Osteoporosis International

, Volume 3, Issue 1, pp 8–12 | Cite as

Muscle strength in Osteoporotic versus normal women

  • M. Sinaki
  • S. Khosla
  • P. J. Limburg
  • J. W. Rogers
  • P. A. Murtaugh
Original Article


Strong back muscles contribute to good posture and skeletal support. Osteoporosis, being a metabolic bone disease, should not affect muscle strength. In this study we were interested in comparing the back extensor strength (BES) of osteoporotic and normal women. Fifty-five women ages 40–85 years who had a documented diagnosis of osteoporosis and were referred for initiation of proper exercise programs were included in our study after meeting the inclusion criteria. They all had evaluation of their posture, back and upper extremity strength, and physical activity score through our Rehabilitation of Osteoporosis Program -Exercise (ROPE). In addition, to avoid the interference of pain on application of maximal effort, we did not include subjects with acute back pain or those who experienced back pain with maximal effort during the testing trial. BES for osteoporotic women ranged from 16 to 65 lb (mean ± SD, 36.5±15.5) for ages 40–59 years, 9 to 55 lb (mean ± SD, 29.9±10.6) for ages 60–69 years, 6 to 52 lb (mean ± SD, 24.3±10.2) for ages 70–79 years, and 17 to 27 lb (mean ± SD, 21.2±4.2) for ages 80 years or older. Comparison of these data with the BES of 25 normal women, with statistical adjustment for age, demonstrated that the osteoporotic women had significantly lower BES than the normal women. A longitudinal study of a larger group of women would be of great interest for clarifying whether the weakness of back extensors precedes and, indeed, contributes to compression fractures of the spine.


Back extensor strength Osteoporosis Physical activity Posture 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Saville PD. The syndrome of spinal osteoporosis. Clin Endocrinol Metab 1973;2:177–85.Google Scholar
  2. 2.
    Sinaki M, McPhee MC, Hodgson SF, Merritt JM, Offord KP. Relationship between bone mineral density of spine and strength of back extensors in healthy postmenopausal women. Mayo Clin Proc 1986;61:116–22.Google Scholar
  3. 3.
    Sinaki M, Offord KP. Physical activity in postmenopausal women: effect of back muscle strength and bone mineral density of the spine. Arch Phys Med Rehabil 1988;69:277–80.Google Scholar
  4. 4.
    Limburg PJ, Sinaki M, Rogers JW, Caskey PE, Pierskalla BK. A useful technique for measurement of back strength in osteoporotic and elderly patients. Mayo Clin Proc 1991;66:39–44.Google Scholar
  5. 5.
    Chaffin DB. Ergonomics guide for the assessment of human static strength. Am Ind Hyg Assoc J 1975;36:505–11.Google Scholar
  6. 6.
    Nachemson A, Lindh M. Measurement of abdominal and back muscle strength with and without low back pain. Scand J Rehabil Med 1969;1:60–5.Google Scholar
  7. 7.
    Beasley WC. Quantitative muscle testing: principles and applications to research and clinical services. Arch Phys Med Rehabil 1961;42: 398–425.Google Scholar
  8. 8.
    Beasley WC. Influence of method on estimates of normal knee extensor force among normal and postpolio children. Phys Ther Rev 1956;36:21–41.Google Scholar
  9. 9.
    Bechtol CO. Grip test: the use of a dynamometer with adjustable handle spacings. J Bone Joint Surg [Am] 1954;36:820–4.Google Scholar
  10. 10.
    Mathiowetz V, Kashman N, Volland G, Weber K, Dowe M, Rogers S. Grip and pinch strength: normative data for adults. Arch Phys Med Rehabil 1985;66:69–74.Google Scholar
  11. 11.
    Sinaki M. Relationship of muscle strength of back and upper extremity with level of physical activity in healthy women. Am J Phys Med Rehabil 1989;68:134–8.Google Scholar
  12. 12.
    Limburg PJ, Sinaki M, Bergstralh EJ, Miller JL, Squires RW. Correlations between physical activity, physical fitness, and back extensor strength in healthy, active young women. In: Christiansen C, Overgaard K, editors. Osteoporosis 1990. Copenhagen: Osteopress, 1990:1350–2.Google Scholar
  13. 13.
    Orwoll ES, Ferar J, Oviatt SK, McClung MR, Huntington K. The relationship of swimming exercise to bone mass in men and women. Arch Intern Med 1989;149:2197–200.Google Scholar
  14. 14.
    Rudins A, Sinaki M, Miller JL, Piper SM, Bergstralh EJ. Significance of back extensors versus back flexors in trunkal support [abstract]. Arch Phys Med Rehabil 1991;72:824.Google Scholar
  15. 15.
    Rogers J, Sinaki M, Bergstralh E, LimburgP, Wahner H. The effect of back extensor strength, physical activity, and vertebral bone density on postural change [abstract]. Arthritis Rheum 1990;33 (Suppl):S124.Google Scholar
  16. 16.
    Beiborn DS, Morrissey MC. A review of the literature related to trunk muscle performance. Spine 1988;13:655–60.Google Scholar

Copyright information

© European Foundation for Osteoporosis 1993

Authors and Affiliations

  • M. Sinaki
    • 1
  • S. Khosla
    • 1
  • P. J. Limburg
    • 1
  • J. W. Rogers
    • 1
  • P. A. Murtaugh
    • 1
  1. 1.Department of Physical Medicine and Rehabilitation, the Division of Endocrinology, Metabolism, and Internal Medicine, and the Section of BiostatisticsMayo Clinic and Mayo FoundationRochesterUSA

Personalised recommendations