Active self correction of back posture

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Manual Therapy 19 (2014) 392e398

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Manual Therapy

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Original article

Active self-correction of back posture in children instructedwith ‘straighten your back’ command

Dariusz Czaprowski a,b,*, Paulina Paw1owska a, qukasz Stoli�nski b, Tomasz Kotwicki c

aDepartment of Physiotherapy, Józef Rusiecki University College, Bydgoska 33, 10-243 Olsztyn, PolandbRehasport Clinic, Pozna�n, PolandcDepartment of Pediatric Orthopedics and Traumatology, University of Medical Sciences in Pozna�n, Poland

a r t i c l e i n f o

Article history:Received 5 December 2012Received in revised form12 October 2013Accepted 21 October 2013

Keywords:Self-correctionBody postureSpine curvatures

* Corresponding author. Department of PhysiotherCollege, Bydgoska 33, 10-243 Olsztyn, Poland. Tel./fax

E-mail address: [email protected] (D.

1356-689X/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.math.2013.10.005

a b s t r a c t

The ability to adopt the properly corrected body posture is one of the factors determining the effec-tiveness of therapeutic programmes. This study determined the active self-correction expressed by thechange of sagittal spinal curvatures (in standing and sitting positions) in 249 children (136 females, 113males, aged 10e14 years) instructed with ‘straighten your back’ command (SYB). Spinal curvatures(sacral slope-SS, lumbar lordosis-LL, global, lower and upper thoracic kyphosis-TK, LK, UK, respectively)were assessed using Saunders inclinometer. The assessment was done in spontaneous standing andsitting positions and in the positions adopted after the SYB.

In a standing position SYB led to the significant (P < 0.001) increase in SS, and the significant (P < 0.01)decrease in LL, TK, LK, UK. In a sitting position SYB led to significant changes (P < 0.001) from kyphotic tolordotic position of SS and LL and to the significant (P < 0.001) reduction of TK (36.5� � 10.8 vs.23.5� � 11) and the flattening of LK (15.2� � 8.7 vs. 1.0� � 8.4). There were gender-based discrepancyregarding active self-correction only for LL in a standing and UK in a sitting position. Females demon-strated a significant decrease in LL (P < 0.001). UK significantly increased only in males (P < 0.001).

The ‘straighten your back’ command leads to moving the spine away from mid-range towards endrange of motion. Therefore, the command should not be used to elicit the most optimal back posture.Further studies are needed to determine if the active self-correction is different in females and males.

� 2013 Elsevier Ltd. All rights reserved.

1. Introduction

‘Good’ posture is the complex interplay between biomechanicaland neuromuscular functions which safely loads spinal segmentsand conserves energy (Claus et al., 2009a). Although it is widelyaccepted that a ‘good’ posture is vital for proper functioning of thebody, it proves to be difficult to define by means of quantitativefactors (Claus et al., 2009a).

One of the basic features determining the quality of bodyposture is spinal curvatures in sagittal plane (Kendall et al., 2005). Itis suggested that a correct standing position should involve slightlumbar lordosis and slight thoracic kyphosis (Kendall et al., 2005).Kyphotic shape of lower thoracic kyphosis is of importance as wellsince it serves an important role in maintaining rotational stabili-sation of the spine (Kotwicki, 2002). However, it seems to be moredifficult to define the optimal sitting position. Some authors claim

apy, Józef Rusiecki University: þ48 89 5260400.Czaprowski).

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that spinal curves in sitting should be similar to “ideal” standingposition (Lee, 2003; O`Sullivan, 2004; Claus et al., 2009a).

Currently, a number of children and youth are being diagnosedwith postural faults as well as back and neck pain (Jones andMacfarlane, 2005; Kendall et al., 2005; Geldhof et al., 2007). Onereason, among other factors, may be prolonged poor sitting(Murphy et al., 2004; Geldhof et al., 2007). Prolonged sitting hasalso been reported to be a common aggravating factor for subjectswith low back pain (LBP) (Williams et al., 1991). Commonly adoptedrelaxed postures (sway standing, slump sitting) has been also re-ported to frequently exacerbate LBP (O`Sullivan, 2000; O`Sullivanet al., 2002). Therefore, youths can be referred to various thera-peutic programmes aimed at improving the quality of body posturealong with fostering the awareness of the importance of correctposture when sitting and standing (Geldhof et al., 2007). Teachingthe appropriate active self-correction might be one of the elementsof such programmes (Weiss et al., 2006; Romano et al., 2008). Ac-cording to Weiss et al. (2006) the ability to adopt and maintain theproperly corrected body posture whilst completing activities ofdaily living is one of the factors determining the effectiveness ofcorrective programmes concerning the improvement of body

D. Czaprowski et al. / Manual Therapy 19 (2014) 392e398 393

posture. Active self-correction is also an essential part of the pro-gramme of conservative treatment for idiopathic scoliosis (Romanoet al., 2008; Zaina et al., 2009) which may prove that the quality ofperforming active self-correction is important.

Giving different commands such as ‘straighten your back’mightbe one of the ways of improving one’s body posture. The commandis used during therapeutic sessions as well as included in guidanceprovided by a physiotherapist (Buli�nska, 2005). Our experience andobservations show that it is also commonly given by parents andteachers. However, it has not been yet determined whether sub-jects following the aforementioned command adopt an optimalposition of the spine and hence whether the instructions proveuseful in improving the quality of body posture in youths.

The aim of this study was to determine the active self-correctionexpressed by the change in the magnitude of spinal curvatures inthe sagittal plane both in standing and sitting positions in childrenaged between 10 and 14 years instructed with ‘straighten yourback’ command. As yet there have been no studies examiningwhether females and males perform active self-correction differ-ently, we have additionally conducted the assessment of changes insagittal curvatures of the spine in individuals instructed with‘straighten your back’ command for females and males separately.

2. Material and methods

2.1. Subjects

The recruitmentof the subjects to the study tookplaceduring thepresentations for parents and their children. Thepresentationsweregiven in 5 randomly selected primary schools. The informationabout the study was placed on notice boards and school websiteswith the school master’s consent. 450 parents and their childrenparticipated in the meetings. Finally, the study included 249 chil-dren (136 females and113males) aged10e14 years (11.8� 0.8),whomet the following criteria:written informed consent of parentswhoallowed their children to participate in the study, no participation incorrective gymnastics classes, no previous guidance on how to ac-quire the correct posture, no neurological disorders, injuries ormusculoskeletal pain in the preceding 12 months. The basic de-mographics of the study group are given in Table 1.

2.2. Measurement protocol

2.2.1. Evaluation of sagittal curvatures of the spineAll of the children underwent the evaluation of spinal curvatures

in sagittal plane. The assessment was carried out with Saundersinclinometer (Baseline Digital Inclinometer, The Saunders GroupInc, Chaska, MN, USA). The measurements were conducted ac-cording to the producer’s instructions following the AmericanMedical Association guidelines (Saunders, 1998; Andersson andCocchiarella, 2004). Prior to measurements, a non-toxic skinmarker was used to mark the following measurement points foundby palpation (Muscolino, 2008; O`Sullivan et al., 2010): lumbosacraljunction e L5/S1 (LS point), thoracolumbar junction e T12/L5 (TLpoint), cervicothoracic junction e C7/T1 (CT point) and T6/T7junction (T6 point) (Fig. 1). In order to assess the angle of sacral

Table 1Demographics of the study group (n ¼ 249).

Mean Minimum Maximum SD

Age (years) 11.8 10.0 14.0 0.8Height (m) 1.51 1.3 1.74 0.1Weight (kg) 44.4 21.0 72.0 10.2BMI (kg m�2) 19.2 11.0 35.1 4.0

slope, the inclinometer was reset in the horizontal position andplaced on the LS point. The angle of lumbar lordosiswas determinedafter the inclinometer was reset at the LS point and the reading wastaken at the TL point. The measurement of global thoracic kyphosisangle started with resetting the inclinometer at the TL point andthen itwas applied to CT point. Additionally, themagnitude of lower(T6/T7eT12/L1) and upper thoracic kyphosis (C7/T1eT6/T7) wasdetermined. The inclinometer was placed on the TL point, afterwhich it was reset and applied to T6 point to determine themagnitude of lower thoracic kyphosis. In order to assess the upperkyphosis, the inclinometer was reset at the T6 point and placed atthe CT point. Each measurement was carried out three times. Theaveragevalues of the threemeasurementswereused for the analysis(Saunders, 1998; Andersson and Cocchiarella, 2004).

The assessment of sagittal curvatures of the spine was carriedout with subjects in spontaneous standing and sitting positions andthe position adopted after the ‘straighten your back’ command. Thefirst measurement was carried out in a standing position. Thesubjects were neither provided with any guidance nor received anyfeedback on their posture. Kyphotic curves were represented aspositive angles, whereas lordotic curves were recorded as negative(Claus et al., 2009a).

All the measurements were performed by one investigator.

2.2.2. Measurement of sagittal curvatures of the spine in a standingposition

The assessment was conducted with subjects in a spontaneousstanding position, shoeless (O`Sullivan et al., 2002). Their lowerlimbs were extended at the knee joint, with feet hip-width apart.The upper limbs were relaxed at the side of the body. Subjects wererequested to view a designated point ahead at eye level.

First, the magnitude of sagittal curvatures of the spine wasmeasured with subjects standing in a habitual, spontaneous posi-tion, in line with the above mentioned methodology. Immediatelyafterwards, every subject was given the ‘straighten your back’command and after 5 s the measurement was taken (Fig. 2).

2.2.3. Measurement of sagittal curvatures of the spine in a sittingposition

The examination was conducted on a therapeutic table with asubject in a sitting position, with no back support. The height of thetable was adjusted to every subject individually to achieve themostnatural and comfortable position. The height of the seat wasadjusted to the posterior knee crease level to achieve the flexion ofhip and knee joints at 90� (Claus et al., 2009a). The positions of hipand knee joints were verified with a goniometer. The subject’shands rested on laps and their feet rested on 20-cm high box.

Every subject was requested to adopt a relaxed, spontaneousposition after being instructedwith ‘sit as you usually do’ command(O`Sullivan et al., 2010). Subjects were also requested to view adesignated point ahead at eye level (Caneiro et al., 2010; O`Sullivanet al., 2010). After 5 s, spinal curvatures were measured followingthe aforementioned measurement guidelines. Afterwards, thesubjects were instructed with ‘straighten your back’ command and,after 5 s, the measurement was repeated (Fig. 3).

2.2.4. Active self-correction evaluationIn order to determine the effect of active self-correction, the

angular values of each spinal curvature were compared in differentpositions: spontaneous standing and sitting positions as well aspositions adopted after ‘straighten your back’ command. The re-sults obtained during the examinations were compared for thewhole group as well as for females and males separately.

The local Ethical Commission granted permission for thisresearch (permission number: 2/2012).

Fig. 1. Location of the measurements points. LS e lumbosacral junction, TL e thor-acolumbar junction, T6 e T6/T7 junction, CT e cervicothoracic junction.

D. Czaprowski et al. / Manual Therapy 19 (2014) 392e398394

2.2.5. Pilot reliability studyThe reliability of themeasurements performed in a spontaneous

standing position expressed by Cronbach’s alpha coefficient was asfollows (Czaprowski et al., 2012): (1) 0.85 for sacral slope; (2) 0.87for lumbar lordosis; (3) 0.83 for thoracic kyphosis; (4) 0.82 forlower thoracic kyphosis; and (5) 0.86 for upper thoracic kyphosis.That indicates good reliability of the measurement (Bland andAltman, 1997; Czaprowski et al., 2012). The measurement errorwas calculated at (1) 3.3�; (2) 3.2�; (3) 3.8�; (4) 3.3�; and (5) 2.8�,respectively (Czaprowski et al., 2012). Additionally, prior to thestudy, reliability of measurements and measurement error forspontaneous sitting positionwere assessed. The reliability level andmeasurement error were as follows: (1) 0.89 and 2.3�; (2) 0.99 and2.5�; (3) 0.91 and 1.9�; (4) 0.97 and 2.5�; (5) 0.97 and 1.7� for sacralslope, lumbar lordosis, thoracic kyphosis, lower thoracic kyphosis,and upper thoracic kyphosis, respectively. That indicates excellentand good reliability of these measurements (Bland and Altman,1997).

2.3. Statistical analysis

Statistical analysis was performed with Statistica 7.1 (StatSoft,Poland). The ShapiroeWilk test determined the normal distribu-tion of the data. The Wilcoxon test was used to determine differ-ences (in the whole group of children) for five spinal angles (sacralslope, lumbar lordosis, thoracic kyphosis, and its lower and upperpart) evaluated before and after `straighten your back’ command.The analysis was performed for standing and sitting positionseparately. Apart from the analysis carried out for the whole groupof children, additionally, the same analysis procedure was repeatedfor females andmales separately. The value P¼ 0.05 was adopted asthe level of significance.

3. Results

3.1. Standing position e the whole group

The average magnitude of thoracic kyphosis in a spontaneousstanding position was 42.7� � 9.3 in the whole group and itdecreased significantly (P < 0.001) after the ‘straighten your back’command. A significant decrease was also observed in lower andupper kyphosis (P < 0.001) as well as in lumbar lordosis (P < 0.01).The sacral slope significantly increased after the `straighten yourback’ command (P < 0.001) (Table 2).

3.2. Sitting position e the whole group

A significant (P < 0.001) change from kyphotic to lordotic po-sition in sacral slope and lumbar lordosis was observed after`straighten your back’ command. Thoracic kyphosis and its lowerpart significantly (P < 0.001) decreased (from 36.5� � 10.8 to23.5� � 11.7 and from 15.2� � 8.7 to 1.0� � 8.4, respectively). Upperthoracic kyphosis significantly increased (P < 0.001) after thecommand (Table 2).

3.3. Standing and sitting positions e females

In females, in a standing position, after `straighten your back’command, a significant (P < 0.001) increase of sacral slope wasobserved. The other parameters significantly (P< 0.001) decreased.In sitting, a significant (P < 0.001) change from kyphotic to lordoticposition of sacral slope and lumbar lordosis was observed. Thoracickyphosis and its lower part significantly (P < 0.001) decreased.Upper thoracic kyphosis did not change significantly after thecommand (Table 3).

Fig. 2. A e spontaneous, habitual standing posture, B e standing posture adopted after ‘straighten your back’ command.


3.4. Standing and sitting positions e males

Inmales, in a standing position, a significant (P< 0.001) increaseof sacral slope was observed after ‘straighten your back’ command.

Fig. 3. A e spontaneous, habitual sitting position, B e sitting

Thoracic kyphosis and its lower and upper parts significantly(P< 0.001) decreased after the command. Lumbar lorodosis did notchange significantly. In sitting, a significant (P < 0.001) change ofsacral slope and lumbar lordosis from kyphotic to lordotic position

position adopted after ‘straighten your back’ command.

Table 2Change in spinal curvatures in sagittal plane in standing and sitting - the whole group (n ¼ 249).

Parameter Spontaneous standing position Corrected standing position Spontaneous sitting position Corrected sitting position

Mean� Median Mean� Median Mean� Median Mean� Median

Sacral slope (L5/S1-horizontal line)� �19.3 � 6.3 �20 �21.5 � 7.1 �21** 11.4 � 9.0 12 �7.1 � 8.2 �8**Lumbar lordosis (T12/L1eL5/S1)� �33.0 � 13.0 �33 �31.3 � 10.3 �31* 17.4 � 12.1 18 �6.6 � 10.5 �6**Thoracic kyphosis (C7/T1eT12/L1)� 42.7 � 9.3 42 33.2 � 11.6 33** 36.5 � 10.8 36 23.5 � 11.7 23**Lower thoracic kyphosis (T6/T7eT12/L1)� 9.5 � 7.7 10 2.6 � 9.4 3** 15.2 � 8.7 16 1.0 � 8.4 1**Upper thoracic kyphosis (C7/T1eT6/T7)� 33.2 � 7.4 33 30.2 � 10.0 31** 21.1 � 8.5 21 22.0 � 11.6 22**

*p < 0.01; **p < 0.001; ‘e’ lordotic curve.

Table 3Change in spinal curvatures in sagittal plane in standing and sitting e females (n ¼ 136).



Sacral slope (L5/S1-horizontal line)� �21.3 � 6.0 �21.5 �22.7 � 6.7 �22.5** 9.4 � 8.4 10 �8.3 � 8.2 �9**Lumbar lordosis (T12/L1eL5/S1)� �34.5 � 8.7 �34 �31.9 � 10.1 �31** 15.2 � 12.1 16 �7.6 � 10.6 �7.5**Thoracic kyphosis (C7/T1eT12/L1)� 42.6 � 9.9 42 33.1 � 12.0 32** 36.6 � 11.4 37 22.8 � 11.6 21**Lower thoracic kyphosis (T6/T7eT12/L1)� 9.3 � 7.8 10 2.0 � 10.6 2.5** 15.5 � 9.2 16 0.5 � 8.7 1**Upper thoracic kyphosis (C7/T1eT6/T7)� 33.4 � 7.9 33 30.0 � 11.2 31.5** 20.7 � 8.7 21 20.7 � 12.4 21.5

**p < 0.001; ‘e’ lorodotic curve.


was observed. Thoracic kyphosis and its lower part significantly(P < 0.001) decreased after ‘straighten your back’ command. Upperthoracic kyphosis significantly (P < 0.001) increased (Table 4).

4. Discussion

The aim of the study was to determine the change in bodyposture expressed by the magnitude of sagittal curvatures of thespine in children instructed with ‘straighten your back’ command.Active self-correction was evaluated both in standing and sittingpositions. Due to the fact that so far there has been no analysisdetermining whether this movement is determined by the gender,the study additionally examined it for females and malesseparately.

Apart from the standard assessment of the magnitude of sacralslope, lumbar lordosis and thoracic kyphosis (Saunders, 1998;Andersson and Cocchiarella, 2004), the study also evaluated up-per and lower thoracic kyphosis separately. It stems from the factthat lower thoracic kyphosis is crucial to the rotational stabilisationof the spine and hypokyphosis of this part of thoracic spine istypical for progressive idiopathic scoliosis (Kotwicki, 2002). Studiesconducted by O`Sullivan et al. (2006) also assessed the magnitudeof lower thoracic kyphosis (T6eT12).

4.1. Standing position

In the whole study group, a significant change was observed inthe magnitude of all measured parts of the spine in subjectsinstructed with ‘straighten your back’ command. Thoracic kyphosisas well as its upper and lower parts along with lumbar lordosisdecreased whereas sacral slope significantly increased.

The obtained results indicate that the ‘straighten your back’command leads to the extension of the back expressed by thedecrease in the magnitude of kyphotic curves and the increase insacral slope.

4.2. Sitting position

It was typical for the whole study group, including both femalesandmales to acquire kyphotic posture (referred to as slump sitting)

in a relaxed sitting position (O`Sullivan et al., 2006; Caneiro et al.,2010). The ‘straighten your back’ command brought about aconsiderable change in position of the spine towards extensionwhat led to the decrease in thoracic kyphosis and its lower part aswell as the lordotic alignment of the lumbar spine and sacral slope.However, it seemsworth noting that the lumbar spine adopted onlya slightly lordotic position (median �6�) and lower thoracickyphosis was flattened (median 1�).

4.3. Females and males

In our studywe have observed a slight discrepancy in active self-correction performed by females and males. Females wheninstructed with ‘straighten your back’ command demonstrated asignificant decrease in lumbar lordosis whereas in males thisparameter did not undergo any changes. In turn, upper thoracickyphosis increased in both females and males. However, thischange was statistically significant (P < 0.001) in males only.Similar changes were observed in other parts of the spine in bothgroups. However, it is worth noting that in the present study therewas no direct comparison between genders. Therefore, furtherstudies are needed to determine whether the active self-correctionis the same or different in females and males.

4.4. Clinical relevance

Sitting is one of the risk factors contributing to low back pain.Therefore, re-education of sitting posture may be one of the stra-tegies of preventing and treating it (O`Sullivan et al., 2012). Yet, theoptimal sitting position is still the subject of ongoing discussions(Claus et al., 2009a; O`Sullivan et al., 2010). Unquestionably, varioussitting and standing postures affect the activity of trunk musclesand spinal load differently (O`Sullivan et al., 2002; O`Sullivan et al.,2006; Claus et al., 2009b). A number of authors recommendacquiring neutral spine position involving slight lumbar lordosisand a relaxed thorax for those LBP subjects who are sensitive tolumbar spine flexion and extension. This position enables subjectsto avoid pain resulting from adopting end-range positions and itfacilitates the adoption of the most desirable pattern of key trunkmuscles activation (Scannell and McGill, 2003; O`Sullivan et al.,

Table 4Change in spinal curvatures in sagittal plane in standing and sitting e males (n ¼ 113).



Sacral slope (L5/S1-horizontal line)� �17.1 � 6.1 �17 �20.2 � 7.3 �19** 13.8 � 9.2 15 �5.5 � 8.0 �5**Lumbar lordosis (T12/L1eL5/S1)� �31.2 � 8.5 �31 �30.7 � 10.6 �31 20.1 � 11.5 20 �5.4 � 10.2 �5**Thoracic kyphosis (C7/T1eT12/L1)� 42.9 � 8.7 43 33.5 � 11.4 36** 36.5 � 10.1 36 24.3 � 11.8 24**Lower thoracic kyphosis (T6/T7eT12/L1)� 9.8 � 7.6 10 3.4 � 7.7 3** 14.9 � 8.2 16 1.4 � 8.1 1**Upper thoracic kyphosis (C7/T1eT6/T7)� 33.1 � 7.0 32 30.4 � 8.4 31** 21.6 � 8.2 21 23.5 � 10.4 24**

**p < 0.001; ‘e’ lorodotic curve.


2006; Claus et al., 2009b). However, according to Claus et al.(2009a) the adoption of such a position might prove difficult andtherefore it calls into question whether it might be used in clinicalpractice.

According to Claus et al. (2009a), four types of sitting posturescan be distinguished by the direction of curve at thoraco-lumbarand lumbar angles: (1) slump (thoraco-lumbar and lumbar spinein a kyphotic position), (2) flat (thoraco-lumbar and lumbar spinein a vertical position), (3) long lordosis (thoraco-lumbar and lumbarspine in a lordotic position) and (4) short lordosis (thoracickyphosis and lumbar lordosis). Short lordosis is suggested as ‘ideal’since it helps achieve proper spinal curves in standing (Claus et al.,2009a). This position divides the direction of spinal curvaturesbetween thoracic and lumbar spine. Caneiro et al. (2010) andO`Sullivan et al. (2006), in turn, proposed three thoraco-lumbarsitting postures: (1) slump sitting (posterior rotation of the pelvis,thoraco-lumbar spine relaxed while looking straight ahead), (2)lumbo-pelvic upright sitting (anterior rotation of the pelvis in orderto achieve a neutral lordosis of the lumbar spine and relaxation ofthe thorax) and (3) thoracic upright sitting (anterior rotation of thepelvis, thoraco-lumbar spine extended with shoulder bladesslightly retracted).

Taking into consideration the above mentioned descriptions itcan be assumed that two types of postures appeared in our study,namely slump sitting adopted before and long lordosis adoptedafter the ‘straighten your back’ command (Claus et al., 2009a) orthoracic upright sitting (O`Sullivan et al., 2006; Caneiro et al., 2010).The thoracic upright position is connected with an increased ac-tivity of thoracic erector spinae at T4 level and iliocostalis long-issimus pars thoracis. Therefore, it might lead to the higher risk ofgreater stress to articular and ligamentous structures, greatercompression load on cervico-thoracic spine as well as potentialdiscomfort (Lander et al., 1987; O`Sullivan et al., 2006; Claus et al.,2009a, 2009b; Caneiro et al., 2010).

Neutral position of the spine, in turn, increases trunk musclesactivity without activating large, torque-producing muscles(O`Sullivan et al., 2006; Claus et al., 2009b; Reeve and Dilley, 2009;O`Sullivan et al., 2010). Such a position also modifies the activity ofkey cervico-thoracic muscles which might be of importance inmaintaining the correct sitting posture without the excessivemuscle activity (O`Sullivan et al., 2006; Falla et al., 2007; Claus et al.,2009b; Caneiro et al., 2010).

What is also interesting is that physiotherapists most frequently(54.9%) indicate that lordosed lumbar spine posture together withrelaxed thoracic spine is the best sitting position (O`Sullivan et al.,2012). Our study found that the ‘straighten your back’ commandbrings about the adoption of a different position. Subjects assumedthe posture in which lumbar and thoracic spine was extended.

Taking into consideration the results of this study, it seems thatthe ‘straighten your back’ command should not be used to elicit themost optimal posture. Children who are not provided with anyguidance on the appropriate active self-correction are not able to

adopt a neutral spine position when instructed with the command.Moreover, the assumed posture is characterised by the reduction oflower thoracic kyphosis which might mean moving further frommid-range and towards end range of motion. It is also confirmed byobservations made by Claus et al. (2009a) and O`Sullivan et al.(2010) who claim that the majority of people are not able to ac-quire short lordosis curves without facilitation and feedback and ifthe correction is made independently (without a therapist’s assis-tance) it is performed by extending the thoracic spine. This is all themore important that even slight changes of spinal curvatures insagittal plane and the subsequent deviations from the neutral po-sition may lead to the change in muscles activity and consequentlyto changes in spinal load (O`Sullivan et al., 2006; Claus et al., 2009b;Reeve and Dilley, 2009).

4.5. Limitations

The current study evaluated habitual standing and sitting po-sitions and an actively corrected posture adopted after ‘straightenyour back’ command. These positions might have been interpreteddifferently by individual subjects. However, the aim of our studywas not to determine the standard magnitude of spinal curvaturesin the adopted postures but to evaluate the change in sagittal spinalcurves in subjects instructed with the command. Therefore, webelieve that it did not influence the obtained results.

It is also worth noting that the extent of the differences betweensome values, despite being statistically significant, were small andin some cases only slightly over the standard error of measurement(SEM 2.8�e3.8� standing posture; 1.7�e2.5� sitting posture). Spe-cifically those for sacral slope, lumbar lordosis and upper thoracickyphosis performed in standing and upper thoracic kyphosismeasured in a sitting position (whole group) (Table 2). Therefore,these differences may not be clinically meaningful. Hence furtherresearch is needed to investigate whether the reported significantdifferences in those instances are merely the effect of the phe-nomenon of statistics or a true picture of ongoing changes.

In the instance of other measurements, namely thoracickyphosis and its lower part in standing as well as sacral slope,lumbar lordosis, global thoracic kyphosis and lower thoracickyphosis in sitting, the differences between individual measure-ments were large and they considerably exceeded themagnitude ofmeasurement errors. In our opinion it gives reason to believe thatthese differences may be clinically significant. Therefore, thefundamental observation we made concerning the reduction ofthoracic kyphosis and flattening of its lower part which occur inindividuals instructed with ‘straighten your back’ command both instanding and sitting positions is significant and may be applied inclinical practice.

The present study was conducted in a group of asymptomaticchildren aged 10e14 years. Therefore, caution is advised whentransferring the obtained results (especially the potential clinicalmeaningfulness) to other populations, e.g. children with


musculoskeletal pain or fatigue. Thus it is essential to undertakefurther studies to confirm the current study findings in pathologicalpopulations as well as those of younger or older children/youth.

Our study did not concentrate on evaluating the change in theposition of the head or trunk and neck muscles activity in theposture assumed after ‘straighten your back’ command. However,taking into consideration the relationship between head/neck po-sition and thoraco-lumbar posture it seems that a further studyshould be undertaken to determine the influence of the change inposition of one area of musculoskeletal system on the position andfunctioning of body parts further away. Especially as Caneiro et al.(2010) claim that management isolated in one segment mightprove less effective. Further studies might also be supplementedwith observations of changes in other than sagittal planes.

The majority of studies concerning various sitting and standingpostures concentrate on adults (O`Sullivan et al., 2002; O`Sullivanet al., 2006; Womersley and May, 2006; Claus et al., 2009a;Caneiro et al., 2010; O`Sullivan et al., 2010). Therefore, we shouldbe cautions when comparing the results of this study with resultspresented by other authors without previously comparing theactive self-correction between children and adults.

In spite of the limitations, we believe that the results of thestudy may have relevance to the clinical approach. Especially as thecurrent study included a large, homogeneous group of children andit is them who are frequently referred to various preventive andtherapeutic programmes (Geldhof et al., 2007).

5. Conclusions

The ‘straighten your back’ command brings about the extensionof the entire spine. This active self-correction appears in bothstanding and sitting positions. The reduction of global kyphosistogether with the flattening of its lower part, which was the resultof the command, calls into question whether the command shouldbe used to improve the body posture in children who were notprovided with any guidance on the correct shape of sagittal spinalcurves.

After ‘straighten your back’ command in a standing position, alumbar lordosis significantly changed (decreased) only in females,while upper thoracic kyphosis significantly changed (increased) insitting only in males. Therefore, further studies are needed todetermine whether the active self-correction is different in femalesand males.

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Health & Medicine

Active self correction of back posture