Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial

Peter M Wayne, Julie E Buring, Roger B Davis, Ellen M Connors, Paolo Bonato, Benjamin Patritti, Mary Fischer, Gloria Y Yeh, Calvin J Cohen, Danette Carroll, Douglas P Kiel, Peter M Wayne, Julie E Buring, Roger B Davis, Ellen M Connors, Paolo Bonato, Benjamin Patritti, Mary Fischer, Gloria Y Yeh, Calvin J Cohen, Danette Carroll, Douglas P Kiel

Abstract

Background: Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD) loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength) are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks.

Methods/design: A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants' treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen), bone formation (osteocalcin), and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry). Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n = 16) to explore the feasibility of modeling skeletal mechanical loads and postural control as mediators of fracture risk.

Discussion: Results of this study will provide preliminary evidence regarding the value of Tai Chi as an intervention for decreasing fracture risk in osteopenic women. They will also inform the feasibility, value and potential limitations related to the use of pragmatic designs for the study of Tai Chi and related mind-body exercise. If the results are positive, this will help focus future, more in-depth, research on the most promising potential mechanisms of action identified by this study.

Trial registration: This trial is registered in ClinicalTrials.gov, with the ID number of NCT01039012.

Figures

Figure 1
Figure 1
Study flow diagram.

References

    1. Bone Health and Osteoporosis. A report of the Surgeon General. Rockville, MD: U.S: U.S. Department of Health and Human Services; 2004.
    1. Miller PD, Barlas S, Brenneman SK. An approach to identifying osteopenic women at increased short-term risk of fracture. Arch Intern Med. 2004;164(10):1113–1120. doi: 10.1001/archinte.164.10.1113.
    1. Harmer PA, Li F. Tai Chi and falls prevention in older people. Med Sport Sci. 2008;52:124–134. full_text.
    1. Wayne P, Krebs D, Wolf S. Can Tai-Chi improve vestibulopathic postural control? Arch Phys Med Rehabil. 2004;85(1):142–152. doi: 10.1016/S0003-9993(03)00652-X.
    1. Wolf S, Barnhart H, Ellison G, Coogler C. The effect of Tai Chi Quan and computerized balance training on postural stability in older subjects. Atlanta FICSIT Group. Frailty and Injuries: Cooperative Studies on Intervention Techniques. Phys Ther. 1997;77(4):371–381.
    1. Wolf S, Barnhart H, Kutner N, McNeely E, Coogler C, Xu T. Reducing frailty and falls in older persons: an investigation of Tai Chi and computerized balance training. J Am Geriatr Soc. 1996;44(5):489–497.
    1. Wayne PM, Kiel DP, Krebs DE. The effects of Tai Chi on bone mineral density in postmenopausal women: a systematic review. Arch Phys Med Rehabil. 2007;88(5):673–680. doi: 10.1016/j.apmr.2007.02.012.
    1. Shepherd A. An overview of osteoporosis. Alternative Therapies. 2004;10(2):26–33.
    1. Riggs B, Khosla S, Melton L III. Sex steroids and the construction and conservation of the adult skeleton. Endocr Rev. 2002;23(3):279–302. doi: 10.1210/er.23.3.279.
    1. Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. Report of a WHO Study Group. World Health Organ Tech Rep Ser. 1994;843:1–129.
    1. Siris E, Miller P, Barrett-Connor E. Identification and fracture outcomes of undiagnosed low bone mineral density in postmenopausal women: results from the national osteoporosis risk assessment. JAMA. 2001;286(22):2815–2822. doi: 10.1001/jama.286.22.2815.
    1. Melton L III. Adverse outcomes of osteoporotic fractures in the general population. J Bone Miner Res. 2003;18(6):1139–1141. doi: 10.1359/jbmr.2003.18.6.1139.
    1. Greendale G, Barrett-Connor E, Ingles S, Haile R. Late physical and functional effects of osteoporotic fracture in women: the Rancho Bernardo study. J Am Geriatr Soc. 1995;43:955–961.
    1. McClung MR. Osteopenia: to treat or not to treat? Ann Intern Med. 2005;142(9):796–797.
    1. National Osteoporosis Foundation. America's Bone Health: The State of Osteoporosis and Low Bone Mass in Our Nation: National Osteoporosis Foundation. Washington, DC; 2002.
    1. Berard A, Bravo G, Gauthier P. Meta-analyis of the effectiveness of physical activity for the prevention of bone loss in postmenopausal women. Osteoporosis Int. 1997;7:331–337. doi: 10.1007/BF01623773.
    1. Mayoux-Benhamou M, Roux C, Perraud A, Fermanian J, Rahali-Kachlouf H, Revel M. Predictors of compliance with a home-based exercise program added to usual medical care in preventing postmenopausal osteoporosis: an 18-month prospective study. Osteoporosis Int. 2005;16:325–331. doi: 10.1007/s00198-004-1697-z.
    1. Wallace B, Cummings R. Systematic review of randomized trials of the effect of exercise on bone mass in pre- and postmenopausal women. Calcif Tissue Int. 2000;67:10–18. doi: 10.1007/s00223001089.
    1. Cheng M. Master Cheng's Thirteen Chapters on T'ai Chi Chuan. New York, NY: Sweet Chi Press; 1982.
    1. Plummer J. In: The Scientific Basis of Traditional Chinese Medicine. Lau Y, editor. Hong Kong: University of Hong Kong; 1982. Acupuncture and tai chi chuan (Chinese shadow boxing): body-mind therapies affecting homeostasis.
    1. Frantzis B. The Power of Internal Matrial Arts: Combat Secrets of Ba Gua, Tai Chi, and Hsing-I. Berkeley, CA: North Atlantic Books; 1998.
    1. Wolf S, Coogler C, Xu T. Exploring the basis for Tai Chi Chuan as a therapeutic exercise approach. Arch Phys Med Rehabil. 1997;78:886–892. doi: 10.1016/S0003-9993(97)90206-9.
    1. Helm B. Gateways to health: Taijiquan and traditional Chinese medicine. Taijiquan Journal. 2002. pp. 8–12.
    1. Taylor-Pilae R, Froelicher E. The effectiveness of Tai Chi exercise in improving aerobic capacity, a meta-analysis. Journal of Cardiovascular Nursing. 2004;19(1):48–57.
    1. Wang C, Collet J, Lau J. The effect of Tai Chi on health outcomes in patients with chronic conditions. Arch Intern Med. 2004;164:493–501. doi: 10.1001/archinte.164.5.493.
    1. Li J, Hong Y, Chan K. Tai chi: physiological characteristics and beneficial effects on health. Br J Sports Med. 2001;35:118–156. doi: 10.1136/bjsm.35.3.148.
    1. Wu G. Evaluation of the effectiveness of Tai Chi for improving balance and preventing falls in the older population--a review. J Am Geriatr Soc. 2002;50:746–754. doi: 10.1046/j.1532-5415.2002.50173.x.
    1. Lan C, Lai J, Chen S. Tai Chi Chuan: an ancient wisdom on exercise and health promotion. Sports Med. 2002;32:217–224. doi: 10.2165/00007256-200232040-00001.
    1. Sandlund E, Norlander T. The effects of Tai Chi Chuan relaxation and exercise on stress responses and well-being: an overview of research. Int J Stress Manage. 2000;7:139–149. doi: 10.1023/A:1009536319034.
    1. Lee MS, Pittler MH, Ernst E. Is Tai Chi an effective adjunct in cancer care? A systematic review of controlled clinical trials. Support Care Cancer. 2007;15(6):597–601. doi: 10.1007/s00520-007-0221-3.
    1. Lee MS, Pittler MH, Kim MS, Ernst E. Tai chi for Type 2 diabetes: a systematic review. Diabet Med. 2008;25(2):240–241. doi: 10.1111/j.1464-5491.2007.02325.x.
    1. Li F, Harmer P, Fisher KJ. Tai Chi and fall reductions in older adults: a randomized controlled trial. J Gerontol A Biol Sci Med Sci. 2005;60(2):187–194.
    1. Sattin RW, Easley KA, Wolf SL, Chen Y, Kutner MH. Reduction in fear of falling through intense tai chi exercise training in older, transitionally frail adults. J Am Geriatr Soc. 2005;53(7):1168–1178. doi: 10.1111/j.1532-5415.2005.53375.x.
    1. Jacobson B, Chen H, Cashel C. The effect of Tai Chi Chuan training on balance, kinesthetic sense, and strength. Percept Mot Skills. 1997;84:27–33. doi: 10.2466/PMS.84.1.27-33.
    1. Judge JO, Lindsey C, Underwood M, Winsemius D. Balance improvements in older women: effects of exercise training. Phys Ther. 1993;73:254–262.
    1. Lan C, Lai J, Wong M. 12-month Tai Chi training in the elderly: its effect on health fitness. Med Sci Sports Exerc. 1998;30(3):345–351.
    1. Lan C, Lai J, Wong M. Cardiorespiratory function, flexibility, and body composition among geriatric Tai Chi Chuan practitioners. Arch Phys Med Rehabil. 1996;77:612–616. doi: 10.1016/S0003-9993(96)90305-6.
    1. Li F, McAuley E, Harmer P, Duncan T, Chaumeton N. Tai chi enhances self-efficacy and exercise behavior in older adults. J Aging Phys Act. 2001;9:161–171.
    1. Kutner N, Barnhart H, Wolf S, McNeely E, Xu T. Self-report benefits of Tai Chi practice by older adults. J Gerontol B Psychol Sci Soc Sci. 1997;52:242–246.
    1. Van Deusen J, Harlowe D. The efficacy of the ROM Dance Program for adults with rheumatoid arthritis. Am J Occup Ther. 1987;41(2):90–95.
    1. Sun W, Dosch M, Gilmore G. Effects of a Tai Chi Chuan program on Hmong American older adults. Educ Geronotol. 1996;22:161–167. doi: 10.1080/0360127960220202.
    1. Wilson C, Datta S. Tai Chi for the prevention of fractures in a nursing home population: an economic analysis. J Clin Outcomes Manage. 2001;8:19–27.
    1. Wolf S, Sattin R, Kutner N, O'Grady M, Greenspan A, Gregor R. Intense Tai Chi exercise training and fall occurences in older, transitionally frail adults: a randomized controlled trial. J Am Geriatr Soc. 2003;51:1693–1701. doi: 10.1046/j.1532-5415.2003.51552.x.
    1. Yeh G, Wood M, Lorell B. Effects of Tai-Chi mind-body movement therapy on functional status and exercise capacity in patients with chronic heart failure: a randomized controlled trial. Am J Med. 2004;117:541–548. doi: 10.1016/j.amjmed.2004.04.016.
    1. Lee MS, Pittler MH, Shin BC, Ernst E. Tai chi for osteoporosis: a systematic review. Osteoporos Int. 2008;19:139–46. doi: 10.1007/s00198-007-0486-x.
    1. Gong M, Zhang S, Wang B, Wang D. Effects of long-term shadowboxing exercise on bone mineral density in the aged. Chinese Journal of Clinical Rehabilitation. 2003;7:2238–2239.
    1. Qin L, Au S, Choy W. Regular Tai Chi Chuan exercise may retard bone loss in postmenopausal women: a case-control study. Arch Phys Med Rehabil. 2002;83:1355–1359. doi: 10.1053/apmr.2002.35098.
    1. Qin L, Choy W, Leung K. Beneficial effects of regular Tai Chi exercise on musculoskeletal system. J Bone Miner Metab. 2005;23:186–190. doi: 10.1007/s00774-004-0559-2.
    1. Zhou Y. The effect of traditional sports on the bone density of menopause women. Journal of Beijing Sport University. 2004;27:354–360.
    1. Woo J, Hong A, Lau E, Lynn H. A randomised controlled trial of Tai Chi and resistance exercise on bone health, muscle strength and balance in community-living elderly people. Age Ageing. 2007;36(3):262–268. doi: 10.1093/ageing/afm005.
    1. Bonaituti D, Shea B, Iovine R. Exercise for preventing and treating osteoporosis in postmenopausal women. Cochrane Database Syst Rev. 2002. p. CD000333.
    1. Martyn-St James M, Carroll S. Meta-analysis of walking for preservation of bone mineral density in postmenopausal women. Bone. 2008;43:521–531. doi: 10.1016/j.bone.2008.05.012.
    1. Yamazaki S, Ichimura S, Iwamoto J, Takeda T, Toyama Y. Effect of walking exercise on bone metabolism in postmenopausal women with osteopenia/osteoporosis. J Bone Miner Metab. 2004;22:500–508. doi: 10.1007/s00774-004-0514-2.
    1. Wu G, Liu W, Hitt J, Millon D. Spatial, temporal and muscle action patterns of Tai Chi gate. Journal of Electromyography and Kinesiology. 2004;14:343–354. doi: 10.1016/j.jelekin.2003.09.002.
    1. Mao DW, Hong Y, Li JX. Characteristics of foot movement in Tai Chi exercise. Phys Ther. 2006;86:215–222.
    1. Mao DW, Li JX, Hong Y. The duration and plantar pressure distribution during one-leg stance in Tai Chi exercise. Clin Biomech (Bristol, Avon) 2006;21:640–645. doi: 10.1016/j.clinbiomech.2006.01.008.
    1. Mao DW, Li JX, Hong Y. Plantar pressure distribution during Tai Chi exercise. Arch Phys Med Rehabil. 2006;87:814–820. doi: 10.1016/j.apmr.2006.02.035.
    1. Wu G, Hitt J. Ground contact characteristics of Tai Chi gait. Gait Posture. 2005;22:32–39. doi: 10.1016/j.gaitpost.2004.06.005.
    1. Wu G. Age-related differences in Tai Chi gait kinematics and leg muscle electromyography: a pilot study. Arch Phys Med Rehabil. 2008;89:351–357. doi: 10.1016/j.apmr.2007.08.147.
    1. Xu DQ, Li JX, Hong Y. Effects of long term Tai Chi practice and jogging exercise on muscle strength and endurance in older people. Br J Sports Med. 2006;40:50–54. doi: 10.1136/bjsm.2005.019273.
    1. McGibbon C, Krebs D, Parker S, Scarborough D, Wayne P, Wolf S. Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: preliminary report. BMC Neurology. 2005;5:3. doi: 10.1186/1471-2377-5-3.
    1. Wayne P, Kaptchuk T. Challenges inherent to Tai Chi research: Part I--Tai Chi as a complex multi-component intervention. J Altern Complement Med. 2008;14:95–102. doi: 10.1089/acm.2007.7170A.
    1. Wayne P, Kaptchuk T. Challenges inherent to Tai Chi Research: Part II--Defining the intervention adn optimal study design. J Altern Complement Med. 2008;14:191–197. doi: 10.1089/acm.2007.7170B.
    1. Roland M, Torgerson DJ. What are pragmatic trials? Bmj. 1998;316(7127):285.
    1. Thorpe KE, Zwarenstein M, Oxman AD. A pragmatic-explanatory continuum indicator summary (PRECIS): a tool to help trial designers. Cmaj. 2009;180:E47–57.
    1. Macpherson H. Pragmatic clinical trials. Complement Ther Med. 2004;12(2-3):136–140. doi: 10.1016/j.ctim.2004.07.043.
    1. Vickers AJ, Rees RW, Zollman CE. Acupuncture for chronic headache in primary care: large, pragmatic, randomised trial. BMJ. 2004;328(7442):744. doi: 10.1136/bmj.38029.421863.EB.
    1. Witt CM, Jena S, Selim D. Pragmatic randomized trial evaluating the clinical and economic effectiveness of acupuncture for chronic low back pain. Am J Epidemiol. 2006;164:487–496. doi: 10.1093/aje/kwj224.
    1. Garnero P, Borel O, Delmas PD. Evaluation of a fully automated serum assay for C-terminal cross-linking telopeptide of type I collagen in osteoporosis. Clin Chem. 2001;47:694–702.
    1. Fall PM, Kennedy D, Smith JA, Seibel MJ, Raisz LG. Comparison of serum and urine assays for biochemical markers of bone resorption in postmenopausal women with and without hormone replacement therapy and in men. Osteoporos Int. 2000;11:481–485. doi: 10.1007/s001980070089.
    1. Chailurkit LO, Ongphiphadhanakul B, Piaseu N, Saetung S, Rajatanavin R. Biochemical markers of bone turnover and response of bone mineral density to intervention in early postmenopausal women: an experience in a clinical laboratory. Clin Chem. 2001;47:1083–1088.
    1. Looker A, Bauer D, Chesnut C. Clinical use of biochemical markers of bone remodeling: Current status and future directions. Osteoporosis Int. 2000;11:467–480. doi: 10.1007/s001980070088.
    1. Garnero P, Delmas P. Biochemical markers of bone turnover. Applications for osteoporosis. Endocrinol Metab Clin North Am. 1998;27:303–323. doi: 10.1016/S0889-8529(05)70007-4.
    1. Xu H, Lawson D, Kras A. A study on Tai Ji exercise and traditional Chinese medical modalities in relation to bone structure, bone function and menopausal symptoms. Journal of Chinese Medicine. 2004;74:3–7.
    1. Heuck C, Wolthers O. A placebo-controlled study of three osteocalcin assays for assessment of prednisolone-induced suppression of bone turnover. Journal of Endocrinology. 1998;159:127–131. doi: 10.1677/joe.0.1590127.
    1. Hannan MT, Tucker KL, Dawson-Hughs B, Cupples LA, Felson DT, Kiel DP. Effect of dietary protein on bone loss in elderly men and women: the Framingham Osteoporosis Study. J Bone Miner Res. 2000;15:2504–2512. doi: 10.1359/jbmr.2000.15.12.2504.
    1. Blake G, Fogelman I. Technical principles of dual energy x-ray absorbtiometry. Semin Nucl Med. 1997. pp. 10–28.
    1. Genant H, Majumdar S. High-resolution magnetic resonance imaging of trabecular bone structure. Osteoporosis Int. 1997;7(Suppl 3):S135–139.
    1. Faulkner K, Von Stetten E, Miller P. Discordance in patient classification using t-scores. J Clin Densitom. 1999;2:343. doi: 10.1385/JCD:2:3:343.
    1. Lai J, Wong M, Lan C. Cardiorespiratory responses of Tai Chi Chuan practitioners and sedentary subjects during cycle ergometry. J Formos Med Assoc. 1993;92:894–899.
    1. Young D, Appel L, Lee S. The effects of aerobic exercise and T'ai Chi on blood pressure in older people: results of a randomized trial. J Am Geriatr Soc. 1999;47:277–284.
    1. Lan C, Chen S, Lai J, Wong M. The effect of Tai Chi on cardiorespiratory function in patients with coronary artery bypass surgery. Med Sci Sports Exerc. 1999;31:634–638. doi: 10.1097/00005768-199905000-00002.
    1. Channer K, Barrow D, Barrow R, Osborne M, Ives G. Changes in haemodynamic parameters following Tai Chi Chuan and aerobic exercise in patients recovering from acute myocardial infarction. Postgrad Med J. 1996;72:349–351. doi: 10.1136/pgmj.72.848.349.
    1. Sattin R, Easley K, Wolf S, Chen Y, Kutner M. Reduction in fear of falling through intense Tai Chi exercise training in older, transitionally frail adults. J Am Geriatr Soc. 2005;53:1168–1178. doi: 10.1111/j.1532-5415.2005.53375.x.
    1. Li F, Fisher KJ, Harmer P, Irbe D, Tearse RG, Weimer C. Tai Chi and self-rated quality of sleep and daytime sleepiness in older adults: a randomized controlled trial. J Am Geriatr Soc. 2004;52:892–900. doi: 10.1111/j.1532-5415.2004.52255.x.
    1. Ware JE, Sherbourne CD. The MOS 36-item short-form health survey (SF-36): a conceptual framework and item selection. Med Care. 1992;30:473–483. doi: 10.1097/00005650-199206000-00002.
    1. Lajoie Y, Gallagher SP. Predicting falls within the elderly community: comparison of postural sway, reaction time, the Berg balance scale and the Activities-specific Balance Confidence (ABC) scale for comparing fallers and non-fallers. Arch Gerontol Geriatr. 2004;38:11–26. doi: 10.1016/S0167-4943(03)00082-7.
    1. Myers AM, Fletcher PC, Myers AH, Sherk W. Discriminative and evaluative properties of the activities-specific balance confidence (ABC) scale. J Gerontol A Biol Sci Med Sci. 1998;53:M287–294.
    1. Powell LE, Myers AM. The Activities-specific Balance Confidence (ABC) Scale. J Gerontol A Biol Sci Med Sci. 1995;50A:M28–34.
    1. Utian WH, Janata JW, Kingsberg SA, Schluchter M, Hamilton JC. The Utian Quality of Life (UQOL) Scale: development and validation of an instrument to quantify quality of life through and beyond menopause. Menopause. 2002;9:402–410. doi: 10.1097/00042192-200211000-00005.
    1. Kalish LA, Buczynski B, Connell P. Stop Hypertension with the Acupuncture Research Program (SHARP): clinical trial design and screening results. Control Clin Trials. 2004;25:76–103. doi: 10.1016/j.cct.2003.08.006.
    1. Linde K, Witt CM, Streng A. The impact of patient expectations on outcomes in four randomized controlled trials of acupuncture in patients with chronic pain. Pain. 2007;128:264–271. doi: 10.1016/j.pain.2006.12.006.
    1. Gross L, Sallis J, Buono M, Roby J, Nelson J. Reliability of interviewers using the seven-day activity recall. Res Q Exerc Sport. 1990;61:321–325.
    1. Blair S. In: How to assess exercise habits and physical fitness. Matarazzo J, editor. Behavioral Health. New York: Wiley; 1984. pp. 424–447.
    1. Sarkin J, Nichols J, Sallis J, Calfas R. Self-report measures and scoring protocols affect prevalence estimates of meeting physical activity guidelines. Med Sci Sports Exerc. 2000;32:149–156. doi: 10.1097/00005768-200001000-00022.
    1. Chien M, Wu Y, Yang R, Lai J, Hsu A. Physical activity, physical fitness, and osteopenia in postmenopausal Taiwanese women. J Formos Med Assoc. 2000;99(1):11–17.
    1. Sallis J, Haskell W, Wood P. Physical activity assessment methodology in the Five-City Project. Am J Epidemiol. 1985;121:91–106.
    1. Hayden-Wade H, Coleman K, Sallis J, Armstrong C. Validation of the telephone and in-person interview versions of the 7-day PAR. Med Sci Sports Exerc. 2003;35:801–809. doi: 10.1249/01.MSS.0000064941.43869.4E.
    1. Glaser BSA. The Discovery of Grounded Theory: Strategies for Qualitative Research. Chichago: Aldine Publishing Co; 1967.
    1. Collins JJ, Priplata AA, Gravelle DC, Niemi J, Harry J, Lipsitz LA. Noise-enhanced human sensorimotor function. IEEE Eng Med Biol Mag. 2003;22:76–83. doi: 10.1109/MEMB.2003.1195700.
    1. Priplata AA, Patritti BL, Niemi JB. Noise-enhanced balance control in patients with diabetes and patients with stroke. Ann Neurol. 2006;59:4–12. doi: 10.1002/ana.20670.
    1. Collins JJ, De Luca CJ. Open-loop and closed-loop control of posture: a random-walk analysis of center-of-pressure trajectories. Exp Brain Res. 1993;95:308–318. doi: 10.1007/BF00229788.
    1. Hurwitz DE, Foucher KC, Sumner DR, Andriacchi TP, Rosenberg AG, Galante JO. Hip motion and moments during gait relate directly to proximal femoral bone mineral density in patients with hip osteoarthritis. J Biomech. 1998;31:919–925. doi: 10.1016/S0021-9290(98)00097-9.
    1. Moisio KC, Hurwitz DE, Sumner DR. Dynamic loads are determinants of peak bone mass. J Orthop Res. 2004;22:339–345. doi: 10.1016/j.orthres.2003.08.002.
    1. Hof AL. The equations of motion for a standing human reveal three mechanisms for balance. J Biomech. 2007;40:451–457. doi: 10.1016/j.jbiomech.2005.12.016.
    1. Sayers SP, Bean J, Cuoco A, LeBrasseur NK, Jette A, Fielding RA. Changes in function and disability after resistance training: does velocity matter?: a pilot study. Am J Phys Med Rehabil. 2003;82:605–613. doi: 10.1097/00002060-200308000-00007.
    1. Shumway-Cook A, Brauer S, Woollacott M. Predicting the probability for falls in community-dwelling older adults using the Timed Up & Go Test. Phys Ther. 2000;80:896–903.
    1. Perell KL, Nelson A, Goldman RL, Luther SL, Prieto-Lewis N, Rubenstein LZ. Fall risk assessment measures: an analytic review. J Gerontol A Biol Sci Med Sci. 2001;56:M761–766.
    1. Berg KO, Wood-Dauphinee SL, Williams JI, Maki B. Measuring balance in the elderly: validation of an instrument. Can J Public Health. 1992;83(Suppl 2):S7–11.
    1. Cho CY, Kamen G. Detecting balance deficits in frequent fallers using clinical and quantitative evaluation tools. J Am Geriatr Soc. 1998;46:426–430.
    1. Hurvitz EA, Richardson JK, Werner RA, Ruhl AM, Dixon MR. Unipedal stance testing as an indicator of fall risk among older outpatients. Arch Phys Med Rehabil. 2000;81(5):587–591. doi: 10.1016/S0003-9993(00)90039-X.
    1. Runge M, Hunter G. Determinants of musculoskeletal frailty and the risk of falls in old age. J Musculoskelet Neuronal Interact. 2006;6(2):167–173.
    1. Brotherton SS, Williams HG, Gossard JL, Hussey JR, McClenaghan BA, Eleazer P. Are measures employed in the assessment of balance useful for detecting differences among groups that vary by age and disease state? J Geriatr Phys Ther. 2005;28(1):14–19.

Source: PubMed

3
Tilaa