Skip to main content

Trunk Skeletal Muscle Changes on CT with Long-Duration Spaceflight


Astronauts exposed to microgravity for extended time are susceptible to trunk muscle atrophy, which may compromise strength and function on mission and after return. This study investigates changes in trunk skeletal muscle size and composition using computed tomography (CT) and dual-energy X-ray absorptiometry (DXA) among 16 crewmembers (1 female, 15 male) on 4-6 month missions. Muscle cross-sectional area and muscle attenuation were measured using abdominal CT scans at pre-flight, post-flight return, 1 year post-flight, and 2–4 years post-flight. Longitudinal muscle changes were analyzed using mixed models. In six crewmembers, CT and DXA data were used to calculate subject height-normalized skeletal muscle indices. Changes in these indices were analyzed using paired t-tests and compared by imaging modality using Pearson correlations. Trunk muscle area decreased at post-flight return (− 4.7 ± 1.1%, p < 0.001) and recovered to pre-flight values at 1–4 years post-flight. Muscle attenuation changes were not significant. Skeletal muscle index from CT decreased (− 5.2 ± 1.0%, p = 0.004) while appendicular skeletal muscle index from DXA did not change significantly. In summary, trunk muscle atrophies with long-duration microgravity exposure but recovers to pre-flight values within 1–4 years. The CT measures highlight size decreases not detected with DXA, emphasizing the importance of advanced imaging modalities in assessing muscle health with spaceflight.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4


  1. Alkner, B. A., and P. A. Tesch. Knee extensor and plantar flexor muscle size and function following 90 days of bed rest with or without resistance exercise. Eur. J. Appl. Physiol. 93:294–305, 2004.

    PubMed  Google Scholar 

  2. Amini, B., S. P. Boyle, R. D. Boutin, and L. Lenchik. Approaches to assessment of muscle mass and myosteatosis on computed tomography: a systematic review. J. Gerontol. A Biol. Sci. Med. Sci. 74:1671–1678, 2019.

    PubMed  PubMed Central  Google Scholar 

  3. Anderson, D. E., J. M. D’Agostino, A. G. Bruno, S. Demissie, D. P. Kiel, and M. L. Bouxsein. Variations of CT-based trunk muscle attenuation by age, sex, and specific muscle. J. Gerontol. A Biol. Sci. Med. Sci. 68:317–323, 2012.

    PubMed  PubMed Central  Google Scholar 

  4. Aubrey, J., N. Esfandiari, V. E. Baracos, F. A. Buteau, J. Frenette, C. T. Putman, and V. C. Mazurak. Measurement of skeletal muscle radiation attenuation and basis of its biological variation. Acta Physiol. (Oxf.) 210:489–497, 2014.

    CAS  Google Scholar 

  5. Bailey, J. F., S. L. Miller, K. Khieu, C. W. O’Neill, R. M. Healey, D. G. Coughlin, J. V. Sayson, D. G. Chang, A. R. Hargens, and J. C. Lotz. From the international space station to the clinic: how prolonged unloading may disrupt lumbar spine stability. Spine J 18:7–14, 2018.

    PubMed  Google Scholar 

  6. Baumgartner, R. N., K. M. Koehler, D. Gallagher, L. Romero, S. B. Heymsfield, R. R. Ross, P. J. Garry, and R. D. Lindeman. Epidemiology of sarcopenia among the elderly in New Mexico. Am. J. Epidemiol. 147:755–763, 1998.

    CAS  PubMed  Google Scholar 

  7. Beavers, K. M., D. P. Beavers, D. K. Houston, T. B. Harris, T. F. Hue, A. Koster, A. B. Newman, E. M. Simonsick, S. A. Studenski, B. J. Nicklas, and S. B. Kritchevsky. Associations between body composition and gait-speed decline: results from the Health, Aging, and Body Composition study. Am. J. Clin. Nutr. 97:552–560, 2013.

    CAS  PubMed  PubMed Central  Google Scholar 

  8. Belavý, D. L., G. Armbrecht, C. A. Richardson, D. Felsenberg, and J. A. Hides. Muscle atrophy and changes in spinal morphology: is the lumbar spine vulnerable after prolonged bed-rest? Spine (Philr Pa 1976) 36:137–145, 2011.

    Google Scholar 

  9. Boutin, R. D., L. Yao, R. J. Canter, and L. Lenchik. Sarcopenia: current concepts and imaging implications. AJR Am. J. Roentgenol. 205:W255–266, 2015.

    PubMed  Google Scholar 

  10. Burkhart, K., B. Allaire, and M. L. Bouxsein. Negative effects of long-duration spaceflight on paraspinal muscle morphology. Spine (Phile Pa 1976) 44:879–886, 2019.

    Google Scholar 

  11. Chang, D. G., R. M. Healey, A. J. Snyder, J. V. Sayson, B. R. Macias, D. G. Coughlin, J. F. Bailey, S. E. Parazynski, J. C. Lotz, and A. R. Hargens. Lumbar spine paraspinal muscle and intervertebral disc height changes in astronauts after long-duration spaceflight on the international space station. Spine (Phila Pa 1976) 41:1917–1924, 2016.

    Google Scholar 

  12. Chen, L. K., L. K. Liu, J. Woo, P. Assantachai, T. W. Auyeung, K. S. Bahyah, M. Y. Chou, L. Y. Chen, P. S. Hsu, O. Krairit, J. S. Lee, W. J. Lee, Y. Lee, C. K. Liang, P. Limpawattana, C. S. Lin, L. N. Peng, S. Satake, T. Suzuki, C. W. Won, C. H. Wu, S. N. Wu, T. Zhang, P. Zeng, M. Akishita, and H. Arai. Sarcopenia in Asia: consensus report of the Asian Working Group for Sarcopenia. J. Am. Med. Dir. Assoc. 15:95–101, 2014.

    PubMed  Google Scholar 

  13. Cholewicki, J., M. M. Panjabi, and A. Khachatryan. Stabilizing function of trunk flexor-extensor muscles around a neutral spine posture. Spine (Philr Pa 1976) 22:2207–2212, 1997.

    CAS  Google Scholar 

  14. Crisco J. J. and M. M. Panjabi. Postural Biomechanical Stability and Gross Muscular Architecture in the Spine. In: Multiple Muscle Systems: Biomechanics and Movement Organization, edited by J. M. Winters and S. L. Y. Woo. New York, NY: Springer New York, 1990, pp. 438–450.

  15. Cruz-Jentoft A. J., G. Bahat, J. Bauer, Y. Boirie, O. Bruyère, T. Cederholm, C. Cooper, F. Landi, Y. Rolland, A. A. Sayer, S. M. Schneider, C. C. Sieber, E. Topinkova, M. Vandewoude, M. Visser, M. Zamboni, Writing Group for the European Working Group on Sarcopenia in Older People 2 and t. E. G. f. EWGSOP2. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing 48:16–31, 2018.

  16. Daly, L. E., C. M. Prado, and A. M. Ryan. A window beneath the skin: how computed tomography assessment of body composition can assist in the identification of hidden wasting conditions in oncology that profoundly impact outcomes. Proc. Nutr. Soc. 77:135–151, 2018.

    CAS  PubMed  Google Scholar 

  17. Dana Carpenter R., A. D. LeBlanc, H. Evans, J. D. Sibonga and T. F. Lang. Long-term changes in the density and structure of the human hip and spine after long-duration spaceflight. Acta Astronaut 67:71–81, 2010.

  18. Derstine, B. A., S. A. Holcombe, B. E. Ross, N. C. Wang, G. L. Su, and S. C. Wang. Skeletal muscle cutoff values for sarcopenia diagnosis using T10 to L5 measurements in a healthy US population. Sci. Rep. 8:11369, 2018.

    PubMed  PubMed Central  Google Scholar 

  19. Devane, K., D. Johnson, and F. S. Gayzik. Validation of a simplified human body model in relaxed and braced conditions in low-speed frontal sled tests. Traffic Inj Prev 20:832–837, 2019.

    PubMed  Google Scholar 

  20. Edgerton V. R. and R. R. Roy. Neuromuscular adaptations to actual and simulated spaceflight. Compr Physiol 721–763, 2010.

  21. Englund D. A., D. R. Kirn, A. Koochek, H. Zhu, T. G. Travison, K. F. Reid, Å. von Berens, M. Melin, T. Cederholm, T. Gustafsson and R. A. Fielding. Nutritional supplementation with physical activity improves muscle composition in mobility-limited older adults, the VIVE2 study: a randomized, double-blind, placebo-controlled trial. J. Gerontol. A Biol. Sci. Med. Sci. 73:95–101, 2017.

  22. Evetts, S. N., N. Caplan, D. Debuse, G. Lambrecht, V. Damann, N. Petersen, and J. Hides. Post space mission lumbo-pelvic neuromuscular reconditioning: a European perspective. Aviat. Space Environ. Med. 85:764–765, 2014.

    PubMed  Google Scholar 

  23. Gaewsky, J. P., D. A. Jones, X. Ye, B. Koya, K. P. McNamara, F. S. Gayzik, A. A. Weaver, J. B. Putnam, J. T. Somers, and J. D. Stitzel. Modeling human volunteers in multidirectional, uni-axial sled tests using a finite element human body model. Ann. Biomed. Eng. 47:487–511, 2019.

    PubMed  Google Scholar 

  24. Goodpaster, B. H., P. Chomentowski, B. K. Ward, A. Rossi, N. W. Glynn, M. J. Delmonico, S. B. Kritchevsky, M. Pahor, and A. B. Newman. Effects of physical activity on strength and skeletal muscle fat infiltration in older adults: a randomized controlled trial. J. Appl. Physiol. 105(1498–1503):2008, 1985.

    Google Scholar 

  25. Goodpaster, B. H., D. E. Kelley, F. L. Thaete, J. He, and R. Ross. Skeletal muscle attenuation determined by computed tomography is associated with skeletal muscle lipid content. J. Appl. Physiol. 89:104–110, 2000.

    CAS  PubMed  Google Scholar 

  26. Goodpaster B. H., S. W. Park, T. B. Harris, S. B. Kritchevsky, M. Nevitt, A. V. Schwartz, E. M. Simonsick, F. A. Tylavsky, M. Visser, and A. B. Newman. The loss of skeletal muscle strength, mass, and quality in older adults: the health, aging and body composition study. J. Gerontol. A Biol. Sci. Med. Sci. 61:1059−1064, 2006.

  27. Han A., S. L. Bokshan, S. E. Marcaccio, J. M. DePasse, and A. H. Daniels. Diagnostic criteria and clinical outcomes in sarcopenia research: a literature review. J. Clin. Med. 7: 2018.

  28. Hicks G. E., E. M. Simonsick, T. B. Harris, A. B. Newman, D. K. Weiner, M. A. Nevitt, and F. A. Tylavsky. Trunk muscle composition as a predictor of reduced functional capacity in the health, aging and body composition study: the moderating role of back pain. J. Gerontol. A Biol. Sci. Med. Sci. 60:1420–1424, 2005.

  29. Hides J. A., D. L. Belavý, W. Stanton, S. J. Wilson, J. Rittweger, D. Felsenberg, and C. A. Richardson. Magnetic resonance imaging assessment of trunk muscles during prolonged bed rest. Spine (Phila Pa 1976) 32:1687–1692, 2007.

  30. Hides, J. A., G. Lambrecht, C. A. Richardson, W. R. Stanton, G. Armbrecht, C. Pruett, V. Damann, D. Felsenberg, and D. L. Belavý. The effects of rehabilitation on the muscles of the trunk following prolonged bed rest. Eur. Spine J. 20:808–818, 2011.

    PubMed  Google Scholar 

  31. Hides J. A., G. Lambrecht, C. T. Sexton, C. Pruett, N. Petersen, P. Jaekel, A. Rosenberger, and G. Weerts. The effects of exposure to microgravity and reconditioning of the lumbar multifidus and anterolateral abdominal muscles; implications for people with LBP. Spine J. 2020.

  32. Janssen, I., R. N. Baumgartner, R. Ross, I. H. Rosenberg, and R. Roubenoff. Skeletal muscle cutpoints associated with elevated physical disability risk in older men and women. Am. J. Epidemiol. 159:413–421, 2004.

    PubMed  Google Scholar 

  33. Koo, T. K., and M. Y. Li. A guideline of selecting and reporting intraclass correlation coefficients for reliability research. J. Chiropr. Med. 15:155–163, 2016.

    PubMed  PubMed Central  Google Scholar 

  34. Lang, T., A. LeBlanc, H. Evans, Y. Lu, H. Genant, and A. Yu. Cortical and trabecular bone mineral loss from the spine and hip in long-duration spaceflight. J. Bone Miner. Res. 19:1006–1012, 2004.

    PubMed  Google Scholar 

  35. Larson-Meyer, D. E., S. R. Smith, L. K. Heilbronn, D. E. Kelley, E. Ravussin, and B. R. Newcomer. Muscle-associated triglyceride measured by computed tomography and magnetic resonance spectroscopy. Obesity (Silver Spring) 14:73–87, 2006.

    CAS  PubMed Central  Google Scholar 

  36. LeBlanc, A., C. Lin, L. Shackelford, V. Sinitsyn, H. Evans, O. Belichenko, B. Schenkman, I. Kozlovskaya, V. Oganov, A. Bakulin, T. Hedrick, and D. Feeback. Muscle volume, MRI relaxation times (T2), and body composition after spaceflight. J. Appl. Physiol. 89(2158–2164):2000, 1985.

    Google Scholar 

  37. McNamara, K. P., K. A. Greene, A. M. Moore, L. Lenchik, and A. A. Weaver. Lumbopelvic muscle changes following long-duration spaceflight. Front. Physiol. 10:627, 2019.

    PubMed  PubMed Central  Google Scholar 

  38. Melton L. J., 3rd, S. Khosla, C. S. Crowson, M. K. O’Connor, W. M. O’Fallon, and B. L. Riggs. Epidemiology of sarcopenia. J. Am. Geriatr. Soc. 48:625–630, 2000.

  39. Metter E. J., R. Conwit, J. Tobin, and J. L. Fozard. Age-associated loss of power and strength in the upper extremities in women and men. J. Gerontol. A Biol. Sci. Med. Sci. 52A:B267–B276, 1997.

  40. Mitsiopoulos, N., R. N. Baumgartner, S. B. Heymsfield, W. Lyons, D. Gallagher, and R. Ross. Cadaver validation of skeletal muscle measurement by magnetic resonance imaging and computerized tomography. J. Appl. Physiol. 85(115–122):1998, 1985.

    Google Scholar 

  41. Mourtzakis, M., C. M. Prado, J. R. Lieffers, T. Reiman, L. J. McCargar, and V. E. Baracos. A practical and precise approach to quantification of body composition in cancer patients using computed tomography images acquired during routine care. Appl. Physiol. Nutr. Metab. 33:997–1006, 2008.

    Google Scholar 

  42. Mulavara, A. P., B. T. Peters, C. A. Miller, I. S. Kofman, M. F. Reschke, L. C. Taylor, E. L. Lawrence, S. J. Wood, S. S. Laurie, S. M. C. Lee, R. E. Buxton, T. R. May-Phillips, M. B. Stenger, L. L. Ploutz-Snyder, J. W. Ryder, A. H. Feiveson, and J. J. Bloomberg. Physiological and functional alterations after spaceflight and bed rest. Med. Sci. Sports Exerc. 50:1961–1980, 2018.

    PubMed  PubMed Central  Google Scholar 

  43. Mulder, E. R., A. M. Horstman, D. F. Stegeman, A. de Haan, D. L. Belavý, T. Miokovic, G. Armbrecht, D. Felsenberg, and K. H. Gerrits. Influence of vibration resistance training on knee extensor and plantar flexor size, strength, and contractile speed characteristics after 60 days of bed rest. J. Appl. Physiol. 107(1789–1798):2009, 1985.

    Google Scholar 

  44. Pagano, A. F., T. Brioche, C. Arc-Chagnaud, R. Demangel, A. Chopard, and G. Py. Short-term disuse promotes fatty acid infiltration into skeletal muscle. J. Cachexia Sarcopenia Muscle 9:335–347, 2018.

    PubMed  Google Scholar 

  45. Ploutz-Snyder, L., J. Ryder, K. English, F. Haddad, and K. Baldwin. NASA evidence report: risk of impaired performance due to reduced muscle mass, strength, and endurance. Texas: Houston, 2015.

    Google Scholar 

  46. Poltronieri, T. S., N. S. de Paula, and G. V. Chaves. Assessing skeletal muscle radiodensity by computed tomography: an integrative review of the applied methodologies. Clin. Physiol. Funct. Imaging 40:207–223, 2020.

    PubMed  Google Scholar 

  47. Prado, C. M., J. R. Lieffers, L. J. McCargar, T. Reiman, M. B. Sawyer, L. Martin, and V. E. Baracos. Prevalence and clinical implications of sarcopenic obesity in patients with solid tumours of the respiratory and gastrointestinal tracts: a population-based study. Lancet Oncol. 9:629–635, 2008.

    Google Scholar 

  48. Ramachandran, V., S. Dalal, R. A. Scheuring, and J. A. Jones. Musculoskeletal Injuries in Astronauts: review of Pre-flight, In-flight, Post-flight, and Extravehicular Activity Injuries. Curr. Pathobiol. Rep. 6:149–158, 2018.

    CAS  Google Scholar 

  49. Scafoglieri A., S. Provyn, J. Wallace, O. Louis, J. Tresignie, I. Bautmans, J. De Mey, and J. P. Clarys. Whole body composition by Hologic QDR 4500/A DXA: system reliability versus user accuracy and precision. In: Applications and Experiences of Quality Control, edited by P. O. IvanovInTech, 2011, pp. 45–62.

  50. Shen W., M. Punyanitya, Z. Wang, D. Gallagher, M.-P. St.-Onge, J. Albu, S. B. Heymsfield, and S. Heshka. Total body skeletal muscle and adipose tissue volumes: estimation from a single abdominal cross-sectional image. J. Appl. Physiol. 97:2333–2338, 2004.

  51. Smith, M. G., M. Kelley, and M. Basner. A brief history of spaceflight from 1961 to 2020: an analysis of missions and astronaut demographics. Acta Astronaut 175:290–299, 2020.

    PubMed  Google Scholar 

  52. Study H. A. C. Longitudinal study of muscle strength, quality, and adipose tissue infiltration. Am. J. Clin. Nutr. 90:1579–1585, 2009.

    Google Scholar 

  53. Taaffe, D. R., T. R. Henwood, M. A. Nalls, D. G. Walker, T. F. Lang, and T. B. Harris. Alterations in muscle attenuation following detraining and retraining in resistance-trained older adults. Gerontology 55:217–223, 2009.

    PubMed  Google Scholar 

  54. Thornton W. E., W. G. Hoffler, and J. A. Rummel. Anthropometric Changes and Fluid Shifts. In: Biomedical results from Skylab, edited by R. S. Johnston and L. F. DietleinNational Aeronautics and Space Administration, 1977.

  55. Tuttle, L. J., D. R. Sinacore, and M. J. Mueller. Intermuscular adipose tissue is muscle specific and associated with poor functional performance. J. Aging Res. 2012:172957, 2012.

    PubMed  PubMed Central  Google Scholar 

  56. van der Werf A., J. A. E. Langius, M. A. E. de van der Schueren, S. A. Nurmohamed, K. van der Pant, S. Blauwhoff-Buskermolen, and N. J. Wierdsma. Percentiles for skeletal muscle index, area and radiation attenuation based on computed tomography imaging in a healthy Caucasian population. Eur. J. Clin. Nutr. 72:288–296, 2018.

  57. Visser M., B. H. Goodpaster, S. B. Kritchevsky, A. B. Newman, M. Nevitt, S. M. Rubin, E. M. Simonsick and T. B. Harris. Muscle mass, muscle strength, and muscle fat infiltration as predictors of incident mobility limitations in well-functioning older persons. J. Gerontol. A Biol. Sci. Med. Sci. 60:324–333, 2005.

  58. Williams, G. R., A. M. Deal, H. B. Muss, M. S. Weinberg, H. K. Sanoff, K. A. Nyrop, M. Pergolotti, and S. S. Shachar. Skeletal muscle measures and physical function in older adults with cancer: sarcopenia or myopenia? Oncotarget 8:33658–33665, 2017.

    PubMed  PubMed Central  Google Scholar 

  59. Ye, X., D. A. Jones, J. Gaewsky, B. Koya, K. McNamara, M. Saffarzadeh, J. Putnam, J. Somers, F. S. Gayzik, J. D. Stitzel, and A. Weaver. Lumbar spine response of computational finite element models in multidirectional spaceflight landing conditions. J. Biomech. Eng. 142:0510071–05100716, 2019.

    Google Scholar 

Download references


The authors thank Dr. Saroochi Agarwal, Meredith Rossi, and Charlie Warren from the NASA Lifetime Surveillance of Astronaut Health and Life Sciences Data Archive for preparing the retrospective dataset analyzed in this study. Funding was provided by the NASA Human Research Program (NNX16AP89G). Katelyn Greene is supported by a NIH/NIA Predoctoral Fellowship (F31 AG069414), and Dr. Ashley Weaver is supported by a NIH/NIA Career Development Award (K25 AG058804).

Conflict of interest

The authors have no conflicts of interest to disclose.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Ashley A. Weaver.

Additional information

Associate Editor Stefan M Duma oversaw the review of this article.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 73 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Greene, K.A., Withers, S.S., Lenchik, L. et al. Trunk Skeletal Muscle Changes on CT with Long-Duration Spaceflight. Ann Biomed Eng 49, 1257–1266 (2021).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Muscle atrophy
  • Computed tomography
  • Cross-sectional area
  • Muscle attenuation
  • Microgravity
  • Astronaut