journal.pone.0238580
Guo, Z., Huang, Y., Zhou, Z., Leng, B., Gong, W., Cui, Y., & Bao, D. (2021). The effect of 6-
week combined balance and plyometric training on change of direction performance of
Elite Badminton Players. Frontiers in Psychology, 12.
https://doi.org/10.3389/fpsyg.2021.684964
Rædergård, H. G., Falch, H. N., & Tillaar, R. van. (2020). Effects of strength vs. plyometric
training on change of direction performance in experienced soccer players. Sports, 8(11),
144. https://doi.org/10.3390/sports8110144
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