Consequences From Emotional Stimulus on

Breathing for Singing

*Viggo Pettersen and †,‡Kare Bjørkøy *Stavanger, Norway, y�Arhus, Denmark, and zTrondheim, Norway

Summary: This study aimed to investigate the effect from emotional stimulus on the correlation between intercostal

AccepFrom

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(INT)/abdominal (rectus abdominis [RC], lateral abdomen [OBL], and lower lateral abdomen [LOBL]) muscle activityand trunk wall (upper thorax [UTX], lower thorax [LTX], and abdomen [ABD]) movement. An electromyographic(EMG) activity was recorded from the INT, RC, OBL, and LOBL sites. UTX, LTX, and ABD movement were tracedwith three strain gauge sensors. Recordings were compared between singing with emotional stimulus (ES) and withoutemotional stimulus (NES). Muscle activity was recorded by use of an ambulatory four-channel monitoring system(Physiometer PHY 400, Premed, Norway). Seven advanced student singers (three males and four females) participatedas subjects. Four sample performances were performed: (1) extreme tones, (2) swell tones, (3) arpeggio, and (4) glis-sando. All sample performances were sung on the vowel /a:/. We conclude that classical singers change their breathingpattern when they vocalize using ES compared with using NES. The results imply that vocalizing using ES facilitatesa more prominent role for LOBL activity in the positioning of the abdominal wall and thorax than observed when vo-calizing using NES.Key Words: Emotional stimulus–Breathing–Electromyography–Muscles–Abdomen–Thorax–Classical singing.

INTRODUCTION

Singing is a physical and an artistic act. Some singing teachersare aware of this truth and use scientific facts, additionally toyears of experience from singing and teaching singing, in a ho-listic approach to teach classical singing.1 Nevertheless, in thesinging pedagogy, a prominent feature is still the different atti-tudes used to approach the teaching of singing technique. Twoextremities of approaches are, on the one verge, the technicallyintense pedagogue who may not understand why so little suc-cess attends a public performance of a pupil who has masteredthe technical precepts of the studio so well. On the other verge,some singers are taught to solve their technical problems by fo-cusing on vocal colors and expressive singing, convinced thatthere are no technical matters that cannot be solved through in-volvement in text and music.2 These two diametrical opposedviews, on how to approach the long-lasting process of acquiringan enhanced singing technique, would probably imply disparityin use of the breathing apparatus.

In the history of the teaching of classical singing, a majorityof the singing teachers have been using vocalization of exer-cises as a method for improving ‘‘technical skills.’’3 Even ifteachers are using the same exercises the benefit on the studentmay vary. One reason for this may be that some singing teachersadvocate the importance of vocalization arising from emotionalstimulus,1 stating that the emotional content of the utteranceand the way the voice organs are used presumably are con-nected.4 Others are not equally preoccupied with emotionswhen instructing vocalization of exercises.2

ted for publication August 20, 2007.the *Department of Music and Dance, University of Stavanger, Stavanger, Nor-yal Academy of Music, �Arhus, Denmark; and the zNorwegian University of Sci-Technology, Trondheim, Norway.

ss correspondence and reprint requests to Prof. Viggo Pettersen, Department ofnd Dance, University of Stavanger, Bjergsted, N-4036 Stavanger, Norway.iggo.pettersen@uis.nol of Voice, Vol. 23, No. 3, pp. 295-303997/$36.00

9 The Voice Foundation.1016/j.jvoice.2007.08.006

A study by Foulds-Elliot et al5 examined whether it was pos-sible to distinguish between professional opera singers’ breath-ing patterns during (1) technical singing and (2) singing withemotions. It was observed that emotional connected singing(compared to technical singing) used more air with a greaterpercentage of vital capacity, and it was suggested that the per-forming state of mind itself might influence the technicalapproach to operatic singing. Future research to distinguish be-tween physiological components of singing was recommended.As far as known, few studies on the effect from emotional stim-ulus on muscle activity, when breathing for classical singing,have been performed. This study aims to investigate intercostal(INT)/abdominal (rectus abdominis [RC], lateral abdomen[OBL], and lower lateral abdomen [LOBL]) muscle activityand trunk wall (upper thorax [UTX], lower thorax [LTX], andabdomen [ABD]) movement in vocalization of exercises: (1)using emotional stimulus (ES) and (2) singing the same exer-cises in a neutral, noninstructed version (NES). In the studyby Foulds-Elliot et al,5 singing with emotions was associatedwith a greater amount of air. Other studies have shown that mus-cle activity is needed to regulate subglottal pressure (andthereby trunk movement) for the intended phonation task.6–9

Muscle activity also varies involuntarily with the challenge ofthe phonation task.8 In addition, it is expected that muscle activ-ity will increase as the circumference of the trunk diminishes.10

The hypothesis is, therefore, that muscle activity is negativelycorrelated to trunk movement and that these correlations willdiffer between singing with NES and ES.

Because body and voice take many years to develop fully,1,3

classical singing students are frequently targeted of a teacher’sdetailed instruction on posture and breathing. Therefore, ad-vanced classical singing students are selected as subjects.

To summarize, on advanced classical singing students, thisstudy will, firstly, investigate the effect from ES on the correlationbetween INT/abdominal muscle activity and trunk wall move-ment. Correlation coefficients will be compared between sampleperformances (NES vs ES). Secondly, electromyographic(EMG) loading between NES and ES will be investigated.

TABLE 1.

The Voice Type, Age, Height, Weight, and Body Mass

Index of All Subjects

Voice Type Age (y) Height Weight (kg)

Body Mass

Index

1 Baritone 30 192 78 21.2

2 Tenor 1 32 173 71 23.7

3 Tenor 2 28 180 69 21.3

4 Mezzo 34 164 79 29.4

5 Contra alto 26 180 65 20.1

6 Soprano 1 28 174 56 18.5

7 Soprano 2 26 170 86 29.8

RC

UTX

LTX

ABD

INT

LOBL

OBL

FIGURE 1. The anatomical position of electrode placement on the

intercostal (INT), rectus abdominis (RC), abdominal (OBL), and lower

abdominal (LOBL) muscles, and the position of respiration sensors on

thorax (UTX and LTX) and abdomen (ABD) are shown.

Journal of Voice, Vol. 23, No. 3, 2009296

MATERIAL AND METHODS

Subjects

Seven advanced conservatory classical student singers (four fe-males and three males), age ranging from 26 to 34 years, partic-ipated in the study (Table 1). All singers attended a classicalsinging study at the Academy of Music, �Arhus, Denmark.Informed consent was given by the participants before the startof the experiment.

Recordings

Muscle activity was recorded from INT, OBL, RC, and LOBLby use of an ambulatory four-channel monitoring system (Phys-iometer PHY 400, Premed, Norway). Silver/silver chloridebipolar electrodes with an active diameter of 6 mm and a cen-ter-to-center distance of 20 mm were used to record the surfaceEMG signal. The EMG signals were band-pass filtered at 20–800 Hz and sampled at 1600 Hz. They were thereafter A/D con-verted and the root-mean-square (RMS) value calculated. MeanRMS values, determined for consecutive 100 ms intervals, weretransmitted at 10 Hz on a serial interface to a PC Laptop. Theprocessed signals were further analyzed by use of the Physio-meter software (Premed, Oslo, Norway). For INT, the caudalelectrode was placed between costae 9 and 10, perpendiculardown from papilla mammaria, and the rostral electrode betweencostae 8 and 9 on the same line. For RC, the caudal electrode waspositioned 3 cm to the right of the midline at the height of um-bilicus and the rostral electrode 2 cm higher at the same distancefrom the midline. For OBL, the rostral electrode was placed2 cm below the lowest part of the rib and the lower electrode2 cm further down toward the Os pubis. For LOBL, both elec-trodes were placed perpendicular to the electrodes of the OBLsite, with the caudal electrode 1 cm above the Spina iliaca ante-rior inferior. Figure 1 shows the electrode positions, whichcorrespond to locations with stable, high EMG responses. Theground electrode was placed on Crista iliaca. The EMG re-sponses were calibrated in percentage of the EMG response inmaximal voluntary contraction (%EMGmax). For INT, OBL,and LOBL, the attempt to maximal compress the abdomengave the best response. The maximal contraction movementfor RC had the subjects half lying in a chair with immobilizedfeet, lifting the upper part of the body halfway to sitting posture.Two or three attempts of a maximal contraction were made foreach muscle. Trunk movement was traced by three strain gaugesensors, placed around the thoracic (UTX and LTX) and abdom-inal (ABD) wall, sensing trunk circumference. The UTX sensorwas located with the upper edge at the axilla level, the LTX sen-sor around the lowest part of TX, and the ABD sensor was placedaround abdomen at the height of umbilicus. The sensors weretested and found to show a linear relationship between trans-ducer output and chest circumference within the movementrange defined by maximum expansion and maximum contrac-tion of TX and ABD in regular singing. Electrode and straingauge placements are shown in Figure 1.

Procedure

The recordings were performed in a relatively large studio(50 m2, with 3 m high ceiling), where all subjects customary

received singing lessons. To be able to control the procedurein retrospect, all recordings were video taped with a SonyDual Media digital video camera (DCR-PC 100E; SonyCorp., Japan). Four sample performances were performed: (1)extreme tones, (2) swell tones, (3) arpeggio, and (4) glissando.

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Viggo Pettersen and Kare Bjørkøy Emotional Stimulus on Breathing for Singing 297

All sample performances were sung on the vowel /a:/, and in-structed shortly before the recording concerning pitch, vowel,vocal loudness, and duration. The extreme tones consisted ofthree tones. The first was the comfort tone (used to test if thevoice was functioning well, chosen freely by the singer), thesecond was the individual singer’s highest tone accessiblewhen performing, and the third tone was the lowest tone avail-able likewise. To establish a customary sound production, themiddle tone was first performed, then the highest version, andfinally the lowest version. The swell tones were performed atthe same pitches as the extreme tones. Each tone started in p,with a crescendo into mf, and a decrescendo back to p. The ar-peggio was performed in ascending and descending triads con-stituting an octave (D4–D5). The glissando was performed withcontinuous changes of pitch, staring at D4, entering high pitch,and down to low pitch. Highest pitch and lowest pitch were de-termined in accordance with each singer’s voice type and range.Each sample performance was first performed in the NES modeand then in the ES mode (NES, eight and ES, eight). A total of16 separate recordings were made, thereby reducing the risk ofdeviant results due to random variation between sample perfor-mances. The length of each sample performance was limited toone breathing sequence. The chance of a fatigue effect would,therefore, be small. Each recording started shortly before inha-lation and was terminated shortly after the end of phonation.The instruction of procedure was communicated to the singerswhile the electrodes and the respiration sensors were mounted.The entire recording session lasted approximately 45 minutesfor each subject, including the mounting of electrodes and res-piration sensors, calibration maneuvers, and recordings.

FIGURE 2. Group result of correlation tests singing with NES and

ES. Each symbol presents the mean (Spearman r) of seven singers’

means of all correlations coefficients: mean r of 57 r (7 [singers] 3 8

[sample performances]).

Analysis

The data were statistically tested by use of SPSS 13 for Win-dows (SPSS Inc., Chicago, IL). The RMS-detected EMG activ-ity and chest transducer responses, both quantified at a timeresolution of 0.1 s, were used to calculate the Spearman’srho (r) correlation coefficient when testing for associationsbetween channels. The Wilcoxon nonparametric two-relatedsamples test was used to compare the calculated correlationcoefficients for EMG versus strain gauge channels betweenthe NES and ES recordings. The same test was used to com-pare median EMG responses between the NES and ES record-ings.

RESULTS

The findings of this study are illustrated in Figure 2, showingscatter plots of group means of correlation coefficients forEMG (INT, OBL, LOBL, and RC) versus strain gauge (UTX,LTX, and ABD) channels. Figures 3–5 show individual timeplots of EMG responses and trunk movement (UTX, LTX,and ABD) representative for breathing behaviors observed inthe two modes of singing (NES and ES). Table 2 shows the re-sults from statistical analyses of the correlation coefficients cal-culated for EMG versus strain gauge channels, and Table 3shows the group result of statistical analyses of EMG loadingbetween settings (NES and ES).

The main finding in this investigation is that the group resultshows negative correlations between the strain gauge channelsand OBL/LOBL EMG channels, and that these correlations de-crease from singing with NES to singing with ES. For all corre-lations illustrated in Figure 2A (strain gauge vs INT, OBL, andLOBL), the result of statistical tests (Wilcoxon r) showed sig-nificance for lower correlation coefficients when using ES com-pared with using NES (r¼ 0.038). This modification of thebreathing behavior was most pronounced observed in correla-tion coefficients calculated for LTX versus LOBL and ABDversus LOBL channels (Figure 2A). Corresponding analysesof positive correlations between channels (strain gauge vs RC,Figure 2B) showed no significant difference between the NESand ES settings. Nevertheless, it is worthwhile noticing that cor-relation coefficients for ABD versus RC channels increasedfrom singing with NES to singing with ES (Figure 2B), mostpronounced observed for the calculated correlation coefficientsfor the middle and highest of the extreme tones, arpeggio, andglissando. The statistical analyses of correlations between chan-nels were performed on the mean correlation coefficient of eightperformances in each of the two modes of vocalization (eightNES and eight ES): mean r¼mean of seven singers’ mean

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FIGURE 3. Individual time plots of INT, RC, OBL, and LOBL sites’ EMG activity and UTX, LTX, and ABD movement (female singer [Table 1:

6] singing the glissando).

Journal of Voice, Vol. 23, No. 3, 2009298

correlation coefficient of eight correlations; three sustained andthree swell tones, arpeggio, and glissando¼mean of 56 r). Eventhough the group result showed correlations between straingauge and EMG channels (except RC) to be lower when singingwith NES, within-singers activity patterns would vary between

sample performances. Visual inspection of EMG activity andtrunk movement, singing with NES and ES, grouped the sevensingers in three activity patterns.

Major pattern changes between the NES and ES modes of vo-calization were observed in three singers in this investigation

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FIGURE 4. Individual time plots of INT, RC, OBL, and LOBL sites’ EMG activity and UTX, LTX, and ABD movement (female singer [Table 1:

7] singing the glissando).

Viggo Pettersen and Kare Bjørkøy Emotional Stimulus on Breathing for Singing 299

(Table 1: singers 1, 5, and 6 [shown in Figure 3]). For the singerillustrated in Figure 3, correlation coefficients (r) for INT andLOBL versus strain gauge channels (except INT vs ABD)changed from positive (NES) to negative when singing withES: INT versus UTX; r¼ 0.02/�0.21, INT versus LTX;r¼ 0.46/�0.32, and INT versus ABD; r¼�0.12/�0.32, re-spectively. LOBL versus UTX; r¼ 0.07/�0.38, LOBL versus

LTX; r¼ 0.36/�0.51, and LOBL versus ABD; r¼ 0.21/�0.54, respectively. Correspondently, correlations were ob-served for OBL versus LTX; r¼�0.59/0.25. Increased posi-tive correlations were observed for OBL versus UTX;r¼ 0.2/0.24, OBL versus ABD; r¼ 0.1/0.26, RC versusABD; r¼ 0.3/0.9, and RC versus LTX; r¼ 0.79/0.9, respec-tively. The time plots of the singer illustrated in Figure 2

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NES ES

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FIGURE 5. Individual time plots of INT, RC, OBL, and LOBL sites’ EMG activity and UTX, LTX, and ABD movement (male singer [Table 1: 3]

singing the glissando).

Journal of Voice, Vol. 23, No. 3, 2009300

show the most pronounced pattern change observed among thethree singers with major pattern changes.

Minor pattern changes were observed in two female singers,illustrated in Figure 4. These two singers had the highest bodymass index among all singers in this investigation (Table 1:

singers 4 and 7 [shown in Figure 4]). Corresponding correlationcoefficients to the singer illustrated in Figure 3 are INT versusUTX; r¼ 0.08/�0.21, INT versus LTX; r¼ 0.03/�0.08, andINT versus ABD; r¼ 0.03/�0.25, respectively. LOBL versusUTX; r¼�0.63/�0.39, LOBL versus LTX; r¼�0.65/�0.55,

TABLE 2.

Results of Wilcoxon Two-Related Samples Test (Two-Tailed), Used to Test the Group Results of Correlation Tests

(Spearman r) Between the NES and ES Settings

Sample Performance (Task) NES

Setting vs ES Setting Correlations

NES, Mean

and Range (r)

ES, Mean

and Range (r) Test Statistics (Z) Sig. (Two-Tailed)

EMG (INT, RC, OBL, LOBL) to strain gauge (UTX, LTX, ABD) channels

Middle extreme tone �0.2 (0.2/�0.41) �0.1 (0.35/�0.34) �2.903 0.004*

Highest extreme tone �0.33 (0.28/�0.67) �0.39 (0/�0.59) 1.020 0.308

Lowest extreme tone �0.1 (0.18/�0.37) �0.14 (0.21/�0.44) 1.845 0.065

Middle swell tone �0.1 (0.13/�0.31) �0.15 (0.11/�0.43) 1.726 0.084

Highest swell tone �0.17 (0.18/�0.46) �0.2 (0/�0.4) 1.334 0.182

Lowest swell tone �0.05 (0.37/�0.35) �0.06 (0.23/�0.39) 0.353 0.724

Arpeggio �0.19 (0.07/�0.41) �0.07 (0.2/�0.22) �2.667 0.008*

Glissando �0.12 (0.11/�0.3) �0.11 (0.13/�0.39) �0.314 0.754

Significance at alpha level 5% is marked with an asterisk.

Viggo Pettersen and Kare Bjørkøy Emotional Stimulus on Breathing for Singing 301

LOBL versus ABD; r¼�0.01/�0.30, OBL versus LTX;r¼�0.25/�0.42, OBL versus UTX; r¼�0.09/�0.51, OBLversus ABD; r¼�0.56/�0.5, RC versus ABD; �0.51/�0.78,and RC versus LTX; r¼ 0.32/�0.04, respectively.

Negligible pattern changes were observed in two male singers(Table 1: singers 2 and 3 [shown in Figure 5]). Correspondingcorrelation coefficients to the singers illustrated in Figures 3and 4 are INT versus UTX; r¼�0.33/�0.06, INT versusLTX; r¼�0.39/�0.19, and INT versus ABD; r¼�0.59/�0.18, respectively. LOBL versus UTX; r¼�0.29/�0.16,LOBL versus LTX; r¼�0.29/�0.13, LOBL versus ABD;r¼�0.51/�0.31, OBL versus LTX; r¼ 0.08/0.31, OBL versusUTX; r¼ 0.12/0.13, OBL versus ABD; r¼�0.2/�0.18, RCversus ABD; �0.49/�0.3, and RC versus LTX; r¼�0.27/�0.33, respectively.

Table 3 shows that the modification of EMG loading, fromsinging with NES to singing with ES, is minor. Even thoughthe group result for EMG loading did not considerably vary be-tween singing with NES and singing with ES, variations wereobserved on the samples performance level. In the ES versionof the highest of the extreme tones, OBL EMG loading was sig-nificantly proved to be higher than observed when singing in theNES version (P¼ 0.043). On the individual level, some resultsshow a combination of lowest OBL and LOBL EMG activityand highest RC EMG activity in the ES version (compared tothe NES version). A majority of these results belong to thetwo singers with marked highest body mass index in this inves-tigation (Table 1; singers 4 and 7).

DISCUSSION

The main finding in this investigation is that classical singersalter their breathing pattern when vocalizing with ES comparedto vocalizing with NES. Noticeable features in the ES versionare that, for the group, the correlation coefficients for LTX/ABD versus LOBL channels are marked lower (Figure 2A)and the correlation coefficient for ABD versus RC channels ishigher (Figure 2B). The latter result is not statistically proven asa group result for all vocalization tasks. Yet, increased ABD/RCcorrelation coefficients in the ES mode of vocalization are

observed in individual results (female singer, illustrated in Fig-ure 3) and for the group in four of the sample performances (themiddle and highest of the extreme tones, arpeggio, and glis-sando). Negative correlation coefficients between EMG andstrain gauge channels would in most cases denote increasingmuscle activity simultaneously with a diminishing circumfer-ence of the region mapped by the strain gauge sensor. Corre-sponding positive correlations would suggest decreasingEMG activity as the circumference of the strain gauge sensordiminishes. Accordingly, the group result implies that singingwith ES facilitates (1) an increased contribution from theLOBL muscles in slowing down the compression of especiallyLTX, but also ABD and (2) a decreased contribution from theanterior abdominal muscles (RC) in the positioning of the ab-dominal wall during phonation (illustrated in Figure 3). Watsonet al11 reported that abdominal activation during singing isclearly regional. Specifically, the lateral region of the abdomen(OBL and LOBL) is highly active, whereas the middle region(RC) is not. EMG activity in the lateral region was character-ized by higher activity in the lower portion (LOBL) relativeto the upper portion (OBL). In the study by Watson et al, songswere performed and an emotional connection during perfor-mance is expected. Therefore, the findings in their study areparallel to those in this study. Singing with ES facilitates theLOBL muscles a more significant role, and the anterior abdom-inal muscles (RC) a less significant role, in breathing for clas-sical singing.

Within the group, correlation coefficients varied betweensingers (as would be expected) and within singers in the 16 sam-ple performances (eight singing with NES and eight singingwith ES). The female singer illustrated in Figure 3 altered herpattern of breathing support from ‘‘belly-out’’ (singing withNES) to ‘‘belly-in’’ (singing with ES). The ‘‘belly-out’’ condi-tion was characterized by sustained EMG activity in RC andan expansion of ABD during a part of the glissando. The‘‘belly-in’’ condition (singing with ES) was characterized byan outburst of EMG activity (close to 40% EMGmax) in theLOBL site as ABD was compressed, whereas LOBL activitywas negligible during the belly-out condition. A voluntarychange in breathing pattern, from belly-out to belly-in would

TABLE 3.

Results of Wilcoxon Two-Related Samples Test (Two-

Tailed), Used to Test the Group Results of EMG Loading

Between the NES and ES Settings

Sample

Performance

(Task) Muscle

Median

Differences

(%EMGmax)

Test

Statistics

(Z)

Sig.

(Two-

Tailed)

Extreme tones

Middle INT 0.57 0 1.0

RC 0.76 1.69 0.091

OBL 4.63 1.863 0.063

LOBL �0.64 0.593 0.553

Highest INT 7.9 1.352 0.176

RC 2.2 �0.338 0.735

OBL 8.69 2.028 0.043*

LOBL 0.38 0.507 0.612

Lowest INT �0.15 �0.169 0.866

RC 1.65 �0.338 0.735

OBL 1.26 0.845 0.398

LOBL �1.7 0.851 0.395

Swell tones

Middle INT 2.4 0.105 0.917

RC 0.37 0.917 0.105

OBL 0.93 �1.014 0.310

LOBL �0.25 0 1.0

Highest INT �0.33 �0.507 0.612

RC �0.84 �0.1753 0.08

OBL 0.68 0.676 0.499

LOBL �0.83 0.169 0.866

Lowest INT 1.3 0.734 0.463

RC �0.12 �0.169 0.866

OBL �0.18 �0.676 0.499

LOBL �0.78 0.735 0.463

Arpeggio

INT 0.36 1.352 0.176

RC 1.28 0.944 0.345

OBL 1.8 1.014 0.31

LOBL 0.64 �0.1951 0.051

Gilissando

INT 0.77 0.085 0.933

RC �1.1 �0.1156 0.248

OBL �0.34 �0.676 0.499

LOBL 0.16 �0.314 0.753

Significance at alpha level 5% is marked with an asterisk.

Journal of Voice, Vol. 23, No. 3, 2009302

normally not occur by experienced classical singers. Thomas-son and Sundberg12 found high consistency in the classicalsingers’ breathing behavior when tasks were repeated. In thestudy of Thomasson and Sundberg, tasks were repeated withoutchanging any of the parameters during performances. In ourstudy, the mode of singing was changed when tasks were re-peated. Yet, two male singers (illustrated in Figure 5) fit intothe description of showing high consistency in breathing behav-ior when sample performances are replicated. Nevertheless, theremaining five singers did change their breathing pattern in theES mode. It may be hypothesized that this shift in breathing be-havior is corresponding to what young classical singers often

experience when performing in front of an audience: The stagearousal and involvement in text and music make them sing bet-ter than they expected. Simultaneously, they experience thatthey carry out their breathing support in an unfamiliar way,compared with what they have been rehearsing. One reasonfor this may be that the emotional aspect of performing oftenis underestimated when breathing behavior is drilled by vocal-izing exercises and technically demanding aria segments. Thus,breathing for singing may be wrongly learnt and accordingly, beof limited benefit when songs and arias, demanding involve-ment from text and music, are interpreted.2

A methodological concern is, firstly, that we do not know ifthe individual singer managed to keep a focus on an emotionalconnection when performing in the ES modus. Secondly, the fo-cus on the emotional stimulus used for ES, chosen individuallyby the singer, could vary between sample performances. Thus,we do not know to what degree a change in breathing patternfrom one sample performance to another is because of a changein emotional stimulus. Neither do we know if different degreesof pattern changes between singers are caused by different de-grees of emotional stimulus. Some studies have shown thatsingers (professionals and students) alter their patterns ofbreathing when one degree of freedom is influenced from onesinging performance to another.10,13 The mental state when per-forming would also be one degree of freedom. As a singer’semotional state would vary between sample performances,due to instructions from researchers and the distraction fromthe recording procedure itself, there is no way of securinga mental setting that will be locked throughout the entire re-cording session. It is also evident that singers normally performwith different degrees of emotional arousal on stage.2,14

Thirdly, two of the male singers did not alter their breathing pat-tern when performing in the ES mode. We do not know if thesetwo singers, due to previous vocal training were taught to al-ways focus on emotions when performing exercises, and there-fore, would not vary considerably in emotional stimulusbetween sample performances. Finally, a methodological con-cern is also the lack of consensual conceptualization amongsubjects on what emotions to focus on. The emotional associa-tion used in ES was determined by the individual singer her/himself, therefore, the state of ES would vary between the sevensingers. Studies have shown that it is possible to distinguish be-tween vocal expressions of different emotions.15 Nevertheless,Scherer16 claims that even if researchers provide subjects withmore or less standardized lists of emotion labels, several seriousdisadvantages exist: One of the major ones is the possibility thatone or several alternatives may ‘‘prime’’ the subjects, that is,suggest feelings they might not have chosen otherwise. The op-posite problem is that a subject might want to respond witha category that is not provided by the researcher, thus forcingthe subject to respond with an alternative, with the specificityand accuracy of data suffering as a sincere consequence.Such, given that students are sensitive to all kind of instructions,due to their everyday life of constantly trying to improve sing-ing skills, an over focusing on a special emotional state wouldprobably be more harmful to the intention of the performances,than serving as clarification. Besides that, the aim of the study

Viggo Pettersen and Kare Bjørkøy Emotional Stimulus on Breathing for Singing 303

was to investigate if emotions in general affect muscle activitypatterns and trunk movement in breathing for singing. As theconcerns above would be in evidence in professional classicalsinging and in classical students’ singing, in general, it is reasonto believe in the results.

It is interesting that some singers respond to a rather simple in-struction on connection of emotions by altering their breathingpattern radically. Presumably, these singers did not have an en-hanced awareness of the way they normally conducted theirbreathing and, therefore, responded the way they did. This is inaccordance with the findings of Watson and Hixon,17 who founda discrepancy between how subjects thought they breathed dur-ing classical singing and how they actually breathed. The findingof an increased activation of the LOBL muscles, in the ES ver-sion of vocalization, could suggest that the breathing supportwas adjusted to provide a needed assistance for an intendedemotional expression, as found by Thorp et al.18

For the group, EMG loading did not considerably vary be-tween singing with NES and singing with ES (Table 3). Never-theless, individual results show that the two singers loweringlateral abdominal EMG activity (OBL and LOBL) and increas-ing anterior abdominal EMG activity (RC) in the ES versionhave marked highest body mass index (Table 1; singers 4 and7) among all singers in this investigation. Thus, some of the re-sults suggest that singers with high body mass index respondeddifferently from the rest of the singers on the shift from singingwith NES to singing with ES. Hixon et al19 stated that breathingfor singing could be conducted in different ways with respect tobody shapes. This issue is little researched, and future researchto explore breathing for singing and body shapes would be ofsignificant importance for singing teachers and for singers.

The aim of the study was to investigate the effect from ES onthe correlation between INT/abdominal muscle activity and trunkwall movement. Even though the use of emotional stimulus in theES sample performances must be considered as moderate, the re-sults indicate that the performing state of mind must not be under-estimated when training for enhanced technical skills in classicalsinging. If the studio training aims to approach the state of mindexperienced on stage, studio performances should be conductedin manners that facilitate the use of emotional stimulus whenperforming even simple vocalization exercises.

CONCLUSION

The main finding in this investigation is that classical singersalter their breathing pattern when they vocalize using ES

compared with using NES. For the group, LTX/ABD versusLOBL channels are negatively correlated and correlation coef-ficients are marked lowest in the ES version. The results implythat vocalizing using ES facilitate a more prominent role forLOBL activity in the positioning of the abdominal wall andthorax than observed for vocalizing using NES.

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