Logo Medical Science Monitor

Call: +1.631.470.9640
Mon - Fri 10:00 am - 02:00 pm EST

Contact Us

Logo Medical Science Monitor Logo Medical Science Monitor Logo Medical Science Monitor

29 July 2024: Database Analysis  

Impact of Standing and Sitting Postures on Spinal Curvature and Muscle Mechanical Properties in Young Women: A Photogrammetric and MyotonPro Analysis

Tomasz Sipko ORCID logo1ACDEF, Katarzyna Barczyk-Pawelec ORCID logo1ABCDEF, Mirela Piksa1ABCDEF, Joanna Mencel ORCID logo2CDEF*

DOI: 10.12659/MSM.944930

Med Sci Monit 2024; 30:e944930

0 Comments

Abstract

0:00

BACKGROUND: This study aimed to evaluate the effect of standing and sitting positions on spinal curvatures evaluated using projection moiré and muscle tone and stiffness using the MyotonPRO hand-held device in young women.

MATERIAL AND METHODS: Thirty-three healthy women, aged 21 to 23 years, volunteered in the study. We used the projection moiré method to examine spinal curvatures in both positions and the MyotonPRO device to measure the tone and stiffness of muscles in 3 regions. We evaluated the effects of positions (standing vs sitting), regions (cervical, thoracic, and lumbar), and side factor (right vs left) using multivariate analysis.

RESULTS: The sitting position significantly decreased the lumbosacral and thoracolumbar angles (P<0.001), but had no effect on the superior thoracic angle. Muscle tension and stiffness were the highest (P<0.001) in the cervical region and did not differ between positions (P>0.05) in this region. We found significantly higher muscle tone and stiffness in the thoracic and lumbar regions during sitting than during standing (P<0.001). There was symmetry in the muscle tone and the stiffness between the right and left sides of the spine.

CONCLUSIONS: The sitting posture decreased lumbosacral and thoracolumbar angles but increased muscle tension and stiffness in the lumbar and thoracic regions only. The symmetry of muscle tone and transverse stiffness in both positions was the normative value. This study provides insight into the adaptive physiological changes in spinal curvature and muscle mechanical properties in young women and serves as an important reference point for clinical studies of women.

Keywords: Posture, postural balance, Muscle Tonus, Hardness, Postural Asymmetry Factor

Introduction

Well-established knowledge indicates that postural control during quiet standing or sitting involves active sensory processing, with a constant mapping of perception to action, so that the postural system is able to calculate position of the body [1]. It is also well known that sensory inputs are critical to muscle tone and that postural tone is referred to activity in antigravity postural muscles to counteract the force of gravity [1].

Sedentary lifestyles and the prevalence of back pain provoke conducting research in this area in the context of evaluating the properties of the trunk muscles in different body positions. For example, the study of Zadoń et al [2] showed that adopting a sitting position increases lumbar spine load and erector spine and abdominal muscle activity, compared with the standing position, which is caused by changes in pelvis position and the curvature of the lumbar region.

One of the methods of objective posture assessment is the photogrammetric method, which uses the phenomenon of projection moiré [3]. Obtaining a spatial image in this method is possible because the device “projects” lines on the patient’s back, which are distorted, and, thanks to algorithms, are processed into a contour (height) map of the examined area. In addition, it is a non-invasive test conducted using visible light, with no quantitative limitations, unlike other methods, such as radiology [4]. For the sagittal plane, the resolution resulting from the density of the lines, accuracy of the calculations, and approximating functions used is at the level of 1 mm or 1° [3]. Based on this method, previous studies have indicated that the standing and sitting positions alter spine alignment, with habitual adopting of sitting postures giving rise to a kyphotic posture in asymptomatic women [5]. Accordingly, it has been postulated that correction in the active sitting position involves positioning of the pelvis in a forward tilt, resulting in a lordosis shape in the lumbar and cervical regions while maintaining a slight thoracic kyphosis [6]. From a biomechanical point of view, the shape of the lumbar lordosis should be similar to the curvature in a standing position, with thoracic kyphosis and head positioning in retraction rather than protraction in the optimal sitting position [7].

There was a substantial difference found between slouched and erect postures in male workers, with slouching being one of the risk factors involved in musculoskeletal pain around the scapulae [8]. Moreover, a rounded shoulder posture was characterized by a lower tone in the upper trapezius muscle, compared with normal shoulder posture in sedentary, asymptomatic workers [9]. An abnormal cervicothoracic posture in the sitting position causes greater neck flexion angle, increasing trapezius muscle stiffness, which is higher on the non-dominant side than on the dominant side in healthy adults [10]. In contrast, no significant differences were found between the mechanical properties of the left and right sides of the muscles in the cervical and lumbar region in axial patients with spondyloarthritis and healthy middle-aged adults in the prone position [11]. Based on the findings outlined above, symmetry and proper spinal muscle tone and stiffness should indicate optimal posture in various body positions. This corresponds with the results of study by Li et al [12], which indicated higher stiffness of the lumbar erector spinae muscle on the painful side, compared with the non-painful side in people with low back pain.

Stiffness is the biomechanical property of muscles that makes them resistant to external force that modifies their initial shape. Muscle stiffness of an appropriate level is necessary to maintain dynamic stability, and it has been shown that active muscle stiffness is vital in ensuring greater joint stability and preventing unfavorable factors that can lead to traumatic joint displacement [13]. If the stiffness is too high, there is an increased risk of injury due to reduced flexibility, and the risk of muscle weakness increases if the stiffness is too low [14]. Increased muscle tension leads to an increase in intramuscular pressure, impairing cardiovascular function and restricting blood flow to the muscles, which causes hypoxia and results in the process of muscle fatigue and slower recovery [15]. Excessive tension in one muscle interferes with the coactivation of antagonistic muscles, which consequently makes it difficult to perform daily activities, and can act as a risk factor for pain [16]. Long-term sitting or standing can affect the body, leading to many consequences, such as pain and discomfort [7].

The muscle tone and stiffness of the lumbar erector spinae were found to be significantly higher in male than in female participants and increased with age [15]. A study conducted by Mannion et al [17] confirmed sex-related differences in the muscle fiber size and type distribution in thoracic and lumbar regions of erector spinae in healthy participants. Another study also found a significant effect of age, sex, and adipose infiltration on the morphology of the paraspinal muscle [18].

One of the objective methods to assess the mechanical properties of muscles in a noninvasive way is myotonometry. The device used in this method, named MyotonPRO, applies brief mechanical impulses to the skin above the structure of interest (muscle, tendon, or fascia) to include its damped oscillation [19]. With the accelerometer placed in the device, different mechanical parameters, such as muscle tone (Hz) and transverse stiffness (N/m), are calculated. The validity and reliability of the method were already confirmed [12,20,21]. It has been shown that myotonometry can reliably measure transverse stiffness of the lumbar multifidus and longissimus thoracic muscles in healthy individuals in standing and squatting postures [21].

However, different authors emphasized the importance of considering factors such as age, sex, skinfold thickness, and body mass index (BMI) when assessing muscle properties using myotonometry [18,22–24].

The assessment of spinal curvatures and muscle tone and stiffness is clinically relevant, as lumbar and pelvic floor hypertonicity is often associated with low back pain and urological, gynecological, and gastrointestinal issues, particularly in women [25]. Sex-dependent differences suggest that the physiology of soft tissue structures can vary between healthy individuals, indicating the need for sex-specific analysis approaches [15]. In the multifactorial nature of low back pain, habitual, flexed sitting posture and the pressure pain threshold can be considered as predictive factors of low back pain in female office workers [6].

Therefore, in this study, we aimed to evaluate the effect of standing and sitting positions on spinal curvature evaluated using projection moiré and muscle tone and transverse stiffness using the MyotonPRO hand-held device in 33 women aged between 21 and 23 years.

We assumed that the tone and transverse stiffness of the spinal extensor muscles altered with changes in position, reaching higher values in the sitting position due to changes in the spinal curvatures and their level of activation. The symmetry of the muscle tone and transverse stiffness between the left and right sides of the spine were also investigated. We assumed no differences in the indicated comparison between the sides, owing to the inclusion of healthy, asymptomatic participants.

Material and Methods

ETHICS:

The Wroclaw University of Health and Sport Sciences’ Ethics Committee approved the study procedures (25/2016; 29/2013), and the study was conducted according to the World Medical Association Declaration of Helsinki. Approval was received based on the resolution of the Senate of the University of Physical Education in Wroclaw, dated December 20/2002, regarding the establishment of the Senate Committee on Ethics in Scientific Research, and the resolution of November 4/2003, governing the procedures, as well as in accordance with Article 27 of the Act of June 6/1997, the Code of Ethics (Journal of Laws of 1997, No. 553, as amended), and the principles outlined in “Good Practices in Science: A Collection of Principles and Guidelines” by the Ethics Committee in Science of the Polish Academy of Sciences from 2001. Before study initiation, each participants was informed about the form of the study and their right to refuse to participate or withdraw at any time. All participants provided written consent to participate in the study.

PARTICIPANTS:

Thirty-three healthy female students, aged 21 to 23 years, of the Physiotherapy Faculty at the Wroclaw University of Health and Sport Sciences volunteered to participate in the study. Their demographic characteristics are presented in Table 1. Only young, healthy women were included in the study, taking into account the factors that potentially affect the results [17,18,22–24]. The criteria for exclusion were injuries or pain in the spine or other parts of the musculoskeletal system, taking medication that affects the muscular and nervous systems, and overweight or obesity, indicated by BMI ≥25 [24].

PROCEDURES:

Because we conducted an observation study on a single group, we paid special attention to ensure that the course of the study was exactly the same in all participants. The examinations were conducted in the morning by the same 2 experienced physiotherapists. One of the physiotherapists was responsible for assessing the spine curvatures, the other for myometric measurements and anthropometric measurements. At the beginning, body weight and height measurements were made (Seca, Germany). For this step, it was necessary for participants to remove their shoes for all stages of the examination. The anthropometric measurements were taken in accordance with the International Society for the Advancement of Kinanthropometry guidelines, ensuring standardization of procedures [26]. The next steps took place after the back was exposed. The physiotherapist palpated and marked points on the back (needed for assessment of curvatures and mechanical properties of muscles; detailed description below) of the participants, who stood with their back to the physiotherapist. Then, the curvature of the spine was assessed in a habitual standing position. Next, the mechanical properties of muscles were assessed in the same position. After this part, the participants sat on a height-adjustable chair without a backrest, and the curvature of the spine was assessed in habitual sitting. Further, in this position, the mechanical properties of the muscles examined were assessed.

EXAMINATION OF THE CURVATURE OF THE SPINE:

The curvature of the spine was examined using the photogrammetric method based on the projection moiré phenomenon [3,4,27] using a fourth-generation moiré apparatus (CQ Elektronik System, Poland). The method allows mapping the anterior-posterior curvature of the spine. The moiré technique is based on the optical distortion created by the interference of light waves emitted from the device. Series of visible lines are projected onto the skin of the back (Figure 1), which are distorted at different angles depending on the distance of a given anatomical points from the projector, resulting in the ability to image the back with “depth” (dimples and convexities) and, as a result, anterior-posterior curvatures [28].

For this purpose, based on palpation assessment performed in the standing position [29], the bone points were marked on the skin with a washable medical skin marker. Dots were marked on the spinous processes of the vertebrae from C7 to S1, thoracic-lumbar transition (Th12/L1), base of the sacrum, inferior angle of the scapula, and posterior superior iliac spines. Standing posture was assessed in a habitual position with upper limbs placed along the trunk and lower limbs parallel to each other, without shoes. Each time, the participants stood in a designated place, positioning their feet in front of a line marked on the floor according to the procedure of this method [3]. A height-adjustable chair was used to assess habitual sitting posture, ensuring that the hip and the knee joints maintained a 90° angle (without shoes). The chair was positioned according to the course of the line mentioned above, for the same distance to the camera. The shape of the spine was recorded continuously for 5 s in both positions at a frequency of 4 Hz. From 20 images (5×4), one image was selected (devoid of movement artefacts, obtained during the participant’s exhalation, which can be determined from the spinal curvature pattern). Based on this image, the computer program calculated parameters describing body posture, along with a graphical representation of the results. Measurements were taken under strictly defined conditions: a constant distance of 2.6 m from the camera, which allowed the entire trunk to be captured and visible on the monitor screen, a completely darkened room, fixed optical system parameters, and precisely leveled camera [5].

Using the stored images, 3 parameters determining the anterior-posterior spine curvature were calculated:

Previous studies have shown that the photogrammetric method is effective and safe for assessing posture, and the results are similar to those obtained by the Cobb radiographic method [30]. The protocol outlined by Mrozkowiak [3], which was rigorously implemented and validated, affirmed the method and device’s reliability and standardization. The test-retest reliability of measuring habitual spinal posture in the standing and sitting positions was performed using interclass correlation coefficients (ICC2,1) and standard errors of measurement (SEM) in our earlier study [5]. Measurement reliability of the 3 conditions (habitual standing and sitting, as well as during active self-correction in response to the command “straighten your back”) were as follows: for the lumbosacral spine angle (α) – ICC=0.75–0.97 and SEM=0.70–5.51°; for thoracolumbar spine angle (β) – ICC=0.87–0.97 and SEM=0.62–1.36°; and for the upper part of the thoracic angle (γ) – ICC=0.86–0.96 and SEM=0.64–1.12° [5].

MEASUREMENTS OF MECHANICAL PROPERTIES OF MUSCLES:

Subsequently, the following measuring points were determined to evaluate the mechanical properties of the muscles in 3 regions: the apex of the lumbar lordosis, the apex of the thoracic kyphosis, and the apex of the cervical lordosis. Then, from the line of the spinous processes, at the apexes of the aforementioned curvatures, 2 cm were measured to the right and left, and points were marked there with a marker to measure the mechanical properties of the muscles in the 3 regions, namely: cervical, thoracic, and lumbar (Figure 1). Please note that MyotonPRO technology is used to assess the mechanical properties of superficial muscles, tendons, and fascia [12]. The points we chose corresponded with those chosen by others, which most often relate to the properties of such structures as: for the cervical region, the cervical muscle [11], splenius capitis [31], or simply the neck region [32]; for the thoracic region, the trapezius muscle [8–10]; and for the lumbar region, the lumbar multifidus [31] or lumbar erector spinae [12], which is also called the lumbar spine [32] or lumbar muscle [11,12,15,34,35,41].

The probe of the MyotonPRO device was applied perpendicularly to the skin to the marked points, first to the right, then to the left side of the body from the cervical region, through the thoracic to the lumbar region. A mode of 3 mechanical compressions of the tissue was used to induce its dampened oscillations, which means that the device performs 3 compressions and obtains 3 independent results, from which the average value is used for further analysis. Two myometric parameters were used for further analysis of the muscle tone and transverse stiffness. The tone parameter is related to the frequency of the recorded oscillations and is therefore expressed in Hz. The second parameter is called the transverse muscle stiffness. This parameter characterizes the resistance of muscles to a deformation force acting across the muscle (the probe end is positioned perpendicular to the skin over the muscle under examination). In this case, due to the constant force exerted by the probe end of the MyotonPRO (pre-load 0.18 N+compression impulse 0.42 N=0.60 N), the path calculated from the acceleration-time graph after its transformation is used to calculate the parameter that is expressed in N/m.

Previous studies have indicated that MyotonPRO reliability was excellent (ICC >0.93) for all modes of measurements, including the single compression mode and the average of 3 compressions (which was used in the study) [33]. It was also shown that MyotonPRO was more reliable in repeated testing than tensiomyography on the skin above the erector spinae muscle at the L3–L4 levels in healthy adults [34].

STATISTICAL ANALYSIS:

All calculations and analyses were made using Statistica software (version 13.3; StatSoft Poland, Krakow, Poland). A sample size was calculated by performing a priori power analysis to avoid a type II error. Assuming a clinically significant effect size of a change of 2° in the angles of the spine [6], and based on data from previous studies of others about mechanical properties of erector spinae muscles [12,35,40], a sample size of 30 participants was calculated to be sufficient, with acceptable power (0.8) at P<0.05. The Shapiro-Wilk test was performed to estimate the distribution of values collected in the study. If the Shapiro-Wilk test shows statistical significance (P<0.05), this indicates a distribution different from the normal distribution. Based on the result of this test, a parametric repeated measures analysis of variance (ANOVA) was used to determine the effect of position (2: standing, sitting) × region (3: cervical, thoracic, lumbar)×side (2: right, left) on myometric parameters (separately for muscle tone and muscle transverse stiffness). ANOVA was also used to determine the effect of region (3: cervical, thoracic, lumbar)×position (2: sitting, standing) on calculated spine curvatures. The significance level was set at P<0.05, and the partial eta-squared (η2P) was used as a measure of effect size for tests described above, where threshold values of 0.01, 0.06, and 0.14 indicated a small, medium, and large effect, respectively [36]. The achieved powers of the results of the main tests were ≥0.94. Follow-up comparisons were conducted using Tukey’s post hoc test, with Bonferroni correction for multiple comparisons.

Results

MUSCLE TONE:

There was a significant effect of position, F(1, 32)=13.808, P=0.0008, η2P=0.301 and region F(2, 64)=42.982, P=0.00000, η2P=0.573, on muscle tone (Figure 2). There was also significant effect of interaction between region and side, F(2, 64)=9.4902, P=0.0003, η2P=0.228, on muscle tone. The analysis showed that side factor has no significant effect on muscle tone, F(1, 32)=0.17736, P=0.676, η2P=0.005.

Descriptive characteristics of the data for the muscle tone parameter are shown in Table 2. Tukey’s post hoc showed a significant difference in muscle tone between 2 positions (sitting vs standing) in the thoracic and lumbar regions. For those regions, higher muscle tone for the right side was found in the sitting position than in the standing position (P=0.049 and P=0.0001 for thoracic and lumbar positions, respectively). For the left side, there was significantly higher muscle tone in the standing than in the sitting position in the thoracic region.

The results of Tukey’s post hoc test has also indicated differences in muscle tone between regions. For all pair comparisons, the highest muscle tone was found in the cervical region (P<0.0001). Muscle tone was significantly higher in the thoracic than in the lumbar region for the right side in the sitting position (P=0.007), and for the left side in the sitting position (P<0.0001), as well as for standing (P<0.0001).

Pair comparisons for sides showed significantly higher muscle tone for the right than the left side in the lumbar region in the standing position (P=0.0025). For the other 5 pairs, no differences were found between the right and left sides (P>0.05).

MUSCLE TRANSVERSE STIFFNESS:

There was a significant effect of position, F(1, 32)=34.180. P<0.0001, η2P=0.516), and region, F(2, 64)=12.572. P=0.00002, η2P=0.282, on muscle transverse stiffness (Figure 3). There was also significant effect of interaction between position and region, F(2, 64)=12.129. P=0.00003, η2P=0.274, and region and side, F(2, 64)=9.1709. P=0.0003, η2P=0.222, on muscle transverse stiffness. The analysis has shown that the factor side has no significant effect on muscle transverse stiffness, F(1, 32)=0.28597. P=0.59651, η2P=0.008.

Based on Tukey’s post hoc test, we have found significantly higher muscle transverse stiffness in the thoracic and the lumbar regions in the sitting position than in the standing position (P<0.001), for measurements at both sides (right and left), while there were no differences in muscle transverse stiffness in the cervical region between positions (P>0.05). Descriptive characteristics of the data for the muscle transverse stiffness parameter are shown in Table 3.

The results of Tukey’s post hoc test also indicated differences in muscle transverse stiffness between regions. The highest muscle transverse stiffness was found in the cervical region (P<0.001). Muscle transverse stiffness was significantly higher in the thoracic than in the lumbar region at the left side in both positions (P=0.0001 and P=0.0002 for standing and sitting positions, respectively). For the right side, a significantly higher value for the thoracic than the lumbar region was found in the standing position (P=0.002).

Significance differences in muscle transverse stiffness between the right and left sides were found for 2 of the 6 comparisons. Significantly higher muscle transverse stiffness was found for the right side in the lumbar region (P=0.0126 and P=0.0069 for standing and sitting positions, respectively).

SPINE CURVATURES:

Results of ANOVA showed a significant effect on region, F(2, 64)=54.837, P<0.0001, η2P=0.631, position, F(1, 32)=40.593, P<0.0001, η2P=0.559, and interaction between these factors, F(2, 64)=21.958, P<0.0001; η2P=0.406, on α, β, and γ angles (Figure 4).

Tukey’s post hoc test indicated differences in the values of angles between measurements in the standing and sitting positions (P<0.001). Detailed analysis showed that the values of α and β angles were greater in the standing than sitting position (P=0.0001 for both comparisons), and no difference was found for the highest located γ angle between positions (P=0.58). The highest value among the 3 angles was found for the γ angle in both the standing and sitting positions.

Discussion

MUSCLE TONE AND TRANSVERSE STIFFNESS:

There were no significant differences in muscle tone and transverse stiffness between the left and right sides of the cervical and thoracic regions. The cervical spine was stable and balanced, with the highest muscle tone and transverse stiffness values in both body positions. These results correspond with knowledge of postural balance responses, which depend on the position of the head and cervical spine in space [1].

The tone and stiffness of the spinal erector muscle increased in the sitting position, with the highest values occurring in the cervical region. A previous study confirmed that an increase in muscle tone and muscle stiffness parameters could be used to assess spine stability [37]. Even a slight deviation from the natural axis of the spine leads to increased tension [38], while prolonged immobility leads to the accumulation of muscle metabolites and a subsequent increase in tension and stiffness, causing muscles to tire faster and weakening stabilization [39]. A forward-tilted head in a standing or sitting position leads to increased muscle activity, resulting in fatigue and greater stiffness. In addition, muscles had higher tone and stiffness in the cervical region, which may have resulted from the position often adopted by young people when using smartphones [10,40].

In the study of Lo et al [33], the stiffness of the erector spinae muscle at L3–L4 in healthy people aged 38±12 years was 290.12±72.15 N/m (left side) and 301.89±85.04 N/m (right side), with no side-to-side differences identified using the t test for comparisons between participants with back pain and the control group [41]. These results indicate the symmetry of stiffness as the normative value.

Participants with unilateral chronic low back pain had more lumbar erector spinae stiffness on the painful side than on the non-painful side in a sitting position, but there was no significant difference in the prone position, and the intensity of pain among adults with chronic low back pain was not associated with muscle stiffness of the lumbar erector spinal muscles [12]. Furthermore, increased muscle tone and stiffness did not contribute to the occurrence of low back pain [42].

In our study, the participants were tested in a standing and then a sitting position, causing an increase in muscle tone and stiffness. This observation corresponds to the results of Feng et al [42]. In their study, lumbar erector spinae muscle stiffness was measured in healthy participants adopting different postures (static prone, sitting, and upright standing), with no significant differences between the left and right sides. The level of stiffness in different postures was as follows: sitting >static prone >upright standing [42]. These findings indicate that it is worthwhile exploring lumbar erector spinal muscle stiffness modulation in different postures to help prevent chronic low back pain [42]. In healthy adults, left-sided lumbar muscle stiffness measured at L4 in the prone position was 289.4 N/m, which was different in the standing (223–247 N/m) and sitting positions (321–299 N/m) [33].

CURVATURES OF THE SPINE:

Altering the position from standing to sitting caused significant changes in the angles of the anterior-posterior curvatures of the spine. The standing position was represented by most of the participants as a posture in which the α, β, and γ angles reached similar values, with the γ angle dominating, and the α angle having the lowest value. Participants were then asked to assume the sitting position with their upper limbs placed along the torso and their hip joints bent at a 90° angle. In the sitting position, there was a decrease in lumbar lordosis, compared with the standing position, while the thoracic angle reached a similar value in both the standing and sitting positions. The pelvis tilts backward in a sitting position [43], and a change in the position of the pelvis alters the anterior-posterior curvatures of the spine [44]. A reduction in lumbar lordosis, with a compensatory reduction in thoracic kyphosis, was the most dominant change. However, the lack of statistically significant differences in the γ angle in the standing and sitting positions results from the fact that the studied women tended to tilt their heads forward, probably as a mechanism aimed at maintaining physiological balance [45]. Other studies show that maintaining a sitting position for an extended period leads to a gradual increase in forward bending in the cervical spine [44].

The head tilts more forward in a sitting position, which is consistent with our research results, while an upright position causes greater tone in the thoracic spine erector muscle, reducing thoracic kyphosis [46]. In the sitting posture, which significantly increases thoracic kyphosis, the shoulder and scapula moves forward, and the head is tilted, a position often observed when working at a computer or using a telephone while sitting [10]. A natural sitting position in which both the lumbar section and the thoracolumbar junction increase kyphosis causes a C-shaped spine profile, which also causes a forward shift in the center of gravity [45]. Multiple variants of maintaining a sitting position provide further critical information with each position to a greater or lesser extent affecting the positioning of individual sections of the spine and changing the load on individual segments. Currently, this phenomenon is described as a factor that intensifies low back pain and causes sagittal imbalance, which affects people of all ages, especially students [47].

As previously mentioned, adopting the sitting position alters the shape of the anterior-posterior curvatures of the spine, as well as the mechanical properties of the erector spinal muscle. Therefore, it is crucial to precisely determine the position in which the tests are performed. This knowledge will enable and facilitate the selection of appropriate postural training that activates specific muscles, which will help overcome problems with balance and disability and reduce pain [30].

LIMITATIONS OF THE STUDY:

Some limitations must be pointed out. First, our observational study was a single-group type of study, which has its limitations due to the lack of control group. Therefore, we were careful to perform the exact same course of the study in all participants. The supporting factors for the choice of this type of study were the target group of healthy young women and the objective measurements conducted, which are characterized by high reliability and applicability in the context of habitual posture assessment. The photogrammetric method used to evaluate spinal angles is effective and safe, but it evaluates curvatures only in the sagittal plane. Although this method provides values similar to that of Cobb radiographic measurements [33], it should be emphasized that it is only a surface measurement based on determined points. Additionally, factors other than the erector muscle, such as superficial connective tissue, like thoracolumbar fascia and subcutaneous fat, can also affect the results when measuring the mechanical properties of soft tissues. Previous studies have found that the mechanical properties of soft tissues change with age [15], and there can also be differences between men and women and the specific body sites being examined [24]. We limited the effect of these factors by studying only young women, with BMI 21.70±2.26. Additionally, muscle activation was not considered and it was not controlled, since participants were asked to maintain habitual standing and sitting postures. Further investigation should focus on the tone and transverse stiffness of spinal muscle symmetry in different body positions.

Conclusions

Our findings indicated balanced spinal curvature and lower values of muscle tension and stiffness in the lumbar and thoracic regions in the standing position in young, healthy women. The sitting position decreased lumbosacral and thoracolumbar angles but increased muscle tone and stiffness in the lumbar and thoracic regions. The cervical region had the highest muscle tone and stiffness in the standing and sitting positions. The symmetry of muscle tone and stiffness in the cervical and thoracic regions in both positions was the normative value. These findings can be interpreted as adaptive physiological mechanisms in healthy young women and provide a reference for clinical studies of women.

References

1. Shumway-Cook A, Woollacott MH, Rachwani J, Santamaria V: Motor control: Translating research into clinical practice, 2007, Philadelphia, Lippincott Williams & Wilkins

2. Zadoń H, Nowakowska-Lipiec K, Michnik R, A sitting or standing position – which one exerts more loads on the musculoskeletal system of the lumbar spine? Comparative tests based on the methods of mathematical modelling: Acta Bioeng Biomech, 2021; 23(1); 113-20

3. Mrozkowiak M, Standardization of the diagnosis of body posture using photogrammetric methods MORA 4G HD: Fizjoterapia Polska, 2021; 1; 2-40

4. Porto F, Gurgel JL, Russomano T, Farinatti Pde T, Moiré topography: Characteristics and clinical application: Gait Posture, 2010; 32(3); 422-24

5. Barczyk-Pawelec K, Sipko T, Active self-correction of spinal posture in pain-free women in response to the command “straighten your back”: Women Health, 2017; 57(9); 1098-114

6. Żywień U, Barczyk-Pawelec K, Sipko T, Associated risk factors with low back pain in white-collar workers – a cross-sectional study: J Clin Med, 2022; 11(5); 1275

7. Korakakis V, O’Sullivan K, O’Sullivan PB, Physiotherapist perceptions of optimal sitting and standing posture: Musculoskelet Sci Pract, 2019; 39; 24-31

8. Lee ST, Moon J, Lee SH, Changes in activation of serratus anterior, trapezius and latissimus dorsi with slouched posture: Ann Rehabil Med, 2016; 40(2); 318-25

9. Guduru RKR, Domeika A, Domeikien A, Effect of rounded and hunched shoulder postures on myotonometric measurements of upper body muscles in sedentary workers: Appl Sci, 2022; 12; 12073333

10. Liang H, Yu S, Hao M, Effects of cervicothoracic postures on the stiffness of trapezius muscles: Med Biol Eng Comput, 2022; 60(10); 3009-17

11. Garrido-Castro JL, Aranda-Valera IC, Peña-Amaro J, Mechanical properties of lumbar and cervical paravertebral muscles in patients with axial spondyloarthritis: A case-control study: Diagnostics (Basel), 2021; 11(9); 1662

12. Li Y, Yu J, Zhang J, Zhang Z, Wang X, Quantifying the stiffness of lumbar erector spinae during different positions among participants with chronic low back pain: PLoS One, 2022; 17(6); e0270286

13. Villanueva A, Rabal-Pelay J, Berzosa C, Effect of a long exercise program in the reduction of musculoskeletal discomfort in office workers: Int J Environ Res Public Health, 2020; 17(23); 9042

14. Jo SH, Choi HJ, Cho HS, Effect of core balance training on muscle tone and balance ability in adult men and women: Int J Environ Res Public Health, 2022; 19(19); 12190

15. Wu Z, Wang Y, Ye Z, Effects of age and sex on properties of lumbar erector spinae in healthy people: preliminary results from a pilot study: Front Physiol, 2021; 12; 718068

16. Kim B, Yim J, Core stability and hip exercises improve physical function and activity in patients with non-specific low back pain: A randomized controlled trial: Tohoku J Exp Med, 2020; 251(3); 193-206

17. Mannion AF, Dumas GA, Cooper RG, Muscle fibre size and type distribution in thoracic and lumbar regions of erector spinae in healthy subjects without low back pain: Normal values and sex differences: J Anat, 1997; 190(Pt 4); 505-13

18. Huang R, Pan F, Kong C, Lu S, Age- and sex-dependent differences in the morphology and composition of paraspinal muscles between subjects with and without lumbar degenerative diseases: BMC Musculoskelet Disord, 2022; 23(1); 734

19. Muckelt PE, Warner MB, Cheliotis-James T, Protocol and reference values for minimal detectable change of MyotonPRO and ultrasound imaging measurements of muscle and subcutaneous tissue: Sci Rep, 2022; 12(1); 13654

20. Bartsch K, Brandl A, Weber P, Assessing reliability and validity of different stiffness measurement tools on a multi-layered phantom tissue model: Sci Rep, 2023; 13(1); 815

21. Chen G, Wu J, Chen G, Reliability of a portable device for quantifying tone and stiffness of quadriceps femoris and patellar tendon at different knee flexion angles: PLoS One, 2019; 14(7); e0220521

22. Agyapong-Badu S, Warner M, Samuel D, Stokes M, Measurement of ageing effects on muscle tone and mechanical properties of rectus femoris and biceps brachii in healthy males and females using a novel hand-held myometric device: Arch Gerontol Geriatr, 2016; 62; 59-67

23. Mencel J, Jaskólska A, Marusiak J, Effect of gender, muscle type and skinfold thickness on myometric parameters in young people: Peer J, 2021; 9; e12367

24. Usgu S, Ramazanoğlu E, Yakut Y, The relation of body mass index to muscular viscoelastic properties in normal and overweight individuals: Medicina (Kaunas), 2021; 57(10); 1022

25. Rodrigues-de-Souza DP, Casas-Castro A, Carmona-Pérez MC, Between-sexes differences in lumbopelvic muscle mechanical properties of non-climacteric adults: A cross-sectional design: Sci Rep, 2023; 13(1); 21612

26. Marfell-Jones M, Esparza-Ros F, Stewart A, de Ridder H, ISAK accreditation handbook: The International Society for the Advancement of Kinanthropometry, 2016

27. Labecka MK, Plandowska M, Moiré topography as a screening and diagnostic tool – a systematic review: PLoS One, 2021; 16(12); e0260858

28. Domagalska ME, Szopa AJ, Lembert DT, A descriptive analysis of abnormal postural patterns in children with hemiplegic cerebral palsy: Med Sci Monit, 2011; 17(2); CR110-16

29. O’Sullivan PB, Dankaerts W, Burnett AF, Effect of different upright sitting postures on spinal-pelvic curvature and trunk muscle activation in a pain-free population: Spine (Phila Pa 1976), 2006; 31(19); E707-12

30. Aroeira RM, Leal JS, de Melo Pertence AE, New method of scoliosis assessment: Preliminary results using computerized photogrammetry: Spine (Phila Pa 1976), 2011; 36(19); 1584-91

31. Muckelt PE, Warner MB, Cheliotis-James T, Protocol and reference values for minimal detectable change of MyotonPRO and ultrasound imaging measurements of muscle and subcutaneous tissue: Sci Rep, 2022; 12(1); 13654

32. Schoenrock B, Muckelt PE, Hastermann M, Muscle stiffness indicating mission crew health in space: Sci Rep, 2024; 14(1); 4196

33. Kelly JP, Koppenhaver SL, Michener LA, Characterization of tissue stiffness of the infraspinatus, erector spinae, and gastrocnemius muscle using ultrasound shear wave elastography and superficial mechanical deformation: J Electromyogr Kinesiol, 2018; 38; 73-80

34. Lohr C, Braumann KM, Reer R, Reliability of tensiomyography and myotonometry in detecting mechanical and contractile characteristics of the lumbar erector spinae in healthy volunteers: Eur J Appl Physiol, 2018; 118(7); 1349-59

35. Lo WLA, Yu Q, Mao Y, Lumbar muscles biomechanical characteristics in young people with chronic spinal pain: BMC Musculoskelet Disord, 2019; 20(1); 559

36. Cohen J: Statistical power analysis for the behavioral sciences, 1988, Routledge Hillsdale, NJ, Lawrence Erlbaum Associates, Publishers

37. Andersen TB, Essendrop M, Schibye B, Movement of the upper body and muscle activity patterns following a rapidly applied load: the influence of pre-load alterations: Eur J Appl Physiol, 2004; 91(4); 488-92

38. Sheeran L, Sparkes V, Caterson B, Spinal position sense and trunk muscle activity during sitting and standing in nonspecific chronic low back pain: Classification analysis: Spine (Phila Pa 1976), 2012; 37(8); E486-95

39. De Carvalho D, Greene R, Swab M, Godwin M, Does objectively measured prolonged standing for desk work result in lower ratings of perceived low back pain than sitting? A systematic review and meta-analysis: Work, 2020; 67(2); 431-40

40. Barczyk-Pawelec K, Sipko T, Spinal alignment in habitual standing position and while using smartphones in healthy young adults: Physiother Quart, 2024; 32(1); 105-10

41. Alcaraz-Clariana S, García-Luque L, Garrido-Castro JL, Influence of spinal movements associated with physical evaluation on muscle mechanical properties of the lumbar paraspinal in subjects with acute low back pain: Diagnostics (Basel), 2022; 12(2); 302

42. Li Y, Yu J, Zhang J, Zhang Z, Wang X, Quantifying the stiffness of lumbar erector spinae during different positions among participants with chronic low back pain: PLoS One, 2022; 17(6); e0270286

43. Kanawade V, Dorr LD, Wan Z, Predictability of acetabular component angular change with postural shift from standing to sitting position: J Bone Joint Surg Am, 2014; 96(12); 978-86

44. Jung SY, Choi BR, Three-dimensional change in the cervical spine in a cross-legged sitting position after a time lapse: J Phys Ther Sci, 2016; 28(5); 1657-59

45. Hey HWD, Teo AQA, Tan KA, How the spine differs in standing and in sitting-important considerations for correction of spinal deformity: Spine J, 2017; 17(6); 799-806

46. Lee CH, Lee S, Shin G, Reliability of forward head posture evaluation while sitting, standing, walking and running: Hum Mov Sci, 2017; 55; 81-86

47. Tsagkaris C, Widmer J, Wanivenhaus F, The sitting vs standing spine: N Am Spine Soc J, 2022; 9; 100108

In Press

Clinical Research  

Risk Factors for Bone Cement Displacement After Percutaneous Kyphoplasty in Osteoporotic Vertebral Fracture...

Med Sci Monit In Press; DOI: 10.12659/MSM.945884  

0:00

Clinical Research  

Adipose-Derived Mesenchymal Stem Cells from Arthritis Patients: Differential Modulation of CD4⁺ T Cell Acti...

Med Sci Monit In Press; DOI: 10.12659/MSM.945273  

0:00

Review article  

Surgical Advances in the Treatment of Acromioclavicular Joint Injury: A Comprehensive Review

Med Sci Monit In Press; DOI: 10.12659/MSM.942969  

Clinical Research  

Analysis of Mortality Causes and Locations in Veterans with ALS: A Decade Review

Med Sci Monit In Press; DOI: 10.12659/MSM.945816  

Most Viewed Current Articles

17 Jan 2024 : Review article   6,477,415

Vaccination Guidelines for Pregnant Women: Addressing COVID-19 and the Omicron Variant

DOI :10.12659/MSM.942799

Med Sci Monit 2024; 30:e942799

0:00

14 Dec 2022 : Clinical Research   1,909,282

Prevalence and Variability of Allergen-Specific Immunoglobulin E in Patients with Elevated Tryptase Levels

DOI :10.12659/MSM.937990

Med Sci Monit 2022; 28:e937990

0:00

16 May 2023 : Clinical Research   695,637

Electrophysiological Testing for an Auditory Processing Disorder and Reading Performance in 54 School Stude...

DOI :10.12659/MSM.940387

Med Sci Monit 2023; 29:e940387

0:00

07 Jan 2022 : Meta-Analysis   261,758

Efficacy and Safety of Light Therapy as a Home Treatment for Motor and Non-Motor Symptoms of Parkinson Dise...

DOI :10.12659/MSM.935074

Med Sci Monit 2022; 28:e935074

Your Privacy

We use cookies to ensure the functionality of our website, to personalize content and advertising, to provide social media features, and to analyze our traffic. If you allow us to do so, we also inform our social media, advertising and analysis partners about your use of our website, You can decise for yourself which categories you you want to deny or allow. Please note that based on your settings not all functionalities of the site are available. View our privacy policy.

Medical Science Monitor eISSN: 1643-3750
Medical Science Monitor eISSN: 1643-3750