INTRODUCTION:

Osteoporotic vertebral fractures (OVFs) are prevalent among adults with osteoporosis. The prevalence of OVFs in postmenopausal women was reported to be 15 to 35% and 10 to 30% in Western and Asian countries, respectively (Lau et al., 2000). These figures may be under reported as two-thirds adults with OVFs may remain asymptomatic (Lindsay et al., 2001) and, hence, undetected clinically (Delmas et al., 2005). The consequence of OVFs is debilitating, affecting morbidity, health-related quality of life, and mortality (Caliri, de Filippis, Bagnato, and Bagnato, 2007).

The causes of OVFs are multifactorial but can happen from even a very low impact force or back strain (Kim, Choi, Park, Lee, and Choi, 2015). Changes in back extensor muscle (BEM) function includes BEM strength, endurance, motor recruitment pattern, and its architectural changes are predisposing factors of OVFs or vice versa (Greig, Briggs, Bennell, and Hodges, 2014; Quirk and Hubley-Kozey, 2014; Sinaki et al., 2002; So et al., 2013).

Lower BEM attenuation (Anderson et al., 2013; Katzman, Miller-Martinez, Marshall, Lane, and Kado, 2014) and the decrease in muscle cross-sectional area (Kent-Braun, Ng, Young, 2000) may contribute to the decline of BEM strength. The fact that BEM strength is positively related to bone mineral density (BMD) is well established (Iki et al., 2002; So et al., 2013). The relationship of the BEM and BMD is site-specific as the muscle directly affects the bone to which it is attached; the relationship is also independent of age, body size, and vitamin D (Iki et al., 2002). Postmenopausal women with great BEM strength had a 10-fold lower risk of rapid bone loss compared with those with low BEM strength (Iki, Saito, Kajita, Nishino, and Kusaka, 2006).

Physiologically, age is related to high co-activation of the BEM and the changes in back kinematics during dynamic tasks (Kienbacher et al., 2015). Decline in BEM function may be due to one or a combination of many factors that may include age-related neuromuscular changes (Imagama et al., 2011; Power, Makrakos, Rice, and Vandervoort, 2013; Singh, Bailey, and Lee, 2013). Other factors included an alteration in thoracolumbar curvatures (Singh, Bailey, and Lee, 2010), as well as small fiber angles of BEMs (Singh, Bailey, and Lee, 2011), alteration of selective muscle atrophy of fast twitch fibres 1 (Macaluso and De Vito, 2003), and changes in BEM endurance (Champagne, Descarreaux, and Lafond, 2009; Quirk and Hubleykozey, 2014) and fat infiltration (Crawford, Volken, and Valentin, 2016; Valentin, Licka, and Elliot, 2015). The difference in BEM motor recruitment patterns (Parreira, de Oliveiraa, Amorima, Teixeiraa, and da Silvaa, 2014; Singh et al., 2011) in older adults may also suggest alterations in dynamic spinal stiffness and loading during a functional task that leads to the limitation in force-generation capacity (Champagne et al., 2009).

Back extensor muscle acts as the main contributor to balance external forces on the spine when supports from other intrinsic and external tissues declines with ages. Biomechanically, a decline in BEM function may exert large forces and increase spinal compressive loading on the spine (Reid and Fielding, 2012), thereby increasing the risk of OVFs. However, information regarding the influence of BEM on the osteoporosis spine, particularly OVFs, is unclear. The objective of this review was to summarize the evidence on the association between BEM function and OVFs among adults with osteoporosis.

METHODOLOGY:

An electronic search was conducted on PubMed, Medline/Ovid, Science Direct and Springerlink and reference lists were reviewed. Search terms included osteoporosis vertebral fracture concatenated with the following terms: (1) BEM strength, (2) BEM architecture/fat infiltration, (3) BEM endurance, and (4) BEM motor recruitment. Publications were included if they contained human studies, patients 65 years of age and above, original studies, and published in English language journals from 2000 to 2016. The exclusion criteria included animal studies and review /systematic review /meta-analysis.

RESULTS:

In total, 80 articles were researched through the search engines, and 8 were hand search from reference lists. After the removal of duplicates, titles and abstracts of the articles, a total of 32 potential articles were included in the present review. Twenty-two study designs were cross-sectional, seven prospective studies with duration to follow-up from 4 to 15 years, one within subject design, one case-control study, and two clinical trials. A minimum of 11 participants and a maximum of 1196 participants were included. Six studies included both genders, 24 studies were only women, and 2 studies were only men.

DISCUSSION:

The findings of the review confirmed that an association existed between OVFs and BEM strength, endurance, motor recruitment, thoracolumbar curvatures, and trunk muscle fat infiltration in older adults with OVFs.

There is no information about the direct cause-effect of BEM strength and osteoporosis comes to light. There was a decreased in BEM strength among postmenopausal women with osteoporosis occurred (Cunha-Henriques et al., 2011). In another study, postmenopausal women with greater BEM strength had a slow bone loss (Iki et al., 2002, 2006). Moreover, spinal compression fractures were reported to be reduced with long-term BEM strengthening exercises (Sinaki et al., 2002).

In a recent review, an association between BEM and osteoporosis was suggested as muscle-bone interaction (Mokhtarzadeh and Anderson, 2016). Muscle tissues produce local growth factors (IGF-1, and IGFBP-5) influencing bone in an anabolic fashion or regulating both bone and muscle centrally via genetic, growth hormones (e.g., GH/IGF-1, sex steroids, etc.) (Kaji, 2014). Bones and muscles were correlated via mechanical interactions (sarcopenia and osteoporosis) to a biochemical channel of communication through paracrine and endocrine signals (Isaacson and Brotto, 2014; Reginster, Beaudart, Buckinx, and Bruyère, 2016). The paracrine nature of the bone–muscle cross-talk acts at the muscle fiber attachment at the periosteal edges (Isaacson and Brotto, 2014). In addition, bone marrow mesenchymal stromal cells support osteogenesis and bone resorption in bone tissues (Kaji, 2014) and these may be some of the factors that regulate muscle mass (Sassoli, Pini, and Chellini, 2012).

In regard to a relationship between thoracolumbar curvature and OVFs, no direct relationship has been reported. However, evidence linking increased thoracic kyphosis and lumbar curvature to OVFs emerge. For example, postmenopausal women with osteoporotic had significantly higher thoracic kyphosis degree compared with the age-matched group (Cortet et al., 2002). Adults with OVFs had a higher magnitude of thoracic kyphosis (Greig et al., 2014; Kado et al., 2013; van der Jagt-Willems et al., 2015) and low back extensor muscles strength (Granito, Aveiro, and Renno, 2012; Granito, Aveiro, Renno, Oishi, and Driusso, 2014; Katzman et al., 2014). Great thoracic kyphosis was significantly associated with higher multi-segmental spinal loads and trunk muscle forces in upright stance (Briggs, Greig, Bennell, and Hodges, 2007). Thoracic hyperkyphosis with low BEM strength is a potential contributor to increased body sways, gait unsteadiness, and risk of falls in adults with osteoporosis (Regolin, and Carvalho, 2010; Sinaki, Brey, Hughes, Larson, and Kaufman, 2005). Thoracic hyperkyphotic posture is a risk factor for future fractures, independent of low BMD (Huang, Barrett-Connor, Greendale, and Kado, 2006; Roux, Fechtenbaum, and Kolta, 2010).

Increased thoracic kyphosis in adults with osteoporosis was likely to be related to compromised BEM strength rather than to bone loss (Mika, Unnithan, and Mika, 2005). Several studies corroborated that an increase BEMS can improve the spinal BMD and can decrease the incidence of spinal deformity in the osteoporotic spine (Bergström, Bergström, Kronhed, Karlsson, and Brinck, 2011; Iki et al., 2006). A 4-week specific BEM strengthening and gait program improved BEM strength, balance, gait, and risk of falls as well as reduced back pain in adults with osteoporosis and kyphosis (Sinaki et al., 2005). In addition, after 10-week of BEM strengthening and trunk control exercises, a reduction of 5% in thoracic kyphosis occurred (Sinaki, Brey, Hughes, Larson, and Kaufman, 2005).

With regards to the association between lumbar curvature and osteoporosis, the evidence is scarce. Nonetheless, older adults with high pelvic tilt and an increased lumbar lordosis had weak BEM (Hongo, Miyakoshi, Shimada, and Sinaki, 2012; Kim et al., 2015). Greater thoracic and lumbar kyphosis probably affects spinal inclination, resulting in sagittal imbalance and predisposing OVFs (Briggs et al., 2007; Greig, Bennell, Briggs, and Hodges, 2008; Kim et al., 2015). Biomechanically, an alteration in spinal alignment shortens the lever arm length in lumbar flexion, requiring larger extensor counter-moments (Brigg et al., 2007; Kim et al., 2015), thereby leading to high vertebral compression loading on BEM and susceptibility to back injury (Brigg et al., 2007; Kim et al., 2015). A review by Brigg, Greig, Wark, Fazalarri, and Bennell. (2004) confirmed that strong BEMs are vital to resist the flexion moment executed by gravity and any mass carried anteriorly to the spine. In addition, back mobility could preserve sagittal alignment (Imagama et al., 2011), indirectly reduce a risk of falls and fracture.

An indirect link exists between BEM architectural changes and osteoporosis. A correlation among BEM fat thickness, muscle area, and BMD of the femur was found in older adults with osteoporosis (Lee et al., 2015). In adults with OVFs, the decline in cross-sectional area (Kim, Chae, Kim, and Cha, 2013; Kim et al, 2015) and the increased fat infiltration of BEM (Katzman et al., 2012; Kim et al., 2013, 2015; So et al., 2013) were demonstrated. A significantly higher proportion BEM fat infiltration was observed in adults with lumbar degenerative kyphosis than in patients with low back pain (Kang, Shin, Kim, Lee, and Lee, 2007) and hyperkyphotic posture (Katzman et al., 2012). According to flexion-relaxation phenomenon, lumbar kyphosis may predispose to decline in signaling of BEM, leading to disuse and fat infiltration (Katzman et al., 2012).

Moreover, older adults with high fat infiltration and poor BEM function exhibit balanced impairment in following years predisposing to falls and fracture (Hick et al., 2005). Increases fat infiltration in the BEM increases the proportion of non-contractile tissues within muscle groups, leading to the reduction of the force generation capacity of the BEM (Hick et al., 2005). Spinal morphological changes may result in increased spinal loading, compression forces on the vertebral body and predispose to low bone mass, leading to the risk of fractures (So et al., 2013).

Our literature review confirmed the evidence linking BEM endurance muscle and motor recruitment to OVFs. For example, increased co-contraction of trunk flexor and extensor during forwarding arm movement was more prevalent in adults with OVFs compared with those without (Greig et al., 2014). This mechanism was also observed using electromyography in the adult with increased thoracic kyphosis (Greig et al., 2014). Higher co-contraction of the BEM in the older adults suggests that a compensatory mechanism minimizes vertebral loading time in women with OVFs (Briggs et al., 2007) and may increase compression spinal load and altered balance efficacy (Greig et al., 2014; Quirk and Hubley Kozey, 2014), predisposing the older adults to recurrent OVFs. In another study, the altered neuromuscular patterns of BEM were more prevalent in adults with OVFs than in those without (Bennell et al., 2010). Increased timed loaded standing times were correlated with increased BEM endurance (Shipp et al., 2000). Likewise, an improvement in the timed loaded standing test was gained by an exercise therapy (Bennell et al., 2010).

Longitudinal studies and randomized control trial on BEM function, including BEM strength, alteration of BEM architectural, endurance and motor recruitment, are lacking. A sound research comprehending the contributions of BEM function to OVFs remains a significant need. Moreover, an effective therapeutic intervention for optimizing BEM function in older adults with osteoporotic spine is warranted.

CONCLUSION:

Evidence of the fact that a relation exists between declined BEM function and increased risk of osteoporotic vertebral fractures, or vice versa, emerges. The BEMs and OVFs are linked to not only the BEM morphology and architectural and neuromuscular control but also the physiologically muscle-bone interaction. Consideration of these factors may be vital in establishing the prevention and management of osteoporotic vertebral fractures.

ACKNOWLEDGEMENTS:

This work is financially supported by a grant from Ministry of Higher Education through University Kebangsaan Malaysia (ERGS 1/2012/SKK/UKM/02/2). The authors also gratefully acknowledge the helpful comments and suggestions of the reviewers, which have improved the presentation.

REFERENCES:

1. Anderson, D. E., D'Agostino, J. M., Bruno, A. G., Demissie, S., Kiel, D. P., and Bouxsein, M. L. (2013). Variations of CT-based trunk muscle attenuation by age, sex and specific muscle. J Gerontol A Biol Sci Med Sci, 68, 317-323. doi: 10.1093/gerona/gls168.

2. Bennell, K. L., Matthews, B., Greig, A., Briggs, A., Kelly, A., Sherburn, M., Wark, J. (2010). Effects of an exercise and manual therapy program on physical impairments, function and quality of life in people with osteoporotic vertebral fracture: a randomized, single-blind controlled pilot trial. BMC Musculoskelet Disord, 11, 36. doi: 10.1186/1471-2474-11-36.

3. Bergström, I., Bergström, K., Kronhed, A. C. G., Karlsson, S., and Brinck, J. (2011). Back extensor training increases muscle strength in postmenopausal women with osteoporosis, kyphosis and vertebral fractures. Advances in Physiotherapy, 13, 110-117.

4. Briggs, A. M., Greig, A. M., Wark, J. D., Fazalarri, N. L., and Bennell, K. L. (2004). A review of anatomical and mechanical factors affecting vertebral body integrity. Int J Med Sci, 1, 170-180.

5. Briggs, A. M., Greig, A. M., Bennell, K. L., and Hodges, P. W. (2007). Paraspinal muscle control in people with osteoporotic vertebral fracture. Eur Spine J, 16, 1137-1144. doi:10.1007/s00586-006-0276-8.

6. Briggs, A. M., van Dieen, J. H., Wrigley, T. V., Greig, A, M., Phillips, B., Lo, S. K., and Bennell, K. L. (2007). Thoracic kyphosis affects spinal loads and trunk muscle force. Phys Ther, 87, 595-607.

7. Caliri, A., de Filippis, L., Bagnato, G. L., and Bagnato, G. F. (2007). Osteoporotic fractures: mortality and quality of Life. Panminerva Med, 49, 21-27.

8. Champagne, A., Descarreaux, M., and Lafond, D. (2009). Comparison between elderly and young males' lumbopelvic extensor muscle endurance assessed during a clinical isometric back extension test. J Manipulative Physiol Ther, 32, 521-526.

9. Cortet, B., Roches, E., Logier, R., Houvenagel, E., Gaydier-Souquières, G., François Puisieux, F., and Delcambre, B. (2002). Evaluation of spinal curvatures after a recent osteoporotic vertebral fracture. Joint Bone Spine, 69(2), 201-208.

10. Crawford, R. J., Volken, T., and Valentin, S. (2016). Rate of lumbar paravertebral muscle fat infiltration versus spinal degeneration in asymptomatic populations: an age aggregated cross-sectional simulation study. Scoliosis and Spinal Disorders, 11, 21. doi 10.1186/s13013-016-0080-0.

11. Cunha-Henriques, S., Costa-Paiva, L., Pinto-Neto, A. M., Fonsechi-Carvesan, G., Nanni, L., and Morais, S. S. (2011). Postmenopausal women with osteoporosis and musculoskeletal status: A comparative cross-sectional study. J Clin Med Res, 3, 168-176. doi: 10.4021/jocmr537w.

12. Delmas, L., van de Langerijt, L., Watts, N. B., Eastell, R., Genant, H., Grauer, A., and Cahall, D. L. (2005). Underdiagnosis of Vertebral Fractures Is a Worldwide Problem: The IMPACT Study. J Bone Miner Res, 20, 557-563.

13. Granito, R. N., Aveiro, M. C., and Renno, A. C. M. (2012) Comparison of thoracic kyphosis degree, trunk muscle strength and joint position sense among healthy and osteoporotic elderly women: A cross-sectional preliminary study. Archives of Gerontology and Geriatrics, 54, 199-202.

14. Granito, R. N., Aveiro, M. C., Renno, A. C. M., Oishi, J., and Driusso, P. (2014). Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women. Rev Bras Ortop, 49, 286-291.

15. Greig, A. M., Bennell, K. L., Briggs, A. M., and Hodges, P.W. (2008). Postural taping decreases thoracic kyphosis but does not influence trunk muscle electromyographic activity or balance in women with osteoporosis. Manual Therapy, 13, 249-257.

16. Greig, A. M., Briggs, A. M., Bennell, K. L., and Hodges, P. W. (2014). Trunk muscle activity is modified osteoporotic fracture and thoracic kyphosis with potential consequences. PLoS ONE, 9(10), e109515. doi: 10.1371/journal.pone.0109515.

17. Hick, G. E., Simonsick, E. M., Harris, T. B., Newman, A. B., Weiner, D. K., Nevitt, M. A., and Tylavsky, F. A. (2005). Cross-sectional associations between trunk muscle composition, back pain, and physical function in the Health, Aging and Body Composition Study. Journal of Gerontology, 60A, 882-887.

18. Hongo, M., Miyakoshi, N., Shimada, Y., and Sinaki, M. (2012). Association of spinal curve deformity and back extensor strength in elderly women with osteoporosis in Japan and the United States. Osteoporos Int, 23, 1029-1034. doi:10.1007/s00198-011-1624-z.

19. Huang, M. H., Barrett-Connor, E., Greendale, G. A., and Kado, D. M. (2006). Hyperkyphotic posture and risk of future osteoporotic fractures: The Rancho Bernardo Study. J Bone Miner Res, 21, 419-423. doi: 10.1359/JBMR.05120A.

20. Iki, M., Saito, Y., Dohi, Y., Kajita, E., Nishino, H., Yonemasu, K., and Kusaka, Y. (2002). Greater trunk muscle torque reduces post-menopausal bone loss at the spine independently of age, body size, and vitamin D receptor genotype in Japanese women. Calcif Tissue Int, 71, 300-307.

21. Iki, M., Saito, Y., Kajita, E., Nishino, H., and Kusaka, Y. (2006). Trunk muscle strength is a strong predictor of bone loss in postmenopausal women. Clin Orthop Relat Res, 443, 66-72.

22. Imagama, S., Matsuyama, Y., Hasegawa, Y., Sakai, Y., Ito, Z., Ishiguro, N., and Hamajima, N. (2011). Back muscle strength and spinal mobility are predictors of quality of life in middle-aged and elderly males. Eur Spine J, 20, 954-961. doi:10.1007/s00586-010-1606-4.

23. Isaacson, J., and Brotto, M. (2014). Physiology of Mechanotransduction: How Do Muscle and Bone "Talk" to One Another? Clin Rev Bone Miner Metab, 12, 77-85.

24. Kado, D. M., Huang, M. H., Karlamangla, A. S., Cawthon, P., Katzman, W., Hillier, T.A., . . . Cummings, S. R. (2013). Factors associated with kyphosis progression in older women: 15 years’ experience in the study of osteoporotic fractures. J Bone Miner Res, 28, 179–187.

25. Kaji, H. (2014). Interaction between muscle and bone. J Bone Metab, 21, 29–40.

26. Kang, C.H., Shin, M.J., Kim, S.M., Lee, S.H., and Lee, C.S. (2007). MRI of paraspinal muscles in lumbar degenerative kyphosis patients and control patients with chronic low back pain. Clin Radiol. 62, 479-486.

27. Katzman, W., Cawthon, P., Hicks, G. E., Vittinghoff, E., Shepherd, J., Cauley, J. A., Kado, D. M. (2012). Association of spinal muscle composition and prevalence of hyperkyphosis in healthy community-dwelling older men and women. J Gerontol A Biol Sci Med Sci, 67, 191-195. doi: 10.1093/gerona/glr160.

28. Katzman, W. B., Miller-Martinez, D., Marshall, L. M., Lane, N. E., and Kado, D. M. (2014). Kyphosis and paraspinal muscle composition in older men: a cross-sectional study for the osteoporotic fractures in men (MrOS) research group. BMC Musculoskeletal Disorders, 15, 19. doi: 10.1186/1471-2474-15-19.

29. Kent-Braun, J. A., Ng, A. V., and Young, K. (2000). Skeletal muscle contractile and non-contractile components in young and older women and men. J Appl Physiol, 88, 662-668.

30. Kienbacher, T., Paul, B., Habenicht, R., Starek, C., Wolf, M., Kollmitzer, J., Ebenbichler, G. (2015). Age and gender related neuromuscular changes in trunk flexion-extension. J Neuroeng Rehabil, 12, 3. Retrieved from http://www.jneuroengrehab.com/content/12/1/3.

31. Kim, J. Y., Chae, S. U., Kim, G. D., and Cha, M. S. (2013). Changes of paraspinal muscles in post-menopausal osteoporotic spinal compression fractures: Magnetic Resonance Imaging Study. J Bone Metab, 20, 75-81. http://dx. doi.org/10.11005/jbm.2013.20.2.75

32. Kim, D. H., Choi, D. H., Park, J. H., Lee, J. H., and Choi, Y. S. (2015). What is the effect of spinopelvic sagittal parameters and back muscles on osteoporotic vertebral Fracture? Asian Spine J, 9, 162-169. http://dx.doi.org/10.4184/asj.2015.9.2.162

33. Lau, E. M., Chan, Y. H., Chan, M., Woo, J., Griffith, J., and Chan, H. H. (2000). Vertebral deformity in Chinese men: prevalence, risk factors, bone mineral density, and body composition measurements. Calcif Tissue Int, 66, 47-52.

34. Lee, D. Y., Yang, J. H., Ki, C. H., Ko, M. S., Suk, K. S., Kim, H. S., Moon, S. H. (2015). Relationship between Bone Mineral Density and Spinal Muscle Area in Magnetic Resonance Imaging. J Bone Metab, 22, 197-204. doi: 10.11005/jbm.2015.22.4.197.

35. Lindsay, R., Silverman, S. L., Cooper, C., Hanley, D. A., Barton, I., Broy, S. B., Seeman, E. (2001). Risk of new vertebral fracture in the year following a fracture. JAMA, 285, 320 – 323.

36. Macaluso, A., and De Vito, D. (2004). Muscle strength, power and adaptations to resistance training in older people. Eur J Appl Physiol, 91, 450–472. doi 10.1007/s00421-003-0991-3.

37. Mika, A., Unnithan, V. B., and Mika, P. (2005). Differences in thoracic kyphosis and in back muscle strength in women with bone loss due to osteoporosis. Spine, 30, 241-246.

38. Mokhtarzadeh, H., and Anderson, D. E. (2016). The Role of Trunk Musculature in Osteoporotic Vertebral Fractures: Implications for Prediction, Prevention, and Management. Curr Osteoporos Rep, 14, 67-76. doi: 10.1007/s11914-016-0305-4.

39. Parreira, R. B., de Oliveiraa, M. R., Amorima, C. F., Teixeiraa, D. C., and da Silvaa, R. A. (2014). Older adults present better back endurance than young adults during a dynamic trunk extension exercise. J Back Musculoskelet Rehabil, 27, 153-159. doi:10.3233/BMR-13043.

40. Power, G. A., Makrakos, D. P., Rice, C. L., and Vandervoort, A. A. (2013). Enhanced force production in old age is not a far stretch: an investigation of residual force enhancement and muscle architecture. Physiol Rep, 1, e00004. doi: 10.1002/phy2.4.

41. Quirk, D.A., and Hubley-kozey, C.L. (2014). Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies. Hum Mov Sci Elsev BV, 38, 262–280.

42. Reginster, J. Y., Beaudart, C., Buckinx, F., and Bruyère, O. (2016). Osteoporosis and sarcopenia: two diseases or one? Curr Opin Clin Nutr Metab Care, 19, 31-36. doi: 10.1097/MCO.0000000000000230.

43. Regolin, F., and Carvalho, G. A. (2010). Relationship between thoracic kyphosis, bone mineral density, and postural control in elderly women. Rev Bras Fisioter, 14, 464-469.

44. Reid, K. F., and Fielding, R. A. (2012). Skeletal muscle power: A critical determinant of physical functioning in older adults. Exerc Sport Sci Rev, 40, 4-12.

45. Roux, C., Fechtenbaum, J., and Kolta, S. (2010). Prospective assessment of thoracic kyphosis in postmenopausal women with osteoporosis. J Bone Miner Res, 25, 362-368. doi: 10.1359/jbmr.090727.

46. Quirk, D.A., and Hubley-kozey, C.L. (2014). Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies. Hum Mov Sci Elsev BV, 38, 262–280.

47. Sassoli, C., Pini, A., and Chellini, F. (2012). Bone marrow mesenchymal stromal cells stimulate skeletal myoblast proliferation through the paracrine release of VEGF. PLoS One, 7, e37512. doi:10.1371/journal.pone.0037512.

48. Shipp, K. M., Purse, J. L., Gold, D. T., Pieper, C. F., Sloane, R., Schenkman, M., and Lyles, K. W. (2000). Timed loaded standing: a measure of combined trunk and arm endurance suitable for people with vertebral osteoporosis. Osteoporos Int, 11, 914-922.

49. Sinaki, M., Itoi, E., Wahner, H. W., Wollan, P., Gelzcer, R., Mullan, B. P., Hodgson, S. F. (2002). Stronger back muscles reduce the incidence of vertebral fractures: A prospective 10-year follow-up of postmenopausal women. Bone, 30, 836-841.

50. Sinaki, M., Brey, R. H., Hughes, C. A., Larson, D. R., and Kaufman, K. R. (2005). Balance disorder and increased risk of falls in osteoporosis and kyphosis: significance of kyphotic posture and muscle strength. Osteoporos Int, 16, 1004-1010.

51. Sinaki, M., Brey, R. H., Hughes, C. A., Larson, D. R., and Kaufman, K. R. (2005). Significant reduction in risk of falls and back pain in osteoporotic-kyphotic women through a spinal proprioceptive extension exercise dynamic (SPEED) program. Mayo Clin Proc, 80, 849-855.

52. Singh, D. K. A., Bailey, M., and Lee, R. Y. W. (2010). Biplanar measurement of thoracolumbar curvature in older adults using an electromagnetic tracking device. Arch Phys Med Rehabil, 91, 137-142.

53. Singh, D. K. A., Bailey, M., and Lee, R. Y. W. (2011). Ageing modifies the fiber angle and biomechanical function of the lumbar extensor muscles. Clin Biomech, 26, 543 -547.

54. Singh, D. K. A., Bailey, M., and Lee, R. Y. W. (2011). The strength and fatigue of lumbar extensor muscles in older adults. Muscle Nerve, 44, 74-79.

55. Singh, D. K. A., Bailey, M., and Lee, R. Y. W. (2013). Decline in lumbar extensor muscle strength in older adults: correlation with age, gender and spine morphology. BMC Musculoskelet Disord, 14, 215. Retrieved from http://www.biomedcentral.com/1471-2474/14/215.

56. So, K. Y., Kim, D. H., Choi, D. H., Kim, C. Y., Kim, J. S., and Choi, Y. S. (2013). The influence of fat infiltration on back extensor muscles on osteoporotic vertebral fracture. Asian Spine J, 7, 308-313.

57. Valentin, S., Licka, T., and Elliott, J. M. (2015). Age and side-related morphometric MRI evaluation of trunk muscles in people without back pain. Man Ther, 20, 90- 95.

58. van der Jagt-Willems, H. C., de Groot, M. H., van Campen, J. P., Lamoth, C. J., and Lems, W. F. (2015). Associations between vertebral fractures, increased thoracic kyphosis, a flexed posture and falls in older adults: a prospective cohort study. BMC Geriatr, 15, 34. doi: 10.1186/s12877-015-0018-z.

Received on 06.09.2017 Modified on 16.10.2017

Research J. Pharm. and Tech 2018; 11(11): 5130-5134.

DOI: 10.5958/0974-360X.2018.00936.8