https://orcid.org/0000-0002-2679-553X
Figures
Abstract
Background
Sitting for long periods of time and lack of physical activity in young adults can cause postural deterioration leading to rapid onset of fatigue and increase the risk of back pain. We were interested in whether there are gender differences in spinal curvature among university students with a predominantly sedentary lifestyle.
Methods
20 sedentary female (age 20 ± 0.73 years) and 39 sedentary male university students (age 20 ± 1.08 years) participated in this study. Their thoracic and lumbar curvatures were assessed while standing and sitting using a Spinal Mouse.
Results
In standing, 80.0% of the females and 69.2% of the males had a neutral position of the thoracic spine (33.25° and 35.33°, respectively). However, more males, 30.8%, than females, 10.0%, had hyperkyphosis (54.27° and 47.0°, respectively). Hypokyphosis was found in 10.0% of the females (18.50°) and none in the males. Similarly, 90.0% of the females and 97.4% of the males had neutral position of the lumbar spine (-33.11° and -29.76°, respectively). Increased hyperlordosis was found in 10.0% of the females and 2.6% of the males (-41.0° and -50.0°, respectively). Hypolordosis was not detected in either females or males. In sitting, on the other hand, 70.0% of the females and only 33.3% of the males had a neutral position of the thoracic spine (30.20° and 30.62°, respectively). Increased hyperkyphosis was found in 46.2% of the males (59.76°) and none of the females. 30.0% of the females and 23.1% of the males had light hypokyphosis (47.50° and 46.67°, respectively). Similarly, 70.0% of the females and only 38.5% of the males had a neutral position of the lumbar spine (7.0° and 6.6°, respectively). 35.9% of the males and only 5.0% of the females had a light hypokyphosis (16.14° and 16.0°, respectively). Slightly increased hyperkyphosis was identified in 25.6% of the males and 25.0% of the females (23.9° and 22.5°, respectively).
Conclusion
There are significant gender differences in spinal curvature. While in the thoracic spine it was to the detriment of the males when both standing and sitting, in the lumbar spine it is related to the females only when standing. It is therefore necessary to eliminate these spinal deviations in young adults induced by prolonged sitting during university courses by appropriate recovery modalities.
Citation: Cepková A, Zemková E, Šooš Ľ, Uvaček M, Muyor JM (2023) Sedentary lifestyle of university students is detrimental to the thoracic spine in men and to the lumbar spine in women. PLoS ONE 18(12): e0288553. https://doi.org/10.1371/journal.pone.0288553
Editor: Monika Błaszczyszyn, Opole University of Technology: Politechnika Opolska, POLAND
Received: November 4, 2022; Accepted: June 29, 2023; Published: December 5, 2023
Copyright: © 2023 Cepková et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper.
Funding: Funder: This work was supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Research and Development Agency under the contract. Name of the funded grant: “Split-Core Trainer Strengthening System for athletes and untrained Individuals with functional back pain”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Introduction
After starting their university studies, students acquire sedentary habits with a very low contribution of leisure activities [1, 2]. This causes reduced physical performance in young adults [3]. One consequence is lower back pain, which is associated with leisure-time physical inactivity [4]. This trend has been confirmed by a number of authors following the monitoring of university students`physical fitness o [5, 6]. Adults sit for eight hours daily and are on average active for 4 hours. This is a great disparity, which is reflected in their worsening physical fitness. The lack of physical activities and the predominance of a seated posture among students leads to an overloading of the same joint structures and the same muscle groups [7]. Motion passivity causes an insufficiency of the information coming into the central nervous system, which shares in the emergence of faulty motion stereotypes and muscle imbalance [8]. The main causes of muscle imbalance include hypokynesis, chronic loading above the limit set by muscle quality, asymmetric loading without sufficient compensation, and changes to the mobility stereotype, for example as a result of an injury or an illness [9].
Lack of movement and inappropriate physical activities, static overburdening, and unilateral loading affects posture [10]. Abnormal posture places strain on the ligaments and muscles, which may indirectly influence spinal curvature. Sitting for just 1 hour leads to increased spinal stiffness [11]. Thoracic mobility is reduced in individuals who spend >7 hours/day sitting and <150 min/week of physical activity [12]. There is a relationship between prolonged sitting and thoracic mobility, with >10° less mobility for sedentary than for physically active individuals [12]. Sitting also causes a reduction in lumbar lordosis and pelvic region, which could lead to a spinopelvic imbalance [13]. When sitting, the knees and hips are flexed, the pelvis rotates backward, and lumbar lordosis flattens [14]. A decrease of the trunk-thigh angle while sittting leads to flattening of the lumbar curve [15, 16]. Along with this, the lumbar intradiscal pressure increases [17, 18], which can contribute to the risk of developing back pain.
It is known that women are less active than men, thus they have significantly higher levels of sedentary behaviour [18]. However, the question remains as to whether there are gender differences in thoracic kyphosis and lumbar lordosis among young adults with a predominantly sedentary lifestyle.
Materials and methods
Participants
Two heterogeneous groups of randomly selected students of the mechanical engineering study program participated in the study: 39 males (age 20.0 ± 1.1 years, height 181.2 ± 6.9 cm, body mass 77.7 ± 12.3 kg, BMI 23.8 ± 1.6 kg/m2) and 20 females (age 20.0 ± 0.7 years, height 169.1 ± 4.2 cm, body mass 61.1 ± 5.8 kg, BMI 21.4 ± 1.4 kg/m2). The BMI of both groups is within the norm according to the WHO classification and does not affect their posture. A disparity between groups was due to a higher proportion of males (80%) than females (20%) of all university students.
Participants filled out the questionnaire that was related to basic demographic information, such as age, height, body mass, BMI, as well as to the inclusion criteria, including absence of pregnancy, absence of any regular sport, sedentary work for 8–10 hours a day, lack of history of spine surgery, absence of history of orthopedic disease in the past 5 years, no specific drug use for musculoskeletal or neurovascular disorders, no history of irreversible kyphosis or lordosis, and no history of scoliosis. They took part in compulsory optional physical education courses, once a week. While females participated in various types of aerobics, males played indoor soccer and floorball.
All participants were informed in advance about the course of the testing and verbally agreed to its conditions, with the participation of two witnesses, the investigators. The procedures followed were in accordance with the ethical standards for human experimentation outlined in the 1964 Declaration of Helsinki and its later amendments. The project was approved by the Ethics Committee of the Faculty of Physical Education and Sport of Comenius University in Bratislava (No. 4/2017).
Assessment of spinal curvature
Testing was performed by a member of our research team with long-term experience in spinal mouse measurement together with an assistant. One measurement took an average of 30 minutes. The measurements were carried out according to standard practices, ensuring compliance with hygienic, safe, and discreet conditions. The men were unclothed on the upper part of their bodies, while the women wore a swimsuit top and sports pants. Participants were assessed using the same methodology in two different positions, utilizing a spinal mouse. The first set of measurements aimed to evaluate the spine in an upright standing position, while the second set focused on an upright sitting position.
A computer based electro-mechanical Spinal Mouse device was used to assess posture (Idiag, Fehraltdorf, Switzerland). The Spinal Mouse is a valid and reliable device for measuring global thoracic and lumbar curvature compared to radiographic techniques [19–21], documented by an intraclass correlation coefficients (ICC) greater than 0.8 and a standard error of measurement (SEM) of less than 4º for all spinal parameters evaluated [20].
Measurements were performed at the sagittal level in a relaxed standing and sitting position, in a random order. All measurements were taken on the same day, in the same environment and under similar conditions. There was a 5-minute rest between each measurement. The examiner palpated the starting point C7 and the upper part of the anal fold (end point) and marked them on the skin. The examiner passed the Spinal Mouse along the central axis of the spine (or slightly paravertebral in particularly thin individuals) from C7 to the upper part of the anal fold (about S3). In each position, the values of the thoracic (T1-2 to T11-12) and lumbar vertebrae (T12-L1 to the sacrum) were recorded. In the lumbar curve, negative values corresponded to lumbar lordosis (concavity of the back).
Rating positions included standing, where the participant stood in a relaxed position with the head erect, hands next to the body, knees extended, feet shoulder width apart; and sitting, where the participant sat on the edge of the chair, knees bent to a 90° angle with legs apart, not touching the ground, head slightly bowed, hands on knees.
When evaluating a standing posture using the Spinal Mouse, the classification of the thoracic spine according to Mejia et al. [22] was used (Fig 1). Values between 20° and 45° were accepted as neutral thoracic kyphosis, values less than 20° were considered thoracic hypokyphosis, and values greater than 45° were considered thoracic hyperkyphosis. For the evaluation of the lumbar spine, a classification according to Tüzün et al. [23] was used (Fig 1). In a standing position, the lumbar curve values between 20° and 40° were taken as neutral, values less than 20° were considered as hypolordotic, and values greater than 40° were considered as hyperlordotic.
When evaluating a sitting posture with the Spinal Mouse, the classification of the thoracic part of the spine according to Martinez [24] was used (Fig 2). Values less than 41° were accepted as a neutral thoracic spine, values from 41° to 53° were considered as light thoracic hyperkyphosis, and values over 53° were considered as increased light hyperkyphosis. A classification according to Martinez [24] was also used for evaluation of the lumbar part of the spine (Fig 2). In a sitting position, lumbar curve values of less than 14° were considered neutral, values from 14° to 21° were considered as light lumbar hyperkyphosis, and values over 21° were considered as increased light lumbar hyperkyphosis.
In the sitting position, the spine has different curvature values than in the standing position, which can furthermore indicate the possible risks of LBP.
Statistical analysis
Data analyses were performed using the SPSS statistical program for Windows, version 18.0 (SPSS, Inc., Chicago, IL, USA). Descriptive statistics, including mean and standard deviations, were calculated for all variables. The hypotheses of normality and homogeneity of variance were analyzed using the Shapiro-Wilk test. An unpaired Student t-test was conducted to examine differences between females and males for all variables. The significance level was set at p < 0.05.
Results
In a standing position, 80.0% of the female students had a neutral position of the thoracic spine, with a mean value of 33.25°. 69.2% of the male students had a neutral position of the thoracic spine, with a mean value of 35.33°. Hypokyphosis, with a mean value of 18.50°, was found in 10.0% of the female students, and none in the male students. Hyperkyphosis, with a mean value of 54.27°, was found in 30.8% of the male students, compared to only 10.0% of the female students, with a mean value of 47.0° (Table 1).
Furthermore, 90.0% of the female students had a neutral position of the lumbar spine, with a mean value of -33.11°. Similarly, 97.4% of the male students had a neutral position of the lumbar spine, with a mean value of -29.76°. Hypolordosis was not detected in either the female or male students. Increased hyperlordosis, with a mean value of -41.0°, was found in 10.0% of the female students, and only in 2.6% of the male students, with a mean value of -50.0° (Table 1).
Between genders, significant differences in the thoracic part of the spine when standing were to the detriment of the male students, whilst in the lumbar part of the spine they were related to the detriment of the female students (Tables 2 and 3).
In sitting, 70.0% of the female students had the thoracic part of the spine in a neutral position, with a mean value of 30.20°. However, only 33.3% of the male students had the thoracic part of the spine in a neutral position, with a mean value of 30.62°. Here we found a significant difference in comparison with standing, where 69.23% of the students had an approximately equal value of 35.33°. 30.0% of the female students had light hypokyphosis, with a mean value of 47.50°. About equal values of 46.67° were found in 23.1% of the male students. 46.2% of the male students had indications of mild hyperkyphosis, with a mean value of 59.76°, whereas not a single case of increased hyperkyphosis was indentified among the female students (Table 4).
Furthermore, 70.0% of the female students and only 38.5% of the male students had a neutral position of the lumbar part of the spine, with a mean value of 7.0° and 6.6°, respectively. A light hypokyphosis, with a mean value of 16.14°, was found in 35.9% of the male students, and only in 5.0% of the female students, with a mean value of 16.0°. Slightly increased hyperkyphosis, with a mean value of 22.5°, was identified in 25.0% of the female students. Also 25.6% of the male students had slightly increased hyperkyphosis, with a mean value of 23.9° (Table 4).
Between the genders, there were significant differences in the thoracic part of the spine when sitting, to the detriment of the male students. However, no significant differences between genders were detected in the lumbar part of the spine while sitting (Tables 5 and 6).
Discussion
This study revealed gender-specific differences in spinal curvature. In the thoracic spine they are to the detriment of men when standing and sitting, whereas in the lumbar part to the detriment of women when standing. Young university students, just like office workers, spend most of their time in a sedentary manner at schools and during their leisure time [25–27]. This sedentary lifestyle puts them at a permanent risk of developing future musculoskeletal problems. Sedentary individuals experience higher fatigue compared to physically active individuals, primarily due to prolonged sitting [28], which can be a major cause of back pain. Based on these facts, it is most likely that regular engagement in sports among university students would lead to improved posture, i.e. a lower percentage of men would have chest hyperkyphosis, and fewer women would have lumbar hyperlordosis.
Lack of exercise leads to joint contracture, joint narrowing, and muscle stiffness [29, 30]. Additionally, it increases antagonistic co-contraction for stability, resulting in increased spinal compression [31]. Fatigue of back muscles, loss of muscle mass in young healthy individuals aggravates their ability to modify their posture strategy and may lead to a similar posture strategy to that seen in patients with recurrent low back pain as postural demands increase [32–36]. At present, a trend of increasing functional breakdowns of the locomotor system is apparent. Among students, this arises from adaptation to a daily mobility regime in which the same muscle groups are overused, leading to faulty mobility stereotypes [37, 38]. Research confirms the occurrence of sexual dimorphism of shortened and weakened muscles with a trend towards a greater occurrence of shortened muscles among the male population and weakened ones among the females [39–41]. Differences in posture between men and women have been confirmed by several researchers [42–44]. It is clear that it is very important to perform compensatory exercises, stretching, targeted strengthening exercises and exercises aimed at training the correct movement stereotypes to reduce the onset of neck and low back pain [45–48]. As a result, muscular activation is more effective and also muscular strength is increased. This is because thoracic joint mobilization or self-stretching exercises for the spine improve limited movements of the spine, recover facet joint sliding, and normalize the articular capsule, thereby decreasing kyphosis and enhancing the flexibility of thoracic extension [49–51]. The results of the proposed exercise are reflected in the overall posture.
In our research, a higher incidence of hyperlordosis in female than male students was found. A study by Jankowicz-Szymańska et al. [52] demonstrated that hyperlordosis is characteristic for young female students, while hypolordosis is characteristic for older women. In general, an increase in thoracic kyphosis causes lumbar hyperlordosis to maintain sagittal balance [53]. It can be said that the higher incidence of hyperkyphosis in men may be a clinical sign of the presence of osteoporosis and a potentially modifiable risk factor for adverse health consequences [54].
Furthermore, a higher incidence of hyperkyphosis in male than in female students was identified in our study. According to Almujel et al. [55], the correct curvature of the spine correlates significantly with the strength of the back muscles. The relationship between lordosis and kyphosis is more recognized in achieving sagittal alignment [56–60]. The emphasis on spinopelvic harmony was first outlined by Dubousset [61], whose idea of a "cone of balance" described a specific position of the spine in standing that allowed the body to remain in balance with minimal muscle mass. Changes in one part of the spine can lead to unintentional changes in another area [57]. The observed negative relationship suggests that when either thoracic or lumbar curvature increases due to less muscle load, regional bone mineral density decreases [62]. Factors such as age and gender could, therefore, affect loading through changes in lordosis. At the same age, body height (BH) and body weight (BW) female spines are subjected to greater loads due to the associated smaller arm muscules and passive joint contributions [63]. Increased kyphosis and thus lordosis cause many problems, including back pain [64] and standing imbalance [65–67]. Prolonged sitting increases muscle fatigue and promotes an increase in existing spinal curvature, which worsens posture and can be a possible cause of back pain for both men and women. As part of low back pain prevention, we recommend taking short regular breaks and performing compensatory exercises while sitting and standing. In addition to exercises for the spine as a whole, attention should be paid to those able to eliminate thoracic kyphosis in male students and lumbar lordosis in female students.
The main limitation of this study is the small sample of female students, which is due to the overall low number of female students at the university of technology and the subjectivity of the assessment procedure. For this reason, these findings cannot be generalized to the broader community based on this study alone.
Conclusions
There are significant gender differences in spinal curvature. While in the thoracic spine it was to the detriment of the males when both standing and sitting, in the lumbar spine it is related to the females only when standing. More specifically, the majority of the females and males had a neutral position of the thoracic spine (80.0% vs 69.2%) and the lumbar spine (90.0% vs 97.4%) while standing. However, more males than females had hyperkyphosis (30.8% vs 10.0%) and hypokyphosis (10.0% vs 0%), whilst hyperlordosis was found more in females than males (10.0% and 2.6%). On the other hand, more females than males had a neutral position of the thoracic spine (70.0% vs 33.3%) and the lumbar spine (70.0% vs 38.5%) while sitting. Thoracic hyperkyphosis was found only in males (46.2%), and hypokyphosis slightly more in females than males (30.0% vs 23.1%). More males than females showed lumbar hypokyphosis (35.9% vs 5.0%), whereas the occurrence of hyperkyphosis was comparable (25.6% vs 25.0%). These findings indicate that the sedentary lifestyle of university students is detrimental to the thoracic spine in men and to the lumbar spine in women. Therefore, it is necessary to eliminate these spinal deviations in young adults (thoracic kyphosis in males and lumbar lordosis in females) induced by prolonged sitting during university courses by appropriate recovery modalities.
References
- 1.
Liba J, Buková A. Pohyb a zdravie. Košice: Equilibria, s.r.o.; 2008.
- 2. Cepková A, Kyselovičová O, Honz O et al. Somatic changes of university students in BMI and WHR. Acta Facultatis Educationis Physicae Universitatis Comenianae. 2016; 56(1): 30–41.
- 3. Morrell JS, Cook SB, Carey GB. Cardiovascular fitness, activity, and metabolic syndrome among college men and women. Metabolic Syndrome and Related Disorders. 2013; 11(5): 370–376. pmid:23809000
- 4. Yang H, Haldeman S. Behavior-related factors associated with low back pain in the US adult population. Spine. 2018;43(1): 28–34. pmid:27128393
- 5. Martens MP et al. The short-term efficacy of a brief motivational intervention designed to increase physical activity among college students. Journal of Physical Activity and Health. 2012; 9(4): 525–532. pmid:21934167
- 6. Varela-Mato V et al. Lifestyle and health among Spanish university students: differences by gender and academic discipline. International Journal of Environmental Research and Public Health. 2012; 9(8): 2728–2741. pmid:23066393
- 7.
Zvonař M et al. Antropomotorika pro magisterský program tělesná výchova a sport. Brno: Muni PRESS; 2011.
- 8. Molnárová M. Postura—význam, diagnostika a poruchy. Rehabilitácia. 2009; 46(4): 195–205.
- 9.
Lewit K. Manipulační léčba v myoskeletální medicíně. Sdělovací technika, spol. s.r.o.; 2003.
- 10. Hansraj KK. Assessment of stressed in the cervical spine caused by posture and the position of the head. Surgery Technology. 2014; 25: 277–279. pmid:25393825
- 11. Beach TA, Parkinson RJ, Stothart JP, et al. Effects of prolonged sitting on the passive flexion stiffness of the in vivo lumbar spine. Spine J. 2005; 5: 145–154. pmid:15749614
- 12. Heneghan NR, Baker G, Thomas K, Falla D, Rushton A. What is the effect of prolonged sitting and physical activity on thoracic spine mobility? An observational study of young adults in a UK university setting. BMJ Open. 2018; 8(5): e019371. pmid:29730619
- 13. Cho Y, Park SY, Park JH, Kim TK, Jung TW, Lee HM. The effect of standing and different sitting positions on lumbar lordosis: Radiographic study of 30 healthy volunteers. Asian Spine J. 2015; 9(5): 762–769. pmid:26435796
- 14. Lengsfeld M, Frank A, van Deursen DL, Griss P. Lumbar spine curvature during office chair sitting. Med Eng Phys. 2000; 22: 665–669. pmid:11259935
- 15. Keegan JJ. Alterations of the lumbar curve related to posture and seating. J Bone Joint Surg Am. 1953; 35: 589–603. pmid:13069548
- 16. Andersson BJ, Ortengren R, Nachemson AL, Elfstrom G, Broman H. The sitting posture: an electromyographic and discometric study. Orthop Clin North Am. 1975; 6: 105–120. pmid:1113963
- 17. Nachemson A, Morris JM. In vivo measurements of intradiscal pressure: discometry, a method for the determination of pressure in the lower lumbar discs. J Bone Joint Surg Am. 1964; 46: 1077–1092. pmid:14193834
- 18. Editorial. Time to tackle the physical activity gender gap. Lancet Public Health. 2019; 4(8): e360. pmid:31345750
- 19. Guermazi M, Ghroubi S, Kassis M, Jaziri O, Keskes H, Kessomtini W, et al. Validity and reliability of Spinal Mouse® to assess lumbar flexion. Ann Readapt Med Phys. 2006; 49: 172–177. pmid:16630669
- 20. Mannion AF, Knecht K, Balaban G, Dvorak J, Grob D. A new skin-surface device for measuring the curvature and global and segmental ranges of motion of the spine: reliability of measurements and comparison with data reviewed from the literature. Eur Spine J. 2004; 13: 122–136. pmid:14661104
- 21. Post RB, Leferink VJ. Spinal mobility: sagittal range of motion measured with the Spinal Mouse, a new non-invasive device. Arch Orthop Trauma Sur. 2004; 124: 187–192. pmid:14968367
- 22. Mejia EA, Hennrikus WL, Schwend RM, Emans JB. A prospective evaluation of idiopathic left thoracic scoliosis with MRI. Journal of Pediatric Orthopedics. 1996; 16: 354–358. pmid:8728637
- 23. Tüzün C, Yorulmaz I, Cindaş A, Vatan S. Low back pain and posture. Clin Rheumatol. 1999; 18: 308–312. pmid:10468171
- 24.
Martínez P. Disposición del raquis en el plano sagital y extensibilidad isquiosural en Gimnasia Rítmica Deportiva. Murcia: Tesis Doctoral, 2004.
- 25. Collins JD, O’Sullivan LW. Musculoskeletal disorder prevalence and psychosocialrisk exposures by age and gender in a cohort of office based employees in two academic institutions. International Journal of Industrial Ergonomic, 2015; 46: 85–97.
- 26. Hadgraft NT, Lynch BM, Clark BK, Healy GN, Owen N, Dunstan DW. Excessive sitting at work and at home: correlates of occupational sitting and TV viewing timein working adults. BMC Public Health. 2015; 15: 899. pmid:26374514
- 27. Hanna F, Daas RN. The relationship between sedentary behavior, back pain, and psychoso-cial correlates among university employees. Frontiers in Public Healt, 2019; 7: 80. pmid:31024881
- 28. Engberg I, Segerstedt J, Waller G, Wennberg P, Eliasson M. Fatigue in the generalpopulation associations to age, sex, socioeconomic status, physical activity, sitting time and self-rated health: The Northern Sweden MONICA Study 2014. BMC PublicHealth. 2017; 17(1): 654. pmid:28806984
- 29. Moriyama H. The effects of exercise on joints. Clinical Calcium. 2017; 27(1): 87–94. pmid:28017950.
- 30. Herzog W, Powers K, Johnston K, Duvall M. A new paradigm for muscle contraction. Frontiers in Physiology. 2015; 6: 174. pmid:26113821
- 31. Granata KP, Slota GP, Wilson SE. Influence of fatigue in neuromuscular control of spinal stability. Human Factors, 2004; 46(1): 81–91. pmid:15151156
- 32. Johanson E. et al. The effect of acute back muscle fatigue on postural control strategy in people withand without recurrent low back pain. European Spine Journal. 2011; 20(12): 2152–2159. pmid:21533851
- 33. Paddon-Jones D et al. Essential amino acid and carbohydrate supplementation ame-liorates muscle protein loss in humans during 28 days bedrest. J Clin Endocrinol Metab. 2004; 89(9): 4351–4358. pmid:15356032
- 34. Claeys K, Dankaerts W, Janssens L, Pijnenburg M, Goossens N, Brumagne S. Young individuals with a more ankle-steered proprioceptive control strategy maydevelop mild non-specific low back pain. Journal of Electromyography and Kinesiology. 2015; 25 (2): 329–338. pmid:25467548
- 35.
Kendall FP, Mc Creary EK, Provance PG, Rodgers MM, Romani WA. Muscles: testing and function with posture and pain. Baltimore: Lippincott Williams & Wilkins; 2005.
- 36. Šteňo J, Džubera A, Schnorrer M,. Kordoš J, Haruštiak S. Chirurgické liečenie herniovaných diskov hrudnej chrbtice. Česko-Slov Neurol Neurochir. 2001; 64(1): 57–61.
- 37. Šteňo J, Maláček M, Illéš R, Džubera A, Šurkala J, Trnovec S, et al. Minimálne invazívne výkony pri herniách diskov lumbosakrálnej chrbtice. Acta Spondylog. 2002; 1(2): 113–116.
- 38. Riegerová J. Hodnocení posturálních funkcí a pohybových stereotypú u dětské populace nesportovcú a dětí zabývajících se rúznymi druhy sportovní činnosti. Česká kinantropologie. 2004; 54: 169–171.
- 39. Kanásová J, Czaková N, Divinec L, Veis A, Solvesterová M. Impact of balance exercises on the elimination of func-tional muscular disorders in volleyball players. Physical Activity Review. 2019; 7: 152–159.
- 40.
Bartík P. Úroveň posturálnych svalov žiakov 5. a 9. ročníkov na vybranej základnej škole. Zborník Súčasnosť a perspektívy telovýchovného procesu na školách. 2006; 26–46.
- 41. Bakalár I, Šimonek J, Kanásová J, Krčmárová B, Krčmár M. Multiple athletic performances, maturation, and Functional Movement Screen total and individual scores across different age categories in young soccer players. Journal of Exercise Rehabilitation. 2020;16(5): 432–441. pmid:33178645
- 42. Chen YL, Chan YC, Zhang LP. Postural variabilities associated with the most comfortable sitting postures: A preliminary study. Healthcare (Basel). 2021; 9(12): 1685. pmid:34946411
- 43. Wigaeus Tornqvist E, Hagberg M, Hagman M, Hansson Risberg E, Toomingas A. The influence of working conditions and individual factors on the incidence of neck and upper limb symptoms among professional computer users. Int Arch Occup Env Health, 2009; 82: 689–702. pmid:19205721
- 44. Norman K, Floderus B, Hagman M, Wigaeus Tornqvist E, Toomingas A. Musculoskeletal symptoms in relation to work exposures at call centre companies in Sweden. Work. 2008; 30 (2): 201–214. pmid:18413936.
- 45. Karlqvist L, Tornqvist EW, Hagberg M, Hagman M, Toomingas A. Self-reported working conditions of VDU operators and associations with musculoskeletal symptoms: a cross-sectional study focussing on gender differences. Int J Ind Ergon. 2002; 30: 277–294.
- 46. Waongenngarm P, van der Beek AJ, Akkarakittichoke N, Janwantanakul P. Effects of an active break and postural shift intervention on preventing neck and low-back pain among high-risk office workers: a 3-arm cluster-randomized controlled trial. Scand J Work Environ Health. 2021; 47(4): 306–317. pmid:33906239
- 47. Kim E, Lee H. The effects of deep abdominal muscle strengthening exercises on respiratory function and lumbar stability. J Phys Ther Sci. 2013 Jun; 25(6):663–5. Epub 2013 Jul 23. pmid:24259823.
- 48. Choi H-S, Lee S-Y. Comparison of multifidus and external oblique abdominis activity in standing position according to the contraction patterns of the gluteus maximus [Internet]., Physical Therapy Rehabilitation Science. 2016; Vol. 5: 40–6. http://dx.doi.org/10.14474/ptrs.2016.5.1.40
- 49.
Kaltenborn F. Manual mobilization of the extremity joint: basic evaluation and treatment techniques. Oslo: Olaf norisbok handel. 2014; pp 23–48.
- 50. Kim HS, Lee KH, Bae SS. The effects of trunk stabilization exercise on the back pain disability index in chronic low back pain. Korean Soc Phys Med. 2008; 23: 193–202.
- 51. Hwangbo PN, Hwangbo G, Park J. et al. The effects of thoracic joint mo-bilization and self-stretching exercise on pulmonary functions of patients with chronic neck pain. J Phys Ther Sci. 2014; 26: 1783–1786. pmid:25435700
- 52. Jankowicz-Szymańska A, Bibro M, Wódka K, Smoła E. The influence of age on the body posture of women. Health Promotion & Physical Activity. 2018; 1: 1–6.
- 53. Pazhoohi F, Garza R, Kingstone A. Sexual receptivity signal of lordosis posture and intra-sexual competition in women. Sexes. 2022; 3: 59–67.
- 54. Endo K, Suzuki H, Nishimura H, Tanaka H, Shishido T, Yamamoto K. Characteristics of sagittal spino-pelvic alignment in Japanese young adults. Asian Spine Journal. 2014; 8(5): 599–604. pmid:25346812
- 55. Almujel K et al. Causes and management of hyperkyphosis. Journal of Pharmaceutical Research International. 2021; 1–8.
- 56. Vialle R, Levassor N, Rillardon L, Templier A, Skalli W, Guigui P. Radiographic analysis of the sagittal alignment and balance of the spine in asymptomatic subjects. J Bone Joint Surg Am. 2005; 87: 260–267. pmid:15687145
- 57. Diebo BG, Varghese JJ, Lafage R, Schwab FJ, Lafage V. Sagittal alignment of the spine: what do you need to know? Clin Neurol Neurosurg. 2015; 139: 295–301. pmid:26562194
- 58. Schwab FJ, Blondel B, Bess B, et al. Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine (Phila. Pa. 1976). 2013; 38: E803–E812. pmid:23722572
- 59. Moal B, Schwab F, Ames CP, et al. Radiographic outcomes of adult spinal deformity correction: a critical analysis of variability and failures across deformity patterns. Spine Deform. 2014; 2: 219–225. pmid:27927422
- 60. Schwab FJ, Diebo BG, et al. Fine-tuned surgical planning in adult spinal deformity: determining the lumbar lordosis necessary by accounting for both thoracic kyphosis and pelvic incidence. Spine J. 2014; 14(11 suppl): S73.
- 61.
Dubousset J. Three-dimensional analysis of the scoliotic deformity. In: Weinstein SL, ed. The Pediatric Spine: Principles and Practices. New York, NY: Raven Press; 1994: 479–496.
- 62. Pavlovic A, Nichols DL, Sanborn CF, Dimarco NM. Relationship of thoracic kyphosis and lumbar lordosis to bone mineral density in women. Osteoporos Int. 2013; 24(8): 2269–2273. pmid:23400251
- 63. Ghezelbash F, Shirazi-Adl A, Arjmand N, El-Ouaaid Z, Plamondon A, Meakin JR. Effects of sex, age, body height and body weight on spinal loads: Sensitivity analyses in a subject-specific trunk musculoskeletal model. Journal of Biomechanics. 2016; 49(14): 3492–3501. pmid:27712883
- 64. Libby D. Acute respiratory failure in sco-liosis or kyphosis. Am J Med. 1982; 4: 532–538.
- 65.
Kendall FP, McCreary EK, Provance PG, Rodgers MM, Romani WA. Muscles: testing and function with posture and pain. Baltimore: Lippincott Williams & Wilkins; 2005.
- 66. Claus AP, Hides JA, Moseley GL, Hodges PW. Thoracic and lumbar posture behaviour in sitting tasks and standing: Progressing the biomechanics from observations to measurements. Applied Ergonomics. 2016; 53: 161–168. pmid:26476893
- 67. Vialle R, Levassor N, Rillardon L, Templier A, Skalli W, Guigui P. Radiographic analysis of the sagittal alignment and balance of the spine in asymptomatic subjects. J. Bone Jt. Surg. Am. 2005; 87: 260–267. pmid:15687145