Exercise and frailty in later life: A systematic review and bibliometric analysis of research themes and scientific collaborations

Abstract

Exercise is a promising intervention for frailty, but optimal protocols and implementation approaches remain unclear. In this review, a bibliometric analysis was conducted to synthesize research growth, collaborations, intellectual structure, and gaps in the literature on frailty and exercise over the past two decades. The Web of Science and Scopus databases were searched for relevant publications from 1987 - 2024. The bibliometric analysis examined publication trends over time, contributing countries, institutions, authors, journals, research themes and hotspots, collaboration patterns, and evidence gaps. Data visualization and mapping were conducted using VOSviewer, Biblioshiny, and ScientoPy. A total of 447 publications were included in the analysis. The results indicate that research output has grown rapidly since 2010, led by the United States of America (USA), China, Japan, Spain, and Italy. The University of Valencia (n = 12) and the School of Medicine, USA (n = 11) were the most prolific institutions. Five key research clusters were identified through keyword analysis: (i) Frailty assessment, (ii) clinical trials, (iii) cognition, (iv) exercise protocols, and (v) physical outcomes. Regional collaborations were prominent between European, North American, and East Asia-Pacific countries. The bibliometric analysis revealed a surge in publications, with research concentrated in a few productive hubs. There is potential for newer institutions to emerge through international collaborations. Addressing gaps in qualitative, psychosocial, economic, implementation, and translational research could accelerate the translation of evidence into policy and practice. Continued knowledge sharing and partnerships focused on priority gaps can optimize exercise interventions amidst global population aging. This review synthesized the growth, collaborative landscape, and intellectual structure of research on frailty and exercise over nearly four decades. The findings provide insights to inform future research directions and facilitate the translation of evidence into optimized exercise protocols that can be implemented at scale to benefit frail older adults.

Keywords

Bibliometric analysis / Exercise / Frailty / Content analysis

Funding

This study was funded by the Ministry of Higher Education (MOHE), Malaysia, under the Fundamental Research Grant Scheme (FRGS) (FRGS/1/2022/WAB01/ UITM/02/4) and has been approved by the Medical Research and Ethics Committee, Universiti Teknologi MARA (FERC/FSK/MR/2023/00296).

Conflict of interest

The author declares that she has no competing interests.

References

[1] Aguirre L.E., & Villareal D.T. (2019). Physical exercise as therapy for frailty. Nestlé Nutrition Institute Workshop Series, 83:83-92. https://doi.org/10.1159/000382065

[2] Ahn E., & Kang H. (2018). Introduction to systematic review and meta-analysis. Korean Journal of Anesthesiology, 71(2):103-112. https://doi.org/10.4097/kjae.2018.71.2.103

[3] Akobeng A.K. (2005). Understanding randomised controlled trials. Archives of Disease in Childhood, 90(8):840-844. https://doi.org/10.1136/adc.2004.058222

[4] Angulo J., El Assar M., Álvarez-Bustos A., & Rodríguez-Mañas L. (2020). Physical activity and exercise: Strategies to manage frailty. Redox Biology, 35:101513. https://doi.org/10.1016/j.redox.2020.101513

[5] Apóstolo J., Cooke R., Bobrowicz-Campos E., Santana S., Marcucci M., Cano A., et al. (2018). Effectiveness of interventions to prevent pre-frailty and frailty progression in older adults. JBI Database of Systematic Reviews and Implementation Reports, 16(1):140-232. https://doi.org/10.11124/jbisrir-2017-003382

[6] Azizan A. (2024). Mapping the muscle mass: A birds-eye view of sarcopenia research through Bibliometric network analysis. International Journal of Disabilities Sports and Health Sciences, 7(1):134-143. https://doi.org/10.33438/ijdshs.1362539

[7] Azizan A., & Zaki A. (2023). Educational insights from bibliometric patterns: Examining depression research in Malaysia. Asian Journal of Research in Education and social Sciences, 5(3):33-47.

[8] Azizan A., Abdullah K.H., Rahayu S.R., Rusli N.S., & Tarmidzi N. (2023). Reshaping healthcare: A bibliometric analysis of lessons learned in post-COVID-19 health policy. Kesmas: Jurnal Kesehatan Masyarakat Nasional, 18(3):18. https://doi.org/10.21109/kesmas.v18i3.7060

[9] Azizan A., Azmi A., & Putera Mohd Yusof M.Y. (2024). Bibliometric analysis on geriatric rehabilitation in scopus database ( 1948-2022). Topics in Geriatric Rehabilitation, 40(1):60-68. https://doi.org/10.1097/tgr.0000000000000423

[10] Azizan A., Sahrani S., Anum A., Husna N., & Rahman F. (2021). Effects of physical training and behavioural strategies towards muscle strength and mental health in the elderly. Malaysian Applied Biology, 50(2):177-184. https://doi.org/10.55230/mabjournal.v50i2.2159

[11] Bandeen-Roche K., Seplaki C.L., Huang J., Buta B., Kalyani R.R., Varadhan R., et al. (2015). Frailty in older adults: A nationally representative profile in the United States. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 70(11):1427-1434. https://doi.org/10.1093/gerona/glv133

[12] Binder E.F., Yarasheski K.E., Steger-May K., Sinacore D.R., Brown M., Schechtman K.B., et al. (2005). Effects of progressive resistance training on body composition in frail older adults: Results of a randomized, controlled trial. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 60(11):1425-1431. https://doi.org/10.1093/gerona/60.11.1425

[13] Boreskie K.F., Hay J.L., Boreskie P.E., Arora R.C., & Duhamel T.A. (2022). Frailty-aware care: Giving value to frailty assessment across different healthcare settings. BMC Geriatrics, 22(1):13. https://doi.org/10.1186/s12877-021-02722-9

[14] Brigola A.G., Rossetti E.S., Dos Santos B.R., Neri A.L., Zazzetta M.S., Inouye K., et al. (2015). Relationship between cognition and frailty in elderly: A systematic review. Dementia and Neuropsychologia, 9(2):110-119. https://doi.org/10.1590/1980-57642015dn92000005

[15] Cancela J.M., Ayán C., Varela S., & Seijo M. (2016). Effects of a long-term aerobic exercise intervention on institutionalized patients with dementia. Journal of Science and Medicine in Sport, 19(4):293-298. https://doi.org/10.1016/j.jsams.2015.05.007

[16] Casas-Herrero A., Anton-Rodrigo I., Zambom-Ferraresi F., Sáez de Asteasu M.L., Martinez-Velilla N., Elexpuru- Estomba J., et al. (2019). Effect of a multicomponent exercise programme (VIVIFRAIL) on functional capacity in frail community elders with cognitive decline: Study protocol for a randomized multicentre control trial. Trials, 20(1):362. https://doi.org/10.1186/s13063-019-3426-0

[17] Cesari M., Vellas B., Hsu F.C., Newman A.B., Doss H., King A.C., et al. (2014). A physical activity intervention to treat the frailty syndrome in older persons--results from the LIFE-P study. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 70(2):216-222. https://doi.org/10.1093/gerona/glu099

[18] Clegg A., Rogers L., & Young J. (2014). Diagnostic test accuracy of simple instruments for identifying frailty in community-dwelling older people: A systematic review. Age and Ageing, 44(1):148-152. https://doi.org/10.1093/ageing/afu157

[19] Clegg A., Young J., Iliffe S., Rikkert M.O., & Rockwood K. (2013). Frailty in elderly people. The Lancet, 381(9868):752-762. https://doi.org/10.1016/s0140-6736(12)62167-9

[20] De Labra C., Guimaraes-Pinheiro C., Maseda A., Lorenzo T., & Millán-Calenti J.C. (2015) Effects of physical exercise interventions in frail older adults: A systematic review of randomized controlled trials. BMC Geriatrics, 15(1):154. https://doi.org/10.1186/s12877-015-0155-4

[21] Dent E., Morley J.E., Cruz-Jentoft A.J., Woodhouse L., Rodríguez-Mañas L., Fried L.P., et al. (2019). Physical frailty: ICFSR international clinical practice guidelines for identification and management. The Journal of Nutrition, Health and Aging, 23(9):771-787. https://doi.org/10.1007/s12603-019-1273-z

[22] DeVito C.A., Morgan R.O., Duque M., Abdel-Moty E., & Virnig B.A. (2003). Physical performance effects of low-intensity exercise among clinically defined high-risk elders. Gerontology, 49(3):146-154. https://doi.org/10.1159/000069168

[23] Dipietro L., Campbell W.W., Buchner D.M., Erickson K.I., Powell K.E., Bloodgood B., et al. (2019). Physical Activity, injurious falls, and physical function in aging. Medicine and Science in Sports and Exercise, 51(6):1303-1313. https://doi.org/10.1249/mss.0000000000001942

[24] Edna Mayela D.L.V.C., Miriam L.T., Ana Isabel G.G., Oscar R.C., & Alejandra C.A. (2023). Effectiveness of an online multicomponent physical exercise intervention on the physical performance of community-dwelling older adults: A randomized controlled trial. Geriatric Nursing, 54:83-93. https://doi.org/10.1016/j.gerinurse.2023.08.018

[25] Evans W.J., Guralnik J., Cawthon P., Appleby J., Landi F., Clarke L., et al. (2023). Sarcopenia: No consensus, no diagnostic criteria, and no approved indication-how did we get here? Geroscience, 46:183-190. https://doi.org/10.1007/s11357-023-01016-9

[26] Feng L., Zin Nyunt M.S., Gao Q., Feng L., Yap K.B., Ng T.P. (2017). Cognitive frailty and adverse health outcomes: Findings from the singapore longitudinal ageing studies (SLAS). Journal of the American Medical Directors Association, 18(3):252-258. https://doi.org/10.1016/j.jamda.2016.09.015

[27] Fent T. (2008). Department of economic and social affairs, population division, united nations expert group meeting on social and economic implications of changing population age structures. European Journal of Population, Revue Européenne de Démographie, 24(4):451-452. https://doi.org/10.1007/s10680-008-9165-7

[28] Fetscherin M., & Heinrich D. (2015). Consumer brand relationships research: A bibliometric citation meta-analysis. Journal of Business Research, 68(2):380-390. https://doi.org/10.1016/j.jbusres.2014.06.010

[29] Fiatarone M.A., O’Neill E.F., Ryan N.D., Clements K.M., Solares G.R., Nelson M.E., et al. (1994). Exercise training and nutritional supplementation for physical frailty in very elderly people. New England Journal of Medicine, 330(25):1769-1775. https://doi.org/10.1056/nejm199406233302501

[30] Flores-Bello C., Correa-Muñoz E., Sánchez-Rodríguez M.A., & Víctor Manuel Mendoza-Núñez. (2024). Effect of Exercise programs on physical performance in community-dwelling older adults with and without frailty: Systematic review and meta-analysis. Geriatrics, 9(1):8. https://doi.org/10.3390/geriatrics9010008

[31] Gené Huguet L., Navarro González M., Kostov B., Ortega Carmona M., Colungo Francia C., Hervás Docón A., et al. (2018). Pre frail 80: Multifactorial intervention to prevent progression of pre-frailty to frailty in the elderly. The Journal of Nutrition, Health and Aging, 22(10):1266-1274. https://doi.org/10.1007/s12603-018-1089-2

[32] Gill T.M., Baker D.I., Gottschalk M., Peduzzi P.N., Allore H., Byers A. (2002). A program to prevent functional decline in physically frail, elderly persons who live at home. New England Journal of Medicine, 347(14):1068-1074. https://doi.org/10.1056/nejmoa020423

[33] Gschwind Y.J., Kressig R.W., Lacroix A., Muehlbauer T., Pfenninger B., & Granacher U. (2013). A best practice fall prevention exercise program to improve balance, strength/ power, and psychosocial health in older adults: Study protocol for a randomized controlled trial. BMC Geriatrics, 13(1):105. https://doi.org/10.1186/1471-2318-13-105

[34] Han S., Gao T., Mo G., Liu H., & Zhang M. (2023). Bidirectional relationship between frailty and cognitive function among Chinese older adults. Archives of Gerontology and Geriatrics, 114:105086-105086. https://doi.org/10.1016/j.archger.2023.105086

[35] Huang C.H., Umegaki H., Makino T., Uemura K., Hayashi T., Kitada T., et al. (2020). Effect of various exercises on frailty among older adults with subjective cognitive concerns: A randomised controlled trial. Age and Ageing, 49(6):1011-1019. https://doi.org/10.1093/ageing/afaa086

[36] Hui Z., Wang X., Zhou Y., Li Y., Ren X., & Wang M. (2022). Global research on cognitive frailty: A bibliometric and visual analysis of papers published during 2013-2021. International Journal of Environmental Research and Public Health, 19(13):8170. https://doi.org/10.3390/ijerph19138170

[37] Hwang H.F., Suprawesta L., Chen S.J., Yu W., & Lin M.R. (2023). Predictors of incident reversible and potentially reversible cognitive frailty among Taiwanese older adults. BMC Geriatrics, 23(1):24. https://doi.org/10.1186/s12877-023-03741-4

[38] Ip E.H., Church T., Marshall S.A., Zhang Q., Marsh A.P., Guralnik J., et al. (2012). Physical activity increases gains in and prevents loss of physical function: Results from the lifestyle interventions and independence for elders pilot study. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 68(4):426-432. https://doi.org/10.1093/gerona/gls186

[39] Iskandar I., Joanny A., Azizan A., & Justine M. (2021). The prevalence of sarcopenia and its impact on quality of life in elderly residing in the community. Malaysian Journal of Medicine and Health Sciences, 17(3):261-266.

[40] Izquierdo M., Merchant R.A., Morley J.E., Anker S.D., Aprahamian I., Arai H., et al. (2021). International Exercise Recommendations in Older Adults (ICFSR): Expert Consensus Guidelines. The Journal of Nutrition, Health and Aging, 25(7):824-853. https://doi.org/10.1007/s12603-021-1665-8

[41] Jeong H.N., Chang S.J., Kim J.R., & Choi G.W. (2022). Interventions to prevent the frailty in older women with frailty: A systematic review and meta-analysis. Innovation in Aging, 6(Suppl 1):562-562. https://doi.org/10.1093/geroni/igac059.2120

[42] Kasim N.F., Veldhuijzen van Zanten J., & Aldred S. (2020). Tai Chi is an effective form of exercise to reduce markers of frailty in older age. Experimental Gerontology, 135:110925. https://doi.org/10.1016/j.exger.2020.110925

[43] Kolle A.T., Lewis K.B., Lalonde M., & Backman C. (2023). Reversing frailty in older adults: A scoping review. BMC Geriatrics, 23(1):751. https://doi.org/10.1186/s12877-023-04309-y

[44] Kovács É., Prokai L., Mészáros L., & Gondos T. (2013). Adapted physical activity is beneficial on balance, functional mobility, quality of life and fall risk in community-dwelling older women: A randomized single-blinded controlled trial. European Journal of Physical and Rehabilitation Medicine, 49(3):301-310.

[45] Lafrenière S., Folch N., Dubois S., Bédard L., & Ducharme F. (2016). Strategies used by older patients to prevent functional decline during hospitalization. Clinical Nursing Research, 26(1):6-26. https://doi.org/10.1177/1054773815601392

[46] Lee L.Y.K., & Chu E.C.P. (2023). Tai chi as a body-mind exercise for promotion of healthy aging in nursing home residents: Appropriateness, feasibility, and effectiveness. Clinical Interventions in Aging, 18:1949-1959. https://doi.org/10.2147/CIA.S430968

[47] Leng S., Chen X., & Mao G. (2014). Frailty syndrome: An overview. Clinical Interventions in Aging, 9:433-441. https://doi.org/10.2147/cia.s45300

[48] Li C., Ge S., Yin Y., Tian C., Mei Y., & Han P. (2023). Frailty is associated with worse cognitive functioning in older adults. Frontiers in Psychiatry, 14:1108902. https://doi.org/10.3389/fpsyt.2023.1108902

[49] Li L., Catalá-López F., Alonso-Arroyo A., Tian J., Aleixandre- Benavent R., Pieper D., et al. (2016). The global research collaboration of network meta-analysis: A social network analysis. Plos One, 11(9):e0163239. https://doi.org/10.1371/journal.pone.0163239

[50] Li X., Zhang Y., Tian Y., Cheng Q., Gao Y., & Gao M. (2022). Exercise interventions for older people with cognitive frailty-a scoping review. BMC Geriatrics, 22(1):721. https://doi.org/10.1186/s12877-022-03370-3

[51] Ligezka A.N., Mohamed A., Pascoal C., Ferreira V.D.R., Boyer S., Lam C., et al. (2022). Patient-reported outcomes and quality of life in PMM2-CDG. Molecular Genetics and Metabolism, 136(2):145-151. https://doi.org/10.1016/j.ymgme.2022.04.002

[52] Lin Y., Chen C.Y., Shuk D., Montayre J., Lee C.Y., & Ho M. (2022). The relationship between physical activity trajectories and frailty: A 20-year prospective cohort among community-dwelling older people. BMC Geriatrics, 22(1):867. https://doi.org/10.1186/s12877-022-03493-7

[53] Lutz W., Sanderson W., & Scherbov S. (2008). The coming acceleration of global population ageing. Nature, 451(7179):716-719. https://doi.org/10.1038/nature06516

[54] Mauricio V.G., Daniel R., & Duque G. (2024). Exercise as a therapeutic tool in age-related frailty and cardiovascular disease: Challenges and strategies. Canadian Journal of Cardiology, 40:1458-1467. https://doi.org/10.1016/j.cjca.2024.01.005

[55] Meunier A., Longworth L., Kowal S., Ramagopalan S., Love- Koh J., & Griffin S. (2022). Distributional cost-effectiveness analysis of health technologies: Data requirements and challenges. Value in Health, 2023:60-63. https://doi.org/10.1016/j.jval.2022.06.011

[56] Money A., Harris D., Hawley-Hague H., McDermott J., Vardy E., & Todd C. (2023). Acceptability of physical activity signposting for pre-frail older adults: A qualitative study to inform intervention development. BMC Geriatrics, 23(1):621. https://doi.org/10.1186/s12877-023-04202-8

[57] Mugueta-Aguinaga I., & Garcia-Zapirain B. (2017). Is technology present in frailty? technology a back-up tool for dealing with frailty in the elderly: A systematic review. Aging and Disease, 8(2):2005. https://doi.org/10.14336/ad.2016.0901

[58] Mulasso A., Roppolo M., Rainoldi A., & Rabaglietti E. (2022). Effects of a multicomponent exercise program on prevalence and severity of the frailty syndrome in a sample of Italian community-dwelling older adults. Healthcare, 10(5):911. https://doi.org/10.3390/healthcare10050911

[59] Muscedere J., Afilalo J., Araujo de Carvalho I., Cesari M., Clegg A., Eriksen H.E., et al. (2019). Moving towards common data elements and core outcome measures in frailty research. Journal of Frailty and Aging, 9(1):14-22. https://doi.org/10.14283/jfa.2019.43

[60] Nagai K., Miyamato T., Okamae A., Tamaki A., Fujioka H., Wada Y., et al. (2018). Physical activity combined with resistance training reduces symptoms of frailty in older adults: A randomized controlled trial. Archives of Gerontology and Geriatrics, 76:41-47. https://doi.org/10.1016/j.archger.2018.02.005

[61] Negm A.M., Kennedy C.C., Thabane L., Veroniki A.A., Adachi J.D., Richardson J., et al. (2017). Management of frailty: A protocol of a network meta-analysis of randomized controlled trials. Systematic Reviews, 6(1):130. https://doi.org/10.1186/s13643-017-0522-7

[62] Negm A.M., Kennedy C.C., Thabane L., Veroniki A.A., Adachi J.D., Richardson J., et al. (2019). Management of frailty: A systematic review and network meta-analysis of randomized controlled trials. Journal of the American Medical Directors Association, 20(10):1190-1198. https://doi.org/10.1016/j.jamda.2019.08.009

[63] Neto S., Rosa S., Freire M.D., Correa H.L., Pedreira R.C., Dias F.C.F., et al. (2023). Geriatric and gerontology research: A scientometric investigation of open access journal articles indexed in the scopus database. Annals of Geriatric Medicine and Research, 27(3):183-191. https://doi.org/10.4235/agmr.23.0076

[64] Niazi S.K., Greenberg-Worisek A.J., Smith J.L., Matthews A., Boyum P.P., Nordan L., et al. (2022). Exploring the patient experience with patient-reported outcomes: A qualitative, multistakeholder study. Southern Medical Journal, 115(9):653-657. https://doi.org/10.14423/smj.0000000000001438

[65] Okamura K. (2019). Interdisciplinarity revisited: Evidence for research impact and dynamism. Palgrave Communications, 5(1):1-9. https://doi.org/10.1057/s41599-019-0352-4

[66] Peng C., Burr J.A., Yuan Y., & Lapane K.L. (2023). Physical frailty and cognitive function among older chinese adults: The mediating roles of activities of daily living limitations and depression. Journal of Frailty and Aging, 12(3):156-165. https://doi.org/10.14283/jfa.2023.1

[67] Pialoux T., Goyard J., & Lesourd B. (2012). Screening tools for frailty in primary health care: A systematic review. Geriatrics and Gerontology International, 12(2):189-197. https://doi.org/10.1111/j.1447-0594.2011.00797.x

[68] Puts M.T.E., Toubasi S., Andrew M.K., Ashe M.C., Ploeg J., Atkinson E., et al. (2017). Interventions to prevent or reduce the level of frailty in community-dwelling older adults: A scoping review of the literature and international policies. Age and Ageing, 46(3):383-392. https://doi.org/10.1093/ageing/afw247

[69] Rahayu U.B., Rahman F., Setiyadi N.A., & Azizan A. (2021). Exercise and physical health in survivors of COVID-19: A scoping review. Journal of Medicinal and Chemical Sciences, 4(2):154-162. https://doi.org/10.26655/jmchemsci.2021.2.6

[70] Reeves D., Howells K., Sidaway M., Blakemore A., Hann M., Panagioti M., et al. (2018). The cohort multiple randomized controlled trial design was found to be highly susceptible to low statistical power and internal validity biases. Journal of Clinical Epidemiology, 95:111-119. https://doi.org/10.1016/j.jclinepi.2017.12.008

[71] Rodrigues F., Domingos C., Monteiro D., & Morouço P. (2022). A review on aging, sarcopenia, falls, and resistance training in community-dwelling older adults. International Journal of Environmental Research and Public Health, 19(2):874. https://doi.org/10.3390/ijerph19020874

[72] Rubenstein L.Z., Josephson K.R., Trueblood P.R., Loy S., Harker J.O., Pietruszka F.M., et al. (2000). Effects of a group exercise program on strength, mobility, and falls among fall-prone elderly men. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 55(6):M317-M321. https://doi.org/10.1093/gerona/55.6.m317

[73] Sadjapong U., Yodkeeree S., Sungkarat S., & Siviroj P. (2020). Multicomponent exercise program reduces frailty and inflammatory biomarkers and improves physical performance in community-dwelling older adults: A randomized controlled trial. International Journal of Environmental Research and Public Health, 17(11):3760. https://doi.org/10.3390/ijerph17113760

[74] Sarkies M.N., Robins L.M., Jepson M., Williams C.M., Taylor N.F., O’Brien L., et al. (2021). Effectiveness of knowledge brokering and recommendation dissemination for influencing healthcare resource allocation decisions: A cluster randomised controlled implementation trial. PLoS Medicine, 18(10):e1003833. https://doi.org/10.1371/journal.pmed.1003833

[75] Seguin R., & Nelson M. (2003). The benefits of strength training for older adults. American Journal of Preventive Medicine, 25(3):141-149. https://doi.org/10.1016/s0749-3797(03)00177-6

[76] Seldeen K.L., MacDonald B.A., & Troen B.R. (2022). Frailty:The End of the Osteosarcopenia Continuum? Netherlands: Elsevier EBooks. p. 239-253. https://doi.org/10.1016/b978-0-12-820088-9.00002-0

[77] Shamliyan T., Talley K.M.C., Ramakrishnan R., & Kane R.L. (2013). Association of frailty with survival: A systematic literature review. Ageing Research Reviews, 12(2):719-736. https://doi.org/10.1016/j.arr.2012.03.001

[78] Shears M., McGolrick D., Waters B., Jakab M., Boyd J.G., & Muscedere J. (2017). Frailty measurement and outcomes in interventional studies: Protocol for a systematic review of randomised control trials. BMJ Open, 7(12):e018872. https://doi.org/10.1136/bmjopen-2017-018872

[79] Sun M., Min L., Xu N., Huang L., & Li X. (2021). The effect of exercise intervention on reducing the fall risk in older adults: A meta-analysis of randomized controlled trials. International Journal of Environmental Research and Public Health, 18(23):12562. https://doi.org/10.3390/ijerph182312562

[80] Talar K., Hernández-Belmonte A., Vetrovsky T., Steffl M., Kałamacka E., & Courel-Ibáñez J. (2021). Benefits of resistance training in early and late stages of frailty and sarcopenia: A systematic review and meta-analysis of randomized controlled studies. Journal of Clinical Medicine, 10(8):1630. https://doi.org/10.3390/jcm10081630

[81] Tan R.S., Goh E.F., Wang D., Chung R., Zeng Z., Yeo A., et al. (2022). Effectiveness and usability of the system for assessment and intervention of frailty for community-dwelling pre-frail older adults: A pilot study. Frontiers in Medicine (Lausanne), 9: 955785. https://doi.org/10.3389/fmed.2022.955785

[82] Tawfik G.M., Dila K.A.S., Mohamed M.Y.F., Tam D.N.H., Kien N.D., Ahmed A.M., et al. (2019). A step by step guide for conducting a systematic review and meta-analysis with simulation data. Tropical Medicine and Health, 47(1):46. https://doi.org/10.1186/s41182-019-0165-6

[83] Travers J., Romero-Ortuno R., Bailey J., & Cooney M.T. (2018). Delaying and reversing frailty: A systematic review of primary care interventions. British Journal of General Practice, 69(678):e61-e69. https://doi.org/10.3399/bjgp18x700241

[84] Valenzuela P.L., Morales J.S., Castillo-García A., Mayordomo- Cava J., García-Hermoso A., Izquierdo M., et al. (2020). Effects of exercise interventions on the functional status of acutely hospitalised older adults: A systematic review and meta-analysis. Ageing Research Reviews, 61:101076. https://doi.org/10.1016/j.arr.2020.101076

[85] Valenzuela P.L., Ortiz-Alonso J., Bustamante-Ara N., Vidán M.T., Rodríguez-Romo G., Mayordomo-Cava J., et al. (2020). Individual responsiveness to physical exercise intervention in acutely hospitalized older adults. Journal of Clinical Medicine, 9(3):797. https://doi.org/10.3390/jcm9030797

[86] Vellas B., Balardy L., Gillette-Guyonnet S., Abellan Van Kan G., Ghisolfi-Marque A., Subra J., et al. (2013). Looking for frailty in community-dwelling older persons: The gerontopole frailty screening tool (GFST). The Journal of Nutrition, Health and Aging, 17(7):629-631. https://doi.org/10.1007/s12603-013-0363-6

[87] Vieira E.S., & Gomes J.A.N.F. (2009). A comparison of scopus and web of science for a typical university. Scientometrics, 81(2):587-600. https://doi.org/10.1007/s11192-009-2178-0

[88] Walsh B., Fogg C., Harris S., Roderick P., De Lusignan S., England T., et al. (2023). Frailty transitions and prevalence in an ageing population: Longitudinal analysis of primary care data from an open cohort of adults aged 50 and over in England, 2006- 2017. Age and Ageing, 52(5):afad058. https://doi.org/10.1093/ageing/afad058

[89] Wang Z., Meng D., He S., Guo H., Tian Z., Wei M., et al. (2022). The effectiveness of a hybrid exercise program on the physical fitness of frail elderly. International Journal of Environmental Research and Public Health, 19(17):11063. https://doi.org/10.3390/ijerph191711063

[90] Weening-Dijksterhuis E., De Greef M.H.G., Scherder E.J.A., Slaets J.P.J., & Van der Schans C.P. (2011). Frail institutionalized older persons. American Journal of Physical Medicine and Rehabilitation, 90(2):156-168. https://doi.org/10.1097/phm.0b013e3181f703ef

[91] Welstead M., Jenkins N.D., Russ T.C., Luciano M., & Muniz- Terrera G. (2020). A systematic review of frailty trajectories: Their shape and influencing factors. The Gerontologist, 61(8):e463-e475. https://doi.org/10.1093/geront/gnaa061

[92] Wolf S.L., O’Grady M., Easley K.A., Guo Y., Kressig R.W., & Kutner M. (2006). The influence of intense tai chi training on physical performance and hemodynamic outcomes in transitionally frail, older adults. The Journals of Gerontology: Series A, 61(2):184-189. https://doi.org/10.1093/gerona/61.2.184

[93] Wu C. (2023). Embracing complexity: New horizons in frailty research. The Lancet Regional Health-Western Pacific, 34:100791-100791. https://doi.org/10.1016/j.lanwpc.2023.100791

[94] Xue H., Huang C., Zhu Q., Zhou S., Ji Y., Ding X., et al. (2022). Relationships among cognitive function, frailty, and health outcome in community-dwelling older adults. Frontiers in Aging Neuroscience, 13:790251. https://doi.org/10.3389/fnagi.2021.790251

[95] Yi M., Zhang W., Zhang X., Zhou J., & Wang Z. (2023). The effectiveness of Otago Exercise Program in older adults with frailty or pre-frailty: A systematic review and meta-analysis. Archives of Gerontology and Geriatrics, 114:105083-105083. https://doi.org/10.1016/j.archger.2023.105083

[96] Yoon D.H., Lee J.Y., & Song W. (2018). Effects of resistance exercise training on cognitive function and physical performance in cognitive frailty: A randomized controlled trial. The Journal of Nutrition, Health and Aging, 22(8):944-951. https://doi.org/10.1007/s12603-018-1090-9

[97] Yu R., Leung G., & Woo J. (2021). Randomized controlled trial on the effects of a combined intervention of computerized cognitive training preceded by physical exercise for improving frailty status and cognitive function in older adults. International Journal of Environmental Research and Public Health, 18(4):1396. https://doi.org/10.3390/ijerph18041396