Eccentric overload training in team sports

“Eccentric Overload Training in Team-Sports Functional Performance: Constant Bilateral Vertical vs. Variable Unilateral
Multidirectional Movements” by Gonzalo-Skok O et al.
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Note. This article will be published in a forthcoming issue of the
International Journal of Sports Physiology and Performance. The
article appears here in its accepted, peer-reviewed form, as it was
provided by the submitting author. It has not been copyedited,
proofread, or formatted by the publisher.
Section: Original Investigation
Article Title: Eccentric Overload Training in Team-Sports Functional Performance:
Constant Bilateral Vertical vs. Variable Unilateral Multidirectional Movements
Authors: Oliver Gonzalo-Skok1
; Julio Tous-Fajardo2,3
; Carlos Valero-Campo1
; César
Berzosa1
; Ana Vanessa Bataller1
; José Luis Arjol-Serrano1
; Gerard Moras3
and Alberto
Mendez-Villanueva4
Affiliations: 1
Faculty of Health Sciences, University of San Jorge, Zaragoza, Spain.
2
Department of Strength and Conditioning. Chelsea FC, Cobham, England. 3
Sports
Performance Lab. INEFC Barcelona, Spain. 4
ASPIRE Academy for Sports Excellence, Doha,
Qatar.
Journal: International Journal of Sports Physiology and Performance
Acceptance Date: November 7, 2016
©2016 Human Kinetics, Inc.
DOI: http://dx.doi.org/10.1123/ijspp.2016-0251

Title of the Article:
Eccentric overload training in team-sports functional performance: constant bilateral
vertical vs. variable unilateral multidirectional movements
Submission Type: Original Investigation
Oliver Gonzalo-Skok1
; Julio Tous-Fajardo2,3
; Carlos Valero-Campo1
; César Berzosa1
; Ana
Vanessa Bataller1
; José Luis Arjol-Serrano1
; Gerard Moras3
& Alberto Mendez-Villanueva4
.
1
Faculty of Health Sciences, University of San Jorge, Zaragoza, Spain.
2
Department of Strength and Conditioning. Chelsea FC, Cobham, England.
3
Sports Performance Lab. INEFC Barcelona, Spain.
4
ASPIRE Academy for Sports Excellence, Doha, Qatar.
Address correspondence to:
Oliver Gonzalo Skok, PhD
Universidad San Jorge (USJ)
Autovía A-23 Zaragoza-Huesca Km. 299
50830 Villanueva de Gállego, Zaragoza (Spain)
Phone: (+34) 976 060 100; Fax: (+34) 976 077 582
Email: ogonzalo@usj.es
Preferred Running Head: Vertical vs. Multiplanar Eccentric Training
Abstract word count: 249 words
Text-only word count: 3961 words
Number of figures: 2
Number of tables: 1
DownloadedbyUniversityofCalgaryon12/14/16,Volume0,ArticleNumber0

Abstract
Purpose: This study analyzed the effects of two different eccentric overload training (EOT)
programs, using a rotational conical-pulley, on functional performance in team-sports
players. A traditional movement paradigm (i.e., squat) including several sets of one bilateral
and vertical movement was compared to a novel paradigm including a different exercise in
each set of unilateral and multidirectional movements. Methods: Forty-eight
amateur/semiprofessional team-sport players were randomly assigned to an EOT program
including either the same bilateral-vertical (CBV, n=24) movement (squat) or different
unilateral-multidirectional (VUMD, n=24) movements. Training programs consisted of 6 sets
of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) x 6-10 repetitions with 3-min of passive
recovery between sets and exercises, biweekly for 8-weeks. Functional performance
assessment included several change of direction (COD) tests, a 25-m linear sprint test,
unilateral multidirectional jumping tests (i.e., lateral, horizontal and vertical) and a bilateral
vertical jump test. Results: Within-group analysis showed substantial improvements in all
tests in both groups with VUMD showing more robust adaptations in pooled COD tests and
lateral/horizontal jumping whereas the opposite occurred in CBV respecting linear sprinting
and vertical jumping. Between-group analyses showed substantial better results in lateral
jumps (ES=0.21), left leg horizontal jump (ES=0.35) and 10-m COD with right leg (ES=0.42)
in VUMD than in CBV. In contrast, left leg countermovement jump (ES=0.26) was possibly
better in CBV than in VUMD. Conclusions: Eight-weeks of EOT induced substantial
improvements in functional performance tests, although the force vector application may play
a key role to develop different and specific functional adaptations.
Keywords: resistance training, eccentric overload, functional performance, variable training

Introduction
The main goal, which seems to be often neglected, of any strength and power training
program with athletes is to enhance the performance of functional movements relevant to the
sport (e.g., sprinting, jumping or cutting) rather than just increasing power output under
controlled lab conditions. Most training programs for team-sports players have been
traditionally based on those designed for individual sports where weights are constant and
bilaterally lifted overemphasizing concentric and vertical components of the applied force.1
While this conventional resistance training, mainly relying on the selection of bilateral
weight-lifting movements (e.g., squat), has been reported to positively transfer to sport-
related movements such as acceleration,2
sprinting,3
jumping2
and change of direction
(COD),4
most on-field movements require players to produce force unilaterally in
unpredictable and variable contexts with an emphasis on eccentric and multidirectional
components.5
Thus, following the principle of specificity, the inclusion of exercises
containing unilateral, with more eccentric emphasis, multiaxial and some degree of
uncertainty (e.g., perturbations) might be considered in addition to the well-established
conventional paradigm (i.e., mainly repetitive concentric, bilateral and vertical movements).
Despite that more traditional, bilateral training has reported to positively transfer to
unilateral performance6
, the literature on the topic is still scarce and inconclusive and
contradictory results have been found in team-sports athletes.6,7
The importance of applying
force in the desired direction (i.e., vertical, horizontal or lateral) to reach an optimal
movement performance,8
have been recently highlighted, with faster runners showing a
greater horizontal to vertical forces ratio than their slower counterparts.9
Similarly,
professional basketball players exhibited greater mediolateral to vertical forces ratio than
semi-professional players while executing rapid cutting maneuvers.10,11
Such findings imply

that the ability to produce a greater horizontal or mediolateral to vertical forces ratio may be
more important than the overall force production, meaning an optimal force application. This
is supported by literature showing that the ability to produce horizontal force is the main
determinant of sprinting over short distances12
and net horizontal and propulsive impulses are
largely related to the 10-m sprinting performance.13
Therefore, it seems that training
programs including anteroposterior/lateral/rotational force application exercises might be
essential in those sports requiring multidirectional movements even if conclusive evidences
are still lacking.5
In addition, eccentric strength has been proposed as the main determinant for COD
ability14
but the literature analyzing the impact of eccentric overload training (EOT) programs
on this ability is very scarce.5
However, during the last decade EOT programs including
flywheel devices have won many adherents in elite sport training based on both successful
experiences in the professional sport settings15,16
and research findings showing substantial
improvements in both athletic performance (i.e., COD speed/kinetics, jumping and
sprinting)5,17-19
and injury prevention/rehabilitation.17,18,20
Nonetheless, previous reports dealt
mainly with uniaxial movements (e.g., squats, leg curl and leg press) while, as previously
discussed, many actions in team-sports rely on the application of multi-vector forces. In this
regard, the so-called conical pulley (CP) is a device that allows the simulation of sport´s
specific multidirectional movements. Surprisingly, until very recently, the literature was
lacking about the training effects on functional performance prompted through the solely use
of this device.21
However, a combination of exercises performed over the CP, the Yoyo™
Squat, a high-load vibratory platform and other complementary eccentric exercises showed to
substantially improve COD ability.5
Lastly, despite several studies have found that variable,22
differential23
or structural24
training programs are more effective than those including constant/consistent conditions, to

our knowledge no study has tested these approaches including EOT exercises and its effects
on different functional performance tests. Indeed, instead of trying to simulate the
unpredictable and constantly changing situations throughout a match including multiple non-
repeated movements, strength-training programs have traditionally been based on completing
several sets of the same movement.
Therefore, the main aim of the present study was to analyze the effects on a wide
battery of functional performance tests of a unilateral EOT program including
multidirectional movements that varied from set to set (i.e., novel paradigm) in comparison to
a bilateral EOT emphasizing the vertical force component where the same movement is
repeated over several sets (i.e., conventional paradigm).
Methods
Subjects
Forty-eight male semiprofessional and amateur team-sports players (age: 20.5 ± 2.0
years, height: 180.1 ± 6.3 cm, body mass [BM]: 73.2 ± 9.3 kg) volunteered to participate. The
minimum inclusion criteria were: 1) participation into a weekly competition (26
semiprofessionals, 12 amateurs and 10 leisure); 2) weekly training of 6 hours; and 3) no
injury during the last 6 months. Data collection took place after ~6 weeks of a pre-season
period and ~8 weeks of competitive season. Players had 1 to 3 years of resistance training
experience but since none of them had followed a periodized EOT, they were asked to avoid
any lower limb strength training throughout the study. A written informed consent was
obtained from them after the study was approved by the local ethics committee of our
university.

Study Design
Using a controlled and randomized study design (ABBA distribution), participants
were divided into constant bilateral vertical group (CBV, n=24) or a variable unilateral multi-
directional group (VUMD), n=24) based on their ranked physical performance. The training
period lasted 8 weeks and it was carried out in addition to the regular training sessions. The
first week (sessions 1 and 2) was used to familiarize with the exercises and devices. During
the next 7 weeks, subjects trained biweekly (Tuesday-Thursday or Wednesday-Friday).
Prior to the study, tests were analyzed for reliability using the same sample of players
(n=48) whereas one week after the intervention, were repeated to examine the training
effects. Tests included COD sprints over several distances, a linear sprint, unilateral jumps
(i.e., lateral, horizontal and vertical) and a countermovement jump (CMJ). Participants were
asked to not perform any strenuous exercise the day before each test and to consume their last
meal at least 3 h before the scheduled test time.
Procedures
Training intervention
Participants in both groups (CVB and VUMD) performed two weekly additional
training sessions always in the morning (10 AM-12 PM) during an 8-week period. CBV
consisted of 6 sets in one exercise (squats, until thighs were in parallel to the floor with a
predominant axial force vector), whereas the VUMD included 1 set of six different unilateral
exercises: backward lunges, defensive-like shuffling steps, side-step, crossover cutting,
lateral crossover cutting and lateral squat (Figure 1) using a portable CP (VersaPulley, Costa
Mesa, CA; Inertia 0.27 kg·m2
, speed/force ratio level 1 out of 4 and transmission
pulleys/harness setup as shown at figure 1). This speed/force ratio was selected based on pilot
studies where this setting achieved the maximum power output. All the exercises were

executed in the same order in every session. Training load was periodized as follows; wk 1:
familiarization; wk 2-3: 6 repetitions; wk 4-5: 8 repetitions; and wk 6-7: 10 repetitions.
Players were encouraged to perform the concentric phase as fast as possible, while delaying
the braking action to the last third of the eccentric phase. Three minutes of passive recovery
were provided between-sets and exercises. The main researcher controlled every training
session, providing verbal encouragement to each participant.
Functional Performance Tests
Tests were carried out in 2 different days before the training intervention with all
jumping tests administered during the first day and linear sprint and COD tests during the
second day. Sessions were separated by 48 h and took place at the same time of the day (10
AM to 12 PM) to minimize circadian rhythms´ effect.
COD tests
Tests included five (COD10), ten (COD20) or twelve and a half (COD25) meters in a
straight-line and a right- or left-turn of 45º between 4 sticks (height: 1.5 m) placed vertically,
to proceed to the finish line as fast as possible. Time was recorded with photocells (Witty,
Microgate, Bolzano, Italy) with the front foot placed 0.5 m before the first gate. Subjects
executed two trials with two minutes of recovery in-between and the fastest time retained for
analysis. Intraclass correlation coefficient (ICC) was between 0.78 and 0.87 and coefficient
of variation (CV) was between 1.6 and 2.3%.
Speed tests
Running speed was evaluated by 25-m sprint times (0-25 m) (standing start) with 5-m
(0-5 m), 10-m (0-10 m) and 20-m (0-20 m) split times. The front foot was placed 0.5 m
before the first timing gate. The test was performed twice with 3 minutes of recovery. The

fastest time was retained for analysis. ICC was between 0.79 and 0.83 and CV was between
1.5 and 4.8%.
Lateral and horizontal jump tests
Lateral jump (LJ) and horizontal jump (HJ) performance (i.e., distance) were assessed
as described elsewhere.25
Each test (right and left) was performed 3 times with 45 seconds of
recovery, and the best jump was recorded. The variables used for posterior analyses were: 1-
legged right LJ (LJR) and HJ (HJR), 1-legged left LJ (LJL) and HJ (HJL) and the mean of both
limbs (LJpool and HJpool). ICC was between 0.84 and 0.9 and CV was between 3.6 and 4.1%.
CMJ test
Lower limb vertical explosive power was assessed as described elsewhere (Optojump,
Microgate, Bolzano, Italy).5
Each test was performed 3 times with 45 seconds of recovery,
and the best jump was recorded. The variables used for posterior analyses were: bilateral
(CMJb), 1-legged right (CMJR), 1-legged left (CMJL) and the mean of both limbs (CMJpool).
ICC was between 0.91 and 0.96, and CV was between 2.4 and 4.2%.
Statistical analyses
Data is presented as mean ± standard deviation (SD). All data were first log-
transformed to reduce bias arising from non-uniformity error. The standardized difference or
effect size (ES, 90%CI) in the selected variables was calculated using the pooled pre-training
SD. Threshold values for Cohen ES statistics were >0.2 (small), >0.6 (moderate), and >1.2
(large).26
For within/between-group comparisons, the chances that the differences in
performance were better/greater (i.e., greater than the smallest worthwhile change, SWC [0.2
multiplied by the between-subject standard deviation, based on Cohen’s d principle]), similar
or worse/smaller were calculated. Quantitative chances of beneficial/better or
detrimental/poorer effect were assessed qualitatively as follows: <1%, most likely not; >1–

5%, very unlikely; >5–25%, unlikely; >25–75%, possible; >75–95%, likely; >95–99%, very
likely; and >99%, most likely.26
If the chance of having beneficial/better or
detrimental/poorer performances was both >5%, the true difference was assessed as unclear.
Otherwise, we interpreted that change as the observed chance.26
The Pearson product moment
correlation coefficient was used to determine the relationship between different variables.
The following criteria were adopted for interpreting the magnitude of correlation (r) between
tests measures: ≤0.1, trivial; >0.1–0.3, small; >0.3–0.5, moderate; >0.5–0.7, large; >0.7–0.9,
very large; and >0.9–1.0, almost perfect.26
If the 90%CI overlapped small positive and
negative values, the magnitude of the correlation was deemed unclear; otherwise the
magnitude was deemed to be the observed magnitude.26
Results
Participants
Only players who participated in 85% of the training sessions were included in the
final analyses, with 10 out of 48 participants excluded due to injury (during competitive
matches) (n=4), illness (n=3) or lack of interest (n=3). This resulted in 2 groups of 19 players
(CBV: 20.2 ± 1.1 years, 179.7 ± 6.5 cm, 73.4 ± 11.2 kg; VUMD: 20.8 ± 2.6 years, 181.7 ±
5.5 cm, 75.2 ± 7.6 kg) with no substantial anthropometric differences found at pre- or post-
tests.
Changes After the Training Intervention
Substantial improvements were found in COD10L, COD20R, COD20L linear
sprinting, LJR, LJL, HJR, HJL, CMJL and CMJ in both groups compared to the pre-test (Table
I). Furthermore, COD10R and COD20L were also substantially enhanced in VUMD group
whereas CMJR achieved substantial better results in CBV.

Substantial better results were shown in HJL (3.2%, 90%CI: -0.1; 6.3; 76/23/1%) and
COD10R (2.0%, 90%CI: -0.1; 4.1; 79/19/1%) in VUMD in comparison to CBV. A possibly
greater performance was found in LJR (2.0%, 90%CI: -1.9; 5.8; 51/44/4%), LJL (2.3%,
90%CI: -1.2; 5.6; 51/47/2%), HJpooled (ES= 0.25, 90%CI: -0.09; 0.60; 2.2%, 90%CI: -0.8; 5.4;
60/38/2%) and LJpooled (ES= 0.22, 90%CI: -0.11; 0.55; 2.2%, 90%CI: -1.0; 5.6; 55/43/2%) in
VUMD compared to CBV. On the other hand, CMJL (4.9%, 90%CI: -0.6; 10.8; 64/35/1%)
and CMJpooled (ES= 0.20, 90%CI: -0.06; 0.46; 3.6%, 90%CI: -1.0; 8.4; 51/49/1%) were
possibly better in CBV than in VUMD (Figure 2).
Relationships between performance changes
When data for both groups were pooled, very large to almost perfect (r: 0.77 to 0.91)
correlations between individual changes in any linear sprinting variable (0-5 m, 0-10 m, 0-20
m and 0-25 m) were provided. Furthermore, HJL improvement was moderately correlated
with COD25L (r: 0.43) improvements.
Discussion
The present study analyzed the effects on a battery of functional performance tests of
a bilateral EOT emphasizing the vertical force component in just one exercise over several
sets (i.e., conventional paradigm) in comparison to an unilateral EOT with a greater
anteroposterior/lateral/rotational force vector application in a multi-exercise program over
just one set (i.e., novel paradigm). Despite both training programs substantially improved all
tests, the specificity of training adaptation principle mainly prevailed, with CBV group
showing greater enhancements in those tests that predominantly emphasized the vertical
(axial) component (CMJ, CMJR, CMJL) whereas better results were found in multidirectional
force application tests (HJR, HJL, LJR, LJL and COD10R) in the VUMD group. To our

knowledge, this is the first study conducted of this nature. Thus, direct comparisons are not
possible.
The results indicate that both training paradigms induced substantial improvements in
COD performance (Table 1). However, VUMD group obtained more robust adaptations (i.e.,
greater mean ES) in almost all COD tests and a likely better COD10R performance compared
to CBV group. With regards to training contents, only one study has included a similar EOT
program than the VUMD group 5
and while gains were much lower in our study (ES= 0.25 to
0.61 vs. 1.22), players’ age/experience (adults vs. late adolescents), training load distribution
(biweekly vs. weekly) or characteristics (EOT vs. combined EOT + vibrations) and tests
differences in both the number of turns (1 vs 4) and the distances covered can explain the
observed differences.27
In contrast, a recent study has reported no improvements on a COD
test (4 x 100º cut angles during 20 m) after a 6-weeks training program including 5-8 sets of a
single horizontal exercise (front step) on the CP.21
However, besides the fact that no specific
data was provided about key load/exercise settings (e.g. inertia values, speed-force ratio,
transmission pulleys and harness configurations along with the unique exercise technique) we
consider that it is very unlikely to obtain an eccentric overload with the apparently used
setup. Hence, given this argument and the lack of a lateral or rotational force vector
application on the solely employed exercise, the absent of positive results on CODA is
consistent with our training experience with flwheel ergometers.
Despite that pooled data showed “very likely” improvements in COD tests in the
VUMD group, an enhanced COD ability was also observed in the CBV group despite that
only vertical force vector was applied (Table 1). As such, a greater effect in the VUMD with
respect to the CBV group was expected given the apriori more specific force application
during the exercises. It may be that the only common feature between both protocols (e.g.
eccentric overload) emerged as a key factor to produce “likely” improvements in CODpooled at

the CBV group. In this regard, we have found in pilot studies that in more stable exercises
such as the squat, higher power outputs and more consistent eccentric overloads can be
developed compared to more complex exercises such as those included at the VUMD training
program where large errors and fluctuations (e.g. compensatory movement patterns) are
typically observed (unpublished observations). Moreover, improvements in physical
performance tests involving mainly horizontal/lateral force components (e.g., sprint, COD)
have been reported after conventional (i.e., withouh eccentric overload) barbell back squat
interventions.7,21,28
Thus, albeit especulative, the COD improvements observed in the squat
group might be related with the greater neuromuscular and/or mechanical training stimuli
while the VUMD might have benefited from a better dynamic correspondence between
specific unilateral exercises and the testing battery. However, it is important to underline that
in such a short distance as 10 m, post-training times showed how VUMD group surpassed
CBV group in more than 1 meter when cutting with the right leg or near 0.6 m while doing so
with the left leg. These gained spaces appears big enough to obtain a more favourable
position or win a divided ball against an opponent.
Both training programs induced substantial but similar enhancements in linear straight
sprinting with a greater magnitude in shorter distances than in longer distances. Collectively,
these results are in accordance with those found after different EOT programs in team-sports
players (ES= 0.10 to 0.80),5,17,18
whereas traditional vertical-horizontal strength training
programs have reported slightly lower results (ES= 0.19 to 0.24).29,30
Interestingly, the
greatest sprint improvement (ES = 0.84) reported after an EOT has been reported on a 30-m
sprint after a flywheel leg curl training program17
,a device that may offer a higher stimulus
for hamstrings development.31
In this regard, it has been shown how peak hamstring forces
significantly increased as faster speed was achieved32
and those subjects who are able to
produce the greatest amount of horizontal force are also able to highly activate these muscles

just before ground contact and present higher eccentric peak torques, 33
meaning that if longer
distances are covered (i.e., 30-m) more hamstrings involvement may be expected. In contrast,
the exercises performed in the current study seem to better simulate the biomechanical action
presented during the first steps of the sprinting action (i.e., acceleration)34
and hence impact
more on shorter distances as also shown in COD tests. While augmented eccentric hamstring
strength does not always translate into improvements in sprinting performance,35
future
studies should investigate the addition of hip extension and knee flexion (e.g., hamstring´s
kicks5
and leg curl18
) movements in EOT on short and long sprint distance performance.
Lateral and horizontal unilateral jumps has been moderately to largely related to linear
sprinting and COD performance36
and injury risk,37
but to our knowledge, no study has yet
analyzed the effect of a training program on LJ. However, a moderate effect on HJ (ES= 0.64
to 0.65) after a repeated power training in young basketball players has been recently
reported.38
These gains are slightly higher than those obtained by the VUMD group, while
smaller effects were observed in the CBV group. It may be possible that these between
studies’ differences are due to players’ age or training volume performed. Nevertheless,
substantial improvements were achieved in LJ and HJ after both training programs with
VUMD showing more robust adaptations in jumps executed laterally and horizontally
(possibly better results in pooled data [ES in LJ= 0.22; ES in HJ= 0.25] with respect to CBV
group), supporting the force vector application as a key factor to develop specific adaptations.
In reference to unilateral vertical jumps, possibly better improvements were achieved
after CBV in comparison to VUMD training, suggesting again the importance of the
specificity of force application. In contrast and apparently contradictory, bilateral CMJ
improvements were similar after both training methods. Given the higher dynamic
correspondence between the squat exercise and the bilateral CMJ better results were expected
in the CBV group whereas more similar enhancements would be more congruent in the

unilateral vertical jumps due to the permanent use of one leg in VUMD group. It may be that
the substantially lower scores in CMJ at pre-test could in part explain how VUMD group
obtained comparable improvements. Bilateral CMJ gains are in accordance with those found
in different team-sports players after an EOT (ES= 0.58)18
or vertical-horizontal training with
conventional devices (ES= 0.31 to 0.36).29,30
Further studies should also incorporate a battery
of hop tests given its relationship with injury recovery and performance.37
Given the three different combined training variables included in the training
programs it is difficult to ascertain which one could potentially impact more on the results. In
this regard, we were unable to discern between the effects of constant vs. variable practice
since none of the administered tests specifically assessed this factor, and this represents a
limitation of the study. Hence, for future studies a reactive agility or ad-hoc test should be
incorporated for COD assessment as well as the evolution of force/power output and
kinematic parameters during the intervention exercises. With the later approach the potential
relationship between gains in eccentric/concentric mechanical variables and functional
performance could be established. In addition, a more variable/multidirectional jump test
such as the crossover hop for distance may provide useful information on this area. Finally,
the inclusion of traditional exercises (with more concentric emphasis) to combine with the
present exercises (eccentric overload) deserves further studies.
Conclusions
Both EOT programs showed to substantially improve different functional
performance measurements such as CODS, linear sprinting and jumping in different axes.
However, force vector application (i.e., vertical vs. anteroposterior/lateral/torsional) may play
an important role in developing different and specific functional adaptations.

Practical applications
Improving or even maintaining athletic performance in competitive team sport´s
players during the long in-season period is one of the greatest challenges for any committed
coach. Very limited time is available in-between weekly matches to introduce intensive
strength and power training sessions, with a normal frequency of 1-2 units per week. This
fact spurs the quest for more efficient training methods capable of improving a wide variety
of functional abilities while avoiding the carry-over fatigue effects. Many fitness coaches
have included the CP as a usual device on their EOT routines but mainly using a conventional
approach where various sets of the same bilateral/vertical exercise are completed. In contrast,
multidirectional combined EOT approaches have previously shown to be effective and time-
efficient in improving either sprinting, jumping and cutting abilities.5
The present study
showed that 6 sets of either one exercise (i.e., squat) or six different exercises using a CP to
add an eccentric overload were effective at improving either sprinting, jumping and cutting
abilities. However, some of the between-group differences observed suggest that depending
on the player’s needs and functional deficits, it could be of interest to modulate the proportion
of exercises, sort of like setting an equalizer, and tune between
anteroposterior/lateral/rotational or vertical movements, unilateral or bilateral exercises,
variable or constant exercises. For example, those players aiming for advantage in jumping
actions (i.e. heading, rebounding, spiking…) may benefit more from reinforcing their training
sessions with vertical movements. In contrast, for players aiming at enhancing
forward/backward and lateral movements, training sessions should include a higher
proportion of anteroposterior and lateral movements. Rotational movements are surely
needed but care must be taken due to its higher imposed loads,39
hence compensatory

exercises (i.e. core stability and vibratory training) should be added to attenuate such
aggressive loads.
Despite most team-sports movements are performed unilaterally and we suggest
including a greater proportion of one-limb exercises, it may be that the higher and more
stable power outputs associated to bilateral exercises such as squat could be an aid during the
propaedeutic periods. Finally, despite we failed to isolate the impact of variable vs. constant
exercises, we consider variability as a key factor to introduce in a well-sequenced manner. In
our real training programs we start with just one set per exercise followed by two, four or
eight different movements (reps) per set, to end with different movements between the
concentric and eccentric phases. In addition, we agree with Hossner´s structural-learning
proposal24
about the need to link a training content (e.g., movement) in accordance with the
following, in order to find an optimal degree of fluctuations in-between exercises
progressions. In this way, elements such as instability, concurrent vibratory stimuli,
unexpected and anti-phase movements, should be progressively incorporated on each
movement family and direction (e.g. lunges, step-ups, diagonal chops, side-, cross-over,
shuffling, drop or jab steps maneuvers…).
Acknowledgments
We acknowledge Mr Fernando Hernández-Abad for his excellent drawings.

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Figure 1. Functional eccentric overload variable unilateral horizontal/lateral training program
and the corresponding force vector application: A) backward lunges
(anteroposterior/posteroanterior), B) defensive-like shuffling steps
(mediolateral/lateromedial), C) side-step (posteroanterior/anteroposterior), D) crossover
cutting (rotational/anteroposterior), E) lateral crossover cutting (rotational/lateromedial) and
F) lateral squat (mediolateral/lateromedial), and constant bilateral variable training program:
G) Squat.

Figure 2. Efficiency of the constant bilateral-vertical training (CBV) compared to the
variable unilateral multi-directional (VUMD) training program to improve a sprint of 10 m
with right (COD10R) and left leg (COD10L) with a change of direction of 180°, a sprint of 20
m with right (COD20R) and left leg (COD20L) with a change of direction of 180°, a sprint of
25 m with right (COD25R) and left leg (COD25L) with a change of direction of 180°, 5, 10,
20 and 25 m linear sprint time, lateral jump with right (LJR) and left leg (LJL), horizontal
jump with right (HJR) and left leg (HJL), vertical jump with right (CMJR) and left leg (CMJJL)
and bilateral countermovement jump performance (CMJ) (bars indicate uncertainty in the
true mean changes with 90% confidence limits). Trivial areas were the smallest worthwhile
change (SWC) (see methods).

“Eccentric Overload Training in Team-Sports Functional Performance: Constant Bilateral Vertical vs. Variable Unilateral Multidirectional Movements” by Gonzalo-Skok O et al.
Table 1. Changes in performance after a constant bilateral vertical (CBV, n=19) or variable unilateral multi-directional (VUMD, n=19) eccentric overload
training.
Variables
Constant Bilateral-Vertical (n = 19) Variable Unilateral-Multi-directional (n = 19)
Standardized Qualitative Standardized Qualitative
Pre-test Post-test Changes (%) Differences Assessment Chances Pre-test Post-test Changes (%) Differences Assessment Chances
(90% CL) (ES ± 90% CL) (90% CL) (ES ± 90% CL)
COD10R 1.91 ± 0.08 1.89 ± 0.08 1.1 (-0.3; 2.5) 0.25 (-0.08; 0.58) Possibly 60/38/1% 1.91 ± 0.09 1.85 ± 0.08 3.0 (1.5; 4.5) 0.61 (0.3; 0.92) Very Likely 98/2/0%
COD10L 1.90 ± 0.09 1.86 ± 0.09 2.4 (0.7; 4.0) 0.47 (0.13; 0.81) Likely 91/9/0% 1.90 ± 0.10 1.84 ± 0.08 2.9 (1.0; 4.7) 0.54 (0.19; 0.89) Likely 95/5/0%
COD20R 3.29 ± 0.13 3.23 ± 0.12 2.0 (0.7; 3.3) 0.50 (0.17; 0.84) Likely 93/7/0% 3.25 ± 0.14 3.20 ± 0.11 1.6 (0.5; 2.6) 0.35 (0.11; 0.59) Likely 86/14/0%
COD20L 3.24 ± 0.16 3.18 ± 0.10 1.6 (0.2; 3.0) 0.31 (0.04; 0.59) Likely 76/24/0% 3.25 ± 0.16 3.17 ± 0.12 2.3 (0.9; 3.7) 0.43 (0.17; 0.70) Likely 93/7/0%
COD25R 3.93 ± 0.19 3.87 ± 0.15 1.4 (-0.1; 2.9) 0.28 (-0.01; 0.57) Possibly 68/31/1% 3.92 ± 0.16 3.88 ± 0.14 1.1 (0.2; 2.0) 0.26 (0.04; 0.48) Possibly 68/32/0%
COD25L 3.89 ± 0.18 3.85 ± 0.15 1.1 (-0.5; 2.6) 0.22 (-0.11; 0.54) Possibly 54/44/2% 3.90 ± 0.18 3.83 ± 0.13 1.8 (0.8; 2.7) 0.37 (0.17; 0.57) Likely 92/8/0%
CODpool 9.08 ± 0.37 8.94 ± 0.31 1.5 (0.5; 2.6) 0.36 (0.11; 0.62) Likely 86/14/0% 9.06 ± 0.38 8.89 ± 0.30 1.9 (1.1; 2.8) 0.44 (0.25; 0.64) Very Likely 98/2/0%
0-5 m (s) 1.09 ± 0.06 1.05 ± 0.06 3.2% (1.4; 5.0) 0.63 (0.27; 0.99) Very Likely 97/3/0% 1.06 ± 0.07 1.02 ± 0.07 3.7% (1.2; 6.1) 0.54 (-0.91; -0.18) Likely 94/6/0%
0-10 m (s) 1.82 ± 0.07 1.77 ± 0.07 2.9% (1.6; 4.1) 0.70 (0.39; 1.00) Most Likely 99/1/0% 1.81 ± 0.10 1.76 ± 0.08 2.4% (0.8; 4.1) 0.43 (0.13 ; 0.73) Likely 90/10/0%
0-20 m (s) 3.11 ± 0.11 3.05 ± 0.10 2.0% (1.3; 2.8) 0.57 (0.35; 0.79) Most Likely 100/0/0% 3.1 ± 0.14 3.05 ± 0.11 1.5% (0.5; 2.4) 0.32 (0.11; 0.52) Likely 83/17/0%
0-25 m (s) 3.73 ± 0.12 3.65 ± 0.11 1.9% (1.2; 2.6) 0.55 (0.35; 0.75) Most Likely 100/0/0% 3.73 ± 0.16 3.66 ± 0.14 1.6% (0.9; 2.4) 0.37 (0.19; 0.54) Likely 94/6/0%
LJR (cm) 152.1 ± 13.6 158.8 ± 13.5 4.5% (2.2; 6.8) 0.46 (0.23; 0.69) Very Likely 97/3/0% 149.6 ± 18.1 159.6 ± 16.2 6.9% (3.9; 10.0) 0.51 (0.3; 0.73) Very Likely 99/1/0%
LJL (cm) 151.2 ± 14.3 161.2 ± 13.9 6.7% (3.3; 10.2) 0.63 (0.32; 0.95) Very Likely 99/1/0% 149.9 ± 13.9 163.3 ± 14.4 8.9% (6.3; 11.6) 0.87 (0.62; 1.11) Most Likely 100/0/0%
LJpool (cm) 151.6 ± 12.8 159.9 ± 13.0 5.6% (3.0; 8.1) 0.60 (0.33; 0.86) Very Likely 99/1/0% 149.8 ± 15.3 161.4 ± 14.6 7.9% (5.4; 10.4) 0.70 (0.49; 0.91) Most Likely 100/0/0%
HJR (cm) 172.3 ± 14.2 177.8 ± 16.3 3.1% (0.4; 5.9) 0.36 (0.04; 0.68) Likely 81/19/0% 169.2 ± 15.5 176.3 ± 14.1 4.3% (1.8; 6.9) 0.43 (0.18; 0.68) Likely 94/6/0%
HJL (cm) 173.5 ± 13.6 178.7 ± 15.4 2.9% (0.4; 5.5) 0.35 (0.05; 0.65) Likely 80/20/0% 167.7 ± 15.6 177.8 ± 11.8 6.3% (3.8; 8.8) 0.62 (0.38; 0.86) Most Likely 100/0/0%
HJpool (cm) 172.9 ± 13.1 178.3 ± 15.6 3.0% (0.6; 5.4) 0.37 (0.08; 0.67) Likely 84/16/0% 168.4 ± 15.4 177.1 ± 12.2 5.3% (3.2; 7.5) 0.54 (0.32; 0.75) Very Likely 99/1/0%
CMJR (cm) 18.5 ± 3.1 19.9 ± 2.9 7.8% (3.1; 12.7) 0.41 (0.17; 0.65) Likely 93/7/0% 17.3 ± 3.1 18.2 ± 2.7 5.4% (1.7; 9.3) 0.27 (0.09; 0.46) Possibly 74/26/0%
CMJL (cm) 17.7 ± 3.4 19.5 ± 3.0 10.9% (6.0; 16.1) 0.47 (0.27; 0.68) Very Likely 98/2/0% 16.9 ± 2.3 17.8 ± 1.9 5.7% (2.3; 9.2) 0.39 (0.16; 0.62) Likely 92/8/0%
CMJpool (cm) 18.1 ± 3.1 19.7 ± 2.9 9.3 (5.4; 13.4) 0.45 (0.27; 0.64) Very Likely 99/1/0% 17.1 ± 2.5 18.0 ± 2.1 5.5% (2.6; 8.5) 0.35 (0.17; 0.54) Likely 91/9/0%
CMJ (cm) 37.2 ± 4.6 39.6 ± 4.9 6.6% (4.4; 8.8) 0.48 (0.33; 0.64) Most Likely 100/0/0% 34.1 ± 4.4 36.0 ± 4.1 5.8% (3.3; 8.5) 0.42 (0.24; 0.60) Very Likely 97/3/0%
COD10R: 10 m with right leg with a change of direction of 180°; COD10L: 10 m with left leg with a change of direction of 180°; COD20R: 20 m with right leg with a change of direction of
180°; COD20L: 20 m with left leg with a change of direction of 180°; COD25R: 25 m with right leg with a change of direction of 180°, COD25L: 25 m with left leg with a change of direction of
180°; CODpool: mean of all right (COD10, COD20, COD25) and left COD times; LJR: lateral jump with right leg; LJL: lateral jump with left leg; LJpool: mean of unilateral lateral jumps; HJR:
horizontal jump with right leg; HJL: horizontal jump with left leg; HJpool: mean of unilateral horizontal jumps; CMJR: vertical jump with right leg; CMJJL: vertical jump with left leg; CMJpool:
mean of unilateral vertical jumps; CMJ: bilateral countermovement jump performance; CL: confidence limit. All results are presented in the same direction, that is, a positive change is
considered as an improvement, while a negative change as an impairment.

Eccentric overload training in team sports

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