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: 1Faculty of Health Sciences, University of San Jorge, Zaragoza, Spain. 2Department of Strength and Conditioning. Chelsea FC, Cobham, England. 3Sports

Performance Lab. INEFC Barcelona, Spain. 4ASPIRE 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

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.

1Faculty of Health Sciences, University of San Jorge, Zaragoza, Spain.

2Department of Strength and Conditioning. Chelsea FC, Cobham, England.

3Sports Performance Lab. INEFC Barcelona, Spain.

4ASPIRE 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: [email protected]

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

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mailto:[email protected]





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

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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

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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

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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.

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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

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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

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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–

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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.

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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

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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

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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

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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

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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.

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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

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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.

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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).

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“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.

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