The Effects of EEG Neurofeedback Training on the Behavioral

Complaints of Soccer Athletes

A Case Study

Erick Conde

, Alberto Filgueiras

, Adriana Lacerda

, Paulo Ribeiro

3,4

and Tiago Arruda Sanchez

Universidade Federal de Pernambuco, Programa de Pós-graduação em Psicologia, Pernambuco, Brazil

Universidade Estadual do Rio de Janeiro, Departamento de Fundamentos em Psicologia, Rio de Janeiro, Brazil

Universidade Veiga de Almeida, Departamento de Psicologia, Rio de Janeiro, Brazil

Consultoria, Estudo e Pesquisa em Psicologia do Esporte (CEPPE), São Paulo, Brazil

Universidade Federal do Rio de Janeiro, Faculdade de Medicina, Rio de Janeiro, Brazil

Keyword: Neurofeedback, Sport Psychology, Soccer, Behavior, Sensorimotor Rythm.

Abstract: Several studies supports that neurofeedback training enhances human skills to control the predominance of

cerebral activity by specific frequencies. This training modality was related to efficient applications in

clinical use, education, businesses and sports. Behavioral changes were found after the neurofeedback

training in various circumstances, eliciting more functionality and accuracy, but no studies were found

considering the effects of the neurofeedback at the behavioral and psychological complaints of young soccer

athletes. The aim of this work was to evaluate the effects of a sensorimotor rhythm training program and its

applicability for the sport psychology practice. Five soccer athletes referred to the Sport Psychology

department were systematically trained to increase the sensorimotor rhythm amplitude and then, were

interdisciplinary monitored by coaches, physical trainers, medical and psychological services. As results, 4

from 5 athletes were considered remitted from the initial dysfunctional complaints. These changes were

found such in technical, tactical, physical and psychological aspects, and they varied between athletes and

personal demands. As conclusions, the present work pointed evidences that the neurofeedback training

program can be an important technology to support the practices of the sport psychology, as to enhance

functional behaviors and to promote mental health for developing soccer athletes.

1 INTRODUCTION

The neurofeedback is a training technique based on

the feedback of the physiological signal to the brain,

which enables people to alter and control their brain

waves and exercise the own self-regulatory

mechanisms (Larsen and Sherlin, 2013). Acting as a

kind of operant conditioning, the neurofeedback

applications emerged in health promotion, education

and in centers of human performance, as the sports

clubs (Sterman, 2000).

The neurofeedback has been traditionally made

by the electroencephalographic (EEG) or

hemoencephalographic (HEG) signals (Hammond,

2011), although some researchers has proved that

the functional magnetic resonance imaging (fMRI)

can also used as an efficient neurofeedback modality

(Weiskopf et al., 2004). Focusing on the EEG

Neurofeedback, also named EEG Biofeedback, it

has been already proved as a safe and efficient

method for training the brain to regulate mental

states and related behaviors, with utilities in peak

performance and in clinical demands (Larsen and

Sherlin, 2013). There is a broad range of beneficial

effects of EEG neurofeedback training on athlete’s

performance proved in several studies and different

modalities (Hammond, 2007; Dupee and Werthner,

2011; Wilson and Peper, 2011; Perry et al., 2011;

Wilson, Peper and Moss, 2006; Nan et al., 2014).

Regarding soccer modality, Wilson and

colleagues (2006) reported a case study with the

Italian players during the 2006 World cup. They use

a space referred as the “Mind Room”, which

biofeedback modalities comprised the feedback of

such brainwaves (neurofeedback), cardiovascular

and electrodermal responses, while the soccer

players viewed short video clips of successful and

unsuccessful performances. The main purpose of

132

Conde, E., Filgueiras, A., Lacerda, A., Ribeiro, P. and Sanchez, T..

The Effects of EEG Neurofeedback Training on the Behavioral Complaints of Soccer Athletes - A Case Study.

In Proceedings of the 3rd International Congress on Sport Sciences Research and Technology Support (icSPORTS 2015), pages 132-138

ISBN: 978-989-758-159-5

this study was training psychological skills to help

them to relax and control physiological reactions

under pressure situations. The success of the "Mind

Room" program may have reflected in the Italian

world title.

Unfortunately, although the EEG biofeedback

has gained prominence in the international sports

centers, it has little attention in Brazilian sport

science over the last decades. The emotional

dysfunction of Brazilian soccer players during 2014

World Cup and also 2015 American Cup may reflect

the negligence or a old-fashioned and poorly

psychological assistance. The fact is that

Zaichkowsky (2012) pointed some limits to

introduce this kind of assistance, as the fact that the

hardware and technology were expensive, and that

the sport practitioners and managers do not know the

theory and application of this technology. Although

the Brazilian difficulties, this case study reports a

positive experience with young Brazilians soccer

players, referred to the Sport Psychology

department.

Among diverse EEG Neurofeedback training

protocols, the Sensorimotor Rhythm (SMR) can be

done enhancing of 12–15 Hz band while inhibiting

outer lying bands in the EEG spectrum (Vernon et

al., 2003). The SMR training has been related to

several cognitive gains (Vernon et al., 2003; Nabavi

et al., 2014; Doppelmayr and Weber, 2011). These

beneficial effects were found in several studies,

showing improvements on reaction times (Nabavi et

al., 2014), affective processes (Gruzelier, 2014a),

visuospatial abilities and creativity (Doppelmayr and

Weber, 2011). Also, SMR learning indices are

positively associated with the reduction in

commission errors in sustained attention tasks

(Egner and Gruzelier, 2001) and with memory

consolidation (Schabus et al., 2014). In Sports, this

training protocol was also proved as an effective

method (Del Percio et al., 2009; Brown et al., 2012;

Perry, Shaw and Zaichkowsky, 2011).

Looking to these SMR related effects on mood,

behavior and cognition, the present study analyze

the effects of SMR training on the complaints of 5

soccer athletes and its applicability in soccer

demands. The aim of this work is to evaluate

behavioral changes after a sensorimotor rhythm

training program (enhancing 12-15 Hz) and its

applicability in soccer demands.

2 METHODS

The research can be considered as a case study, with

exploratory and descriptive methods. This

methodology approach comprehends analysis under

the epistemological view of subjectivism

interpretative and phenomenological and was not

designed to consider potential placebo effects,

neither to promote widespread conclusions (García-

Celay and León, 2007; Yin, 2013). However, the

case study methods are quite relevant for

development the sport and health sciences, enabling

the sharing of personal experiences and contributing

for the dissemination of knowledge, debates and

reviews of strategies, diagnoses, interventions and

learning. In psychology, this method can be

considered relevant and a very useful investigative

tool (Hardy et al., 2001; García-Celay and León,

2007; Yin, 2013).

2.1 Participants

The study involved 5 young soccer athletes (15-19

years old), affiliated in a traditional and professional

soccer club at Rio de Janeiro, Brazil. All of them

were referred to the Sport Psychology Department

with behavioral and psychological complaints. To

ensure their privacy, participants will be referenced

with representative numbers. The respective tactical

functions were: athlete 1, center defender; athlete 2,

midfield; athlete 3, a center forward; athlete 4,

goalkeeper; athlete 5, midfield. Involved either five

institutional sectors linked to the soccer department:

physical therapy (2 professionals), psychology (3

professionals), physical education (3 professionals)

and the coach areas (2 professionals).

2.2 Apparatus and Procedure

The EEG biofeedback training of the sensorimotor

rhythm was conducted according Vernon and

colleagues (2003) periodicity: over a period of 4

weeks, with each participant receiving two training

sessions per-week. Each session contained four 5-

min periods. The training program was administered

using the ProComp system (Thought Technology

Ltd) and the Biograph Plus 2.1 software. Signal was

acquired at 160 Hz, converted and band filtered to

extract delta (0–4 Hz), theta (4–8 Hz), alpha (8–12

Hz), SMR (12–15 Hz) and beta (18–22 Hz)

components. The active electrode was recorded from

CZ for all training session, with reference placed on

the left and ground electrode on the right earlobes

respectively. Impedance levels were monitored by

visual inspection and the artifact rejection thresholds

were set individually, suspending feedback when

eye-movements or other muscle activity caused

The Effects of EEG Neurofeedback Training on the Behavioral Complaints of Soccer Athletes - A Case Study

133

Figure 1: Operating dynamics of the neurofeedback sessions: signals were collected from Cz, amplified and a real-time

feedback was displayed on the computer.

gross EEG fluctuations.

The SMR (12–15 Hz) were fed back using an

audio–visual online feedback loop in the form of a

bar, with the amplitude of the SMR frequency

varying in the size of the bar. The participants’ task

was to increase the size of the training frequency bar

and, on meeting this goal, a clown performed

juggling with music (figure 1). For training, the

athletes remained seated and with his hands resting

on his legs, they were instructed to suppress any

thought and to focusing in the game.

2.3 Analysis

Analysis were made considering the reports of the

five institutional sectors. The single variable

investigated was the multidisciplinary concordance

about the initial dysfunctions, considering the

incidence of behavioral complaints such as physical

symptoms, technical questions and tactical

execution. The analysis also considered the methods

and techniques used by each sector because they are

content of the institutional reports. Psychological

assessments were made using a combination of

techniques, which comprised behavioral

observations (during trainings and matches),

individual interviews and multidisciplinary

meetings. The Interviews investigated recent life

experiences at psychosocial, emotional, cognitive

and behavioral spheres. The physical assessment

was made through clinical interviews made by

doctors and physical therapists asking about physical

state, injuries and complaints related to the athletes.

The technical and tactical assessments were made

through extensive and systematic daily training

observations for the coach and physical trainers. The

training sessions observed varied according the day

of the week, and may comprise soccer game

trainings, technical or physical sessions. In addition,

some external events were also considered as non-

institutional indicators of behavioral changes and

were described in results.

The criteria for concluding if the initial

complaints changed or not, required unanimous

concordance about the absence of dysfunctional

states. The analysis considered reports made before,

and after 4 months to the end of the 4-week

neurofeedback training period.

3 RESULTS

All participants were continuously monitored by the

multidisciplinary sectors. During the neurofeedback

sessions, all of the athletes demonstrated enhancing

skills to generate, maintain and to manage the

desired SMR wave pattern.

The results of multidisciplinary evaluation are

below specified for each athlete and summarized in

table 1. The analysis of this case study showed that

remission of the initial complaints was attributed to

80% of the sample (4 from 5 athletes).

3.1 Athlete 1

When he started the neurofeedback practices, he was

training away for the remaining athletes. The

coaching staff and the soccer coordination did not

believe in his capacity to stay in the team, because

serious technical and tactical errors was observed,

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Table 1: Results of initial multidisciplinary assessment, considering psychological, physical, technical and tactical aspects.

Athletes Psychological aspects Physical aspects Technical and tactical aspects

Athlete 1

Emotional instability; sadness; anxiety;

anger; nonconformity thoughts;

impairments; unfocused; slow In taking

decisions.

Low technical level; difficulties in tactical

execution;

alternate Condition;

doing separate trainings;

expectation to be sent out off the team

Athlete 2 High anxiety, recurrent insomnia

Recurrent injuries; slow

physical recovery

Titular condition; regular performance

Athlete 3

Impulsiveness; recurrent anger; inadequate

relationships with technical committee;

indiscipline episodes

Alternate condition; difficulties In Tactical

Execution

Athlete 4

Inadequate interpersonal relationships;

psychological resistance; recurrent delays,

indiscipline, recurrent anger episodes

Performance Instability

Athlete 5 Anxiety, impulsivity and restlessness Motor restlessness

Diverse Fouls And Misconduct; Constant

Punishments With Yellow And Red Cards.

detected during the interdisciplinary observation

during soccer trainings and official matches. When

asked about his performance, the athlete reported

perceptions of uncertainty and oscillations. It was

also observed that the temporal judgment was

affected, because sometimes his timing accuracy

failed, anticipating movements or slowing

reactions. He was characterized as a player with

low technical level and with difficult performing of

tactical instructions when requested by the team

coach. After two weeks (four training sessions with

neurofeedback), he was integrated into the group

again, and selected to participate in Switzerland on

a sub-20 international competition supported by

the Fédération Internationale de Football

Association (FIFA). After more two weeks, during

the period when the team remained outside of the

country, the ATHLETE 1 demonstrated technical

improvements from the point of view of the team's

coach. As an external indicator, the full recovery of

the initial performance complaints were proven by

a prize awarded at the FIFA competition, being

considered one of the best players of the event.

3.2 Athlete 2

He self-reported the remission of insomnia crises

and less anxiety levels. The physiotherapy section

detected less physical complaints. The psychology

sector identified that the trainer praised his

performance more times. As external indicators, he

was considered his convocation to Brazilian sub-20

soccer selection, two months after the end of the

Neurofeedback program.

3.3 Athlete 3

Before the neurofeedback practices, the athlete 3

was dissatisfied with the coach and with the

reserve situation. For the Psychology sector, the

athlete' dissatisfaction influenced his behavior

during several soccer training sessions, giving

inappropriate tactical conducts and influencing the

quality of your relationship with some members of

the coaching staff and with the institution itself. He

was referred to the Psychology sector by the coach

after demonstrate persistent indiscipline in relation

to the coaching staff and other employees of the

institution. His rebel behavior was behaviorally

manifested on the pitch in the refusal to obey

simple tactical instructions requested by the coach.

Initial behavioral changes were found after few

weeks of completing the neurofeedback program.

As change indicators, the absolute starter can be

considered and also the more flexible relations

with coaches’ instructions and the enhancement of

converted goals. During the follow-up period were

not recorded indiscipline complaints nor

relationship problems. Two external indicators of

changes in the initial complaints must be

considered: the artillery of the principal soccer

tournament to the category and also, the

convocation for Brazilian Sub-17 soccer selection

by the Brazilian Football Confederation.

3.4 Athlete 4

Although being in technical progress, even before

beginning the neurofeedback training, the coaching

staff increasingly praises to this goalkeeper. The

only changes recorded after the start of activities

with neurofeedback was the improvement in the

relationship with the psychology service (after a

history of resistence) and also with the goalkeeping

coach. Were also identified delays reductions for

the training sessions, which were common before

the Neurofeedback program.

The Effects of EEG Neurofeedback Training on the Behavioral Complaints of Soccer Athletes - A Case Study

135

Table 2: Results of the multidisciplinary assessment after the SMR Neurofeedback training and the respective qualitative

condition of the initial complaints.

Athlete Overall post SMR assessment Qualitative condition of the initial complaints

Athlete 1

Satisfactory performance; emotional stability; greater

accuracy and decision making; more ability to

focusing; titular condition; won a prize at a

international competition sponsored by FIFA

Remission of the initial complaints. The

athlete's overall condition was qualitatively

different after the neurofeedback program

Athlete 2

Insomnia remission; lower levels of anxiety; injuries

decreases; more coach's praises; convocation for

Brazilian Sub-17 team

Remission of the initial complaints. The

athlete's overall condition was qualitatively

different after the neurofeedback program

Athlete 3

Higher emotional control; more functional behaviors;

titular condition; Artillery in the state championship;

convocation for Brazilian Sub-17 team; none

indiscipline episode was reported

Remission of the initial complaints. The

athlete's overall condition was qualitatively

different after the neurofeedback program

Athlete 4

Good relationship with the team work; lower

psychological resistance; reducing delays; none

indiscipline episode was reported

Remission of the initial complaints. The

athlete's overall condition was qualitatively

different after the neurofeedback program

Athlete 5

Anxiety; restlessness; impatience; no red cards were

attributed but still received some yellow cards

No changes were found for the initial

complaints. The athlete's overall condition was

not qualitatively different

3.5 Athlete 5

For the athlete 5, the main complaint was the

excessive number of expulsions and of yellow cards

obtained during championship. Analyzing the

reasons for the dangerous faults, it was identified

that the athlete not expected the best time to steal the

ball from the opponent, he was impulsive and

anticipated his movement with unnecessary faulty

entries. In addition, during psychological sessions,

psychomotor agitation were found and others

evidences about anxiety. After the neurofeedback

program, the staff doesn’t found significant

behavioral changes, he continued to make

unnecessary fouls and earned many yellow cards,

even without being outcasted after neurofeedback

program ended.

On a general view, the initial complaints varied

between athletes, but we can summarize the

presented questions as dysfunctional behaviors,

emotional instability and with some performance

problems (technical and/or tactical aspects).

The results for each athlete, pre and post

neurofeedback training program were below

summarized and discriminated in table 2. In

common, the athletes enhanced cognitive skills,

emotional control and the soccer performance (in

tactical and/or technical aspects), excepting the

athlete 5.

4 DISCUSSION

The purpose of this paper was to disclose the

neuroscientific contributions for high performance

sports and also during the athlete development. The

neurofeedback training can be an important tool to

assist the other professional fields in a

multidisciplinary way. Herein, ours results showed

how this technology led to important qualitative

changes in 4 from 5 soccer athletes referred to the

Sport Psychology department.

Several indicators of the neurofeedback

efficiency in high performance athletes were guided

on quantitative analyzes which considered the

subject's ability to maintain and generate the specific

trained brain wave allied to behavioral measures in

specific cognitive tests (Hammond, 2007; Dupee and

Werthner, 2011; Wilson and Peper, 2011). However,

critical issues considered that such scalp changes

and quantitative cognitive perspectives might not

reflect substantial changes in one's life (Vernon,

2005). According Maanen (1979), to verify the

quality of a phenomenon is not necessary to consider

implicit and accurate data related to such

manifestation. In this way, the combination of

systematic multidisciplinary assessments attested

important changes for these athletes' professional

and personal spheres, proving the relevance of the

neurefoeedback technological support.

Although Vernon and colleagues (2003) reported

advances after 8 training sessions with SMR

protocol, the behavioral changes in some of the

athletes of this study, surprised coaches, researchers

and the sport psychology team. According to Wilson

and Peper (2011), the neurofeedback training with

high level athletes have important differences when

compared to the clinical use. One of them is the

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athlete's learning ability: they would be able to

conduct a more intensive transfer of learned skills to

a real demand, which would be responsible to faster

results when compared to clinical patients.

Our results were found in different spheres, with

technical, tactical and psychological benefits

reported. These results may be explained by the

literature that proves a diverse range of SMR

neurofeedback efficiency. The SMR neurofeedback

training was already be related to beneficial effects

in different cognitive functions (Vernon et al., 2003;

Nabavi et al., 2014; Doppelmayr and Weber, 2011),

emotion (Gruzelier, 2014a), accuracy (Egner and

Gruzelier, 2001) and performance (Gruzelier, 2014b;

Del Percio et al., 2009; Brown et al., 2012; Perry et

al., 2011).

5 CONCLUSIONS

Using systematic and qualitative methods to analyze

behavioral changes, the work clearly identified that

behavioral patterns were changed after the SMR

neurofeedback training, when compared to the initial

complaints. As an applied study, this work helped to

recover athletes who would be wasted or underused.

Therefore, the data also reinforce that the

neurofeedback is an important technology to support

the soccer players formation, ensuring better results

for the institution's main role. As conclusions, we

suggest that the control of SMR frequency can be an

interesting psychological training strategy for soccer

athletes' development, being related to mental health

and functional behavioral skills.

ACKNOWLEDGEMENTS

We thanks the Clube de Regatas do Flamengo

(CRF) for the support and permission to realize the

applied study with the soccer players; also, we

would like to thanks Bianca Kalil, Rogério

Lourenço, Diogo Linhares, Rivelino Serpa Espinosa

and the CRF's medical department, for all the

assistance; finally, to the athletes due to their

confidence and involvement with the proposed

activities.

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