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Physical Exercise Interventions for Improving Performance-Based Measures of Physical Function in Community-Dwelling, Frail Older Adults: A Systematic Review and Meta-Analysis

Published:December 02, 2013DOI:https://doi.org/10.1016/j.apmr.2013.11.007

      Abstract

      Objective

      To conduct a systematic review to determine the efficacy of exercise-based interventions on improving performance-based measures of physical function and markers of physical frailty in community-dwelling, frail older people.

      Data Sources

      Comprehensive bibliographic searches in MEDLINE, the Cochrane Library, PEDro, and CINAHL databases were conducted (April 2013).

      Study Selection

      Randomized controlled trials of community-dwelling older adults, defined as frail according to physical function and physical difficulties in activities of daily living (ADL). Included trials had to compare an exercise intervention with a control or another exercise intervention, and assess performance-based measures of physical function such as mobility and gait, or disability in ADL.

      Data Extraction

      Two review authors independently screened the search results and performed data extraction and risk of bias assessment. Nineteen trials were included, 12 of them comparing exercise with an inactive control. Most exercise programs were multicomponent.

      Data Synthesis

      Meta-analysis was performed for the comparison of exercise versus control with the inverse variance method under the random-effects models. When compared with control interventions, exercise was shown to improve normal gait speed (mean difference [MD]=.07m/s; 95% confidence interval [CI], .04–.09), fast gait speed (MD=.08m/s; 95% CI, .02–.14), and the Short Physical Performance Battery (MD=2.18; 95% CI, 1.56–2.80). Results are inconclusive for endurance outcomes, and no consistent effect was observed on balance and the ADL functional mobility. The evidence comparing different modalities of exercise is scarce and heterogeneous.

      Conclusions

      Exercise has some benefits in frail older people, although uncertainty still exists with regard to which exercise characteristics (type, frequency, duration) are most effective.

      Keywords

      List of abbreviations:

      ADL (activities of daily living), BBS (Berg Balance Scale), CI (confidence interval), MD (mean difference), RCT (randomized controlled trial), SPPB (Short Physical Performance Battery), TUG (Timed Up and Go)
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      • Izquierdo M.
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      • van den Heuvel W.
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      • Cadore E.L.
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      • Izquierdo M.
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      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      applied a very broad definition of frailty that included both nonfrail and prefrail participants. The other 2 reviews
      • Chin A Paw M.J.
      • van Uffelen J.G.Z.
      • Riphagen I.
      • van Mechelen W.
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      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      applied consistent definitions of frailty but need to be updated with studies published recently in community-dwelling populations. The most recent reviews
      • Cadore E.L.
      • Rodríguez-Mañas L.
      • Sinclair A.
      • Izquierdo M.
      Effects of different exercise interventions on risk of falls, gait ability, and balance in physically frail older adults: a systematic review.
      • de Vries N.M.
      • van Ravensberg C.D.
      • Hobbelen J.S.
      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      did not identify some of the studies included in the present review, and both also included non–performance-based measures as main outcomes.
      This systematic review aims to integrate the most current evidence on the effect of exercise interventions on improving performance-based measures of physical function and markers of physical frailty in community-dwelling older people defined as frail according to physical function and physical difficulties in ADL. Specifically, we aimed to (1) examine the effectiveness of exercise compared with control interventions; (2) determine which exercise modalities are most effective; and (3) determine whether there are adverse effects within the exercise interventions.

      Methods

      We included randomized controlled trials (RCTs) evaluating the effect of physical exercise programs with or without other components on functional performance-based measures of physical function among community-dwelling, frail older adults. Inclusion criteria were as follows: participants should be (1) 65 years and older; (2) living in the community; and (3) defined as frail according to standardized criteria (eg, Fried's), or considered frail according to reduced physical function measured with physical performance scales (eg, Short Physical Performance Battery [SPPB]) or performance-based measures such as gait and mobility, muscle strength, nutritional intake, weight change, balance, endurance, fatigue, and physical activity. Participants either had to have limitations in 2 or more performance-based frailty measures or had to have clinically significant limitations in a single measure. Exclusion criteria were as follows: (1) inclusion of participants with disability (eg, advanced disability in performing ADL, dementia, or end-stage disease); (2) inclusion of prefrail participants (eg, those with nonsignificant impairment in frailty indicators); (3) inclusion of institutionalized participants; and (4) crossover design studies.
      Primary outcomes were performance-based measures of physical function such as mobility, gait, muscular strength, balance, endurance, and disability in ADL. Secondary outcomes were number of falls; institutionalization; adverse effects of the exercise program such as falls, fractures, tendinitis, or muscular soreness; health-related quality of life; symptoms of depression; hospitalization; and death.
      Searches were conducted in MEDLINE, The Cochrane Library, PEDro, and CINAHL databases (April 2013). All databases were searched using free text and descriptors. The search strategy was adapted for each database, including terms for frailty, older people, multiple expressions of exercise, and limiting for randomized controlled trial; the full search strategy is included in supplemental appendix S1 (available online only at http://www.archives-pmr.org/). The search results were treated using bibliographic management software (Biblioscape 7.41a), allowing for duplicate consolidation and further refining of the article list. In addition, reference lists from previous systematic reviews
      • Liu C.J.
      • Latham N.K.
      Progressive resistance strength training for improving physical function in older adults.
      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      • Howe T.E.
      • Rochester L.
      • Neil F.
      • Skelton D.A.
      • Ballinger C.
      Exercise for improving balance in older people.
      on exercise for the elderly were hand searched to identify trials on frail community-dwelling individuals. Two review authors (M.R., M.S., L.C., or M.G.) independently screened the search results and performed data extraction and risk of bias assessment. Any discrepancies were resolved by consensus or consulting with a third author.
      We used the tool for assessing risk of bias proposed by the Cochrane Collaboration.

      Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions version 5.1.0 [updated March 2011]. The Cochrane Collaboration: 2011. Available at: http://www.cochrane-handbook.org. Accessed March 21, 2013.

      For each trial, we assessed the risk of bias of the following domains: random sequence generation, allocation concealment, blinding of assessments, incomplete outcome data, and selective outcome reporting. For each trial, an overall assessment of risk of bias was derived as low, high, or unclear based on the previous assessments. If any domain was at high risk of bias, the trial was considered to be at high risk of bias. Trials with 4 or 5 domains at low risk of bias were considered to be at low risk of bias. Otherwise, risk of bias of the trial was considered to be unclear.
      We pooled data as presented in the original trials, either as intention to treat or not. Heterogeneity was assessed with the I2 statistic, considering values greater than 50% as a sign of relevant heterogeneity. The effect of treatment was estimated by mean differences (MDs) and standardized MDs in continuous outcomes and risk ratios in dichotomous outcomes. Pooled effect measures were computed applying the inverse-variance method in a random-effects model. Planned subgroup analyses on age and baseline performance, as well as sensitivity analyses with trials where frailty had been defined following Fried's criteria, could not be conducted because of the lack of detailed data and a low number of trials.

      Results

      A total of 38 citations providing data from 19 trials were included in this systematic review.
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      Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women.
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      • Leveille S.G.
      Are changes in leg power responsible for clinically meaningful improvements in mobility in older adults?.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
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      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Binder E.F.
      • Yarasheski K.E.
      • Steger-May K.
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      Effects of progressive resistance training on body composition in frail older adults: results of a randomized, controlled trial.
      • Ehsani A.A.
      • Spina R.J.
      • Peterson L.R.
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      Attenuation of cardiovascular adaptations to exercise in frail octogenarians.
      • Villareal D.T.
      • Steger-May K.
      • Schechtman K.B.
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      Effects of exercise training on bone mineral density in frail older women and men: a radomised controlled trial.
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      • Brown M.
      • Sinacore D.R.
      • Ehsani A.A.
      • Binder E.F.
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      • Kohrt W.M.
      Low-intensity exercise as a modifier of physical frailty in older adults.
      • de Jong N.
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      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      • de Jong N.
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      • de Graaf C.
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      Effect of dietary supplements and physical exercise on sensory perception, appetite, dietary intake and body weight in frail elderly subjects.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
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      • van Staveren W.A.
      Dietary supplements and physical exercise affecting bone and body composition in frail elderly persons.
      • de Jong N.
      Sensible aging: using nutrient-dense foods and physical exercise with the frail elderly.
      • de Jong N.
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      Nutrient-dense foods and exercise in frail elderly: effects on B vitamins, homocysteine, methylmalonic acid, and neuropsychological functioning.
      • Chin A Paw M.J.
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      Physical exercise and/or enriched foods for functional improvement in frail, independently living elderly: a randomized controlled trial.
      • Chin A Paw M.J.
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      • Gill T.M.
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      A prehabilitation program for physically frail community-living older persons.
      • Gill T.M.
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      A prehabilitation program for the prevention of functional decline: effect on higher level physical function.
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      Improved self-confidence was a mechanism of action in two geriatric trials evaluating physical interventions.
      • Giné-Garriga M.
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      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Hagedorn D.K.
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      Effects of traditional physical training and visual computer feedback training in frail elderly patients. A randomized intervention study.
      • Pollock R.D.
      • Martin F.C.
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      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      • Rejeski W.J.
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      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      • Rydwik E.
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      • Akner G.
      Effects of a physical and nutritional intervention program for frail elderly people over age 75. A randomized controlled pilot treatment trial.
      • Rydwik E.
      • Frandin K.
      • Akner G.
      Effects of a physical training and nutritional intervention program in frail elderly people regarding habitual physical activity level and activities of daily living—a randomized controlled pilot study.
      • Rydwik E.
      • Gustafsson T.
      • Frandin K.
      • Akner G.
      Effects of physical training on aerobic capacity in frail elderly people (75+ years). Influence of lung capacity, cardiovascular disease and medical drug treatment: a randomized controlled pilot trial.
      • Lammes E.
      • Rydwik E.
      • Akner G.
      Effects of nutritional intervention and physical training on energy intake, resting metabolic rate and body composition in frail elderly. A randomised, controlled pilot study.
      • Tousignant M.
      • Corriveau H.
      • Roy P.M.
      • Desrosiers J.
      • Dubuc N.
      • Hébert R.
      Efficacy of supervised Tai Chi exercises versus conventional physical therapy exercises in fall prevention for frail older adults: a randomized controlled trial.
      • Vestergaard S.
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      • Puggaard L.
      Home-based video exercise intervention for community-dwelling frail older women: a randomized controlled trial.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      • Watt J.R.
      • Jackson K.
      • Franz J.R.
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      • Evans J.
      • Kerrigan D.C.
      Effect of a supervised hip flexor stretching program on gait in frail elderly patients.
      • Westhoff M.H.
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      • Boshuizen H.C.
      Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people.
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      • Frederiksen H.
      • Bathum L.
      • Worm C.
      • Christensen K.
      • Puggaard L.
      ACE genotype and physical training effects: a randomized study among elderly Danes.
      The flow chart of references and the causes of exclusion are presented in figure 1. We faced some challenges in assessing inclusion criteria: we included trials whose participants had moderate dependence in mobility, but we excluded trials on participants with dependence in basic ADL.
      • Sato D.
      • Kaneda K.
      • Wakabayashi H.
      • Shimoyama Y.
      • Baba Y.
      • Nomura T.
      Comparison of once and twice weekly water exercise on various bodily functions in community-dwelling frail elderly requiring nursing care.
      • Szturm T.
      • Betker A.L.
      • Moussavi Z.
      • Desai A.
      • Goodman V.
      Effects of an interactive computer game exercise regimen on balance impairment in frail community-dwelling older adults: a randomized controlled trial.
      In 3 included trials,
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      it cannot be ruled out that a small percentage of participants had mild to moderate cognitive impairment. In the study by Boshuizen et al,
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      participants were excluded if they had a self-reported disease or condition that would be adversely affected by the exercises involved in the program, and in the study by de Jong et al,
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      reasons for dropout included (terminal) disease, but participants needed to have the ability to understand study procedures. In the aforementioned 2 studies, no clear cognitive condition is stated, so we assumed participants were not cognitively impaired. The mean baseline Mini-Mental State Examination scores in the study by Worm et al
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      were 23.9±4.1 and 23.5±5.2 in the exercise group and in the control group, respectively, so some participants included in the study could have had mild to moderate cognitive impairment.
      Twelve trials compared an exercise intervention with an inactive control, presented in table 1. The exercise interventions studied differed in content (resistance, stretching, strength, flexibility, balance), setting (facility/home), delivery (individual/group), duration, and frequency. The exercise interventions tested were combinations of aerobic, balance, flexibility, endurance, and strength exercises,
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      • Vestergaard S.
      • Kronborg C.
      • Puggaard L.
      Home-based video exercise intervention for community-dwelling frail older women: a randomized controlled trial.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      combinations of balance and strength exercises,
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Van Ness P.H.
      A prehabilitation program for the prevention of functional decline: effect on higher level physical function.
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Rydwik E.
      • Lammes E.
      • Frändin K.
      • Akner G.
      Effects of a physical and nutritional intervention program for frail elderly people over age 75. A randomized controlled pilot treatment trial.
      strength exercise programs,
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      • Westhoff M.H.
      • Stemmerik L.
      • Boshuizen H.C.
      Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people.
      a stretching intervention,
      • Watt J.R.
      • Jackson K.
      • Franz J.R.
      • Dicharry J.
      • Evans J.
      • Kerrigan D.C.
      Effect of a supervised hip flexor stretching program on gait in frail elderly patients.
      and finally activities related to maintain and improve performance in ADL.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      Table 1Description of studies comparing exercise versus control
      StudyN
      Number of randomized patients, which may differ from number of analyzed patients.
      Frailty CriteriaControlInterventionFrequency and DurationFollow-upPerformance and Safety OutcomesRoB
      Risk of bias categories: low risk (L), unknown risk (U), high risk (H).
      Boshuizen,
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      2005
      Two exercise arms grouped into a single intervention arm.
      72(1) Elders experiencing difficulty in getting up from a chair, and (2) maximum knee-extensor torque in both legs not superior to 87.5Nm (25-kg force).Control group received no training and was asked to remain habitually active.Strength exercises for the thigh muscles, with use of elastic bands. Individual SSs at a facility and home USs.

      Arm 1: 2 SSs + 1 US

      Arm 2: 1 SS + 2 USs
      60min 3 times a week for 10wkEOI, 6mo FUPGait speed, tandem test, step test, TUG, GARS scaleU
      de Jong,
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      • de Jong N.
      • Chin A Paw M.J.
      • de Graaf C.
      • van Staveren W.A.
      Effect of dietary supplements and physical exercise on sensory perception, appetite, dietary intake and body weight in frail elderly subjects.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • Hiddink G.J.
      • van Staveren W.A.
      Dietary supplements and physical exercise affecting bone and body composition in frail elderly persons.
      • de Jong N.
      Sensible aging: using nutrient-dense foods and physical exercise with the frail elderly.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • et al.
      Nutrient-dense foods and exercise in frail elderly: effects on B vitamins, homocysteine, methylmalonic acid, and neuropsychological functioning.
      • Chin A Paw M.J.
      • de Jong N.
      • Schouten E.G.
      • Hiddink G.J.
      • Kok F.J.
      Physical exercise and/or enriched foods for functional improvement in frail, independently living elderly: a randomized controlled trial.
      • Chin A Paw M.J.
      • de Jong N.
      • Schouten E.G.
      • van Staveren W.A.
      • Kok F.J.
      Physical exercise or micronutrient supplementation for the wellbeing of the frail elderly? A randomised controlled trial.
      • Chin A Paw M.J.
      • de Jong N.
      • Pallast E.G.
      • Kloek G.C.
      • Schouten E.G.
      • Kok F.J.
      Immunity in frail elderly: a randomized controlled trial of exercise and enriched foods.
      1999
      Four arms grouped in 1 comparison: exercise ± diet vs control ± diet.
      217(1) Individuals who require health care, such as home care or Meals-on-Wheels service; (2) age ≥70y; (3) no regular exercise; (4) BMI<25kg/m2 on the basis of self-reported weight and height or recent weight loss; (4) no use of multivitamin supplements; and (5) ability to understand the study procedures.Supervised social program for 90min biweekly. In the off week, they were visited at their homes. Subjects were asked not to engage in other exercise programs during the study period.Supervised group training to maintain or improve mobility and performance of daily activities. Exercises of moderate, gradually increasing intensity comprised walking, exercise-to-music routines, skills training, stretching, and relaxation activities.45min, twice a week, for 17wkEOIMobility score, gait speed, SPPB, fitness score, ADL score, self-care score, well-beingU
      Fairhall,
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      • Cameron I.D.
      • Fairhall N.
      • Langron C.
      • et al.
      A multifactorial interdisciplinary intervention reduces frailty in older people: randomized trial.
      2012
      241Adults ≥70y, with 3 or more of the CHS Frailty criteria: (1) slow gait speed, (2) weak grip strength, (3) exhaustion, (4) low energy expenditure, (5) weight loss.Usual care available to older residents of the Hornsby Ku-ring-gai area from their general practitioner and community services, which may include medical management of health conditions, allied health input, assessment of care needs, and provision of care.Multifactorial interdisciplinary intervention targeting the CHS frailty phenotype. Participants classified as having grip weakness, slow 4-m walk time, or low physical activity level received up to 10 home-based physiotherapy sessions and performed a targeted, goal-focused, home-based strength, balance, and endurance training regimen. Mobility aids and other equipment were recommended, if needed. For participants meeting the weight loss criterion, a clinical evaluation of nutritional intake at home was made, and home-delivered meals and nutritional supplementation were offered, if appropriate. Participants reporting exhaustion and a high score in the Geriatric Depression Scale score were referred to a psychiatrist or psychologist. If applicable, chronic disease management programs were put in place or reinforced, and medication adequacy and compliance were reviewed.45–60min, 3–5 weekly sessions. 10 physiotherapy sessions over 12moEOIGait speed, SPPB, mobility score, Barthel Index, Geriatric Depression Score, EQ-5D quality of lifeL
      Gill,
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Byers A.
      A program to prevent functional decline in physically frail, elderly persons who live at home.
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • et al.
      A prehabilitation program for physically frail community-living older persons.
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Van Ness P.H.
      A prehabilitation program for the prevention of functional decline: effect on higher level physical function.
      • Peduzzi P.
      • Guo Z.
      • Marottoli R.A.
      • Gill T.M.
      • Araujo K.
      • Allore H.G.
      Improved self-confidence was a mechanism of action in two geriatric trials evaluating physical interventions.
      2002
      188(1) Individuals who required >10s to perform a rapid gait test or (2) could not stand up from a seated position in a hardback chair with their arms folded.Educational program designed to provide attention and health education. Monthly visits for 6mo, followed by monthly follow-up telephone calls for 6 additional months.Home training program. Periodic assessments of mobility, balance, and environmental hazards by a physical therapist, followed by individually tailored interventions that target physical impairments. Progressive exercises could be proposed for ROM, balance (10min daily), and muscle conditioning with resistant elastic bands (30min, 3 times/wk).45–60min assessment visits, 16 visits in 6moEOI, 6 mo FUPFalls, death, fractures, adverse effectsU
      Giné-Garriga,
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      2010
      51Participants verifying 1 of the following: (1) required more than 10s to perform a rapid-gait test, or (2) could not stand up 5 times from a seated position in a hardback chair with their arms folded, or (3) categorized as frail by the exhaustion criterion.Control group subjects continued their routine daily activities and had weekly social meetings at the training facility, including four 60-min health education sessions.Functional circuit training program focused on functional balance and lower body strength-based. Supervised group sessions held at a facility.45min, twice a week for 12wkEOI, 6mo FUPGait speed, gait test, kick test, semitandem, 1-limb stand, standup test, modified TUG, Barthel Index, fractures, adverse effectsL
      Rejeski,
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      2008
      412(1) Summary score <10 on the SPPB, (2) ability to complete the 400-m walk test within 15min without sitting and without the use of an assistive device (including a cane) or the help of another person, and (3) sedentary lifestyle.Active control (successful aging) with group workshops on health topics and an instructor-led program (5–10min) of upper extremity stretching exercises. Weekly for 24wk, and monthly thereafter.Physical activity program combining aerobic activities, strength, balance, and flexibility exercises. Exercise training initially center-based transitioning to home-based exercise.

      Ten weekly closed-group counseling sessions that focus on physical activity and prevention of physical disability.
      60min, 1–3 times a week (facility, by study phase) + 1–5 times a week (home), for 12mo2y EOI400-m walk efficacy, death, hospitalization, adverse effectsL
      Rydwik,
      • Rydwik E.
      • Lammes E.
      • Frändin K.
      • Akner G.
      Effects of a physical and nutritional intervention program for frail elderly people over age 75. A randomized controlled pilot treatment trial.
      • Rydwik E.
      • Frandin K.
      • Akner G.
      Effects of a physical training and nutritional intervention program in frail elderly people regarding habitual physical activity level and activities of daily living—a randomized controlled pilot study.
      • Rydwik E.
      • Gustafsson T.
      • Frandin K.
      • Akner G.
      Effects of physical training on aerobic capacity in frail elderly people (75+ years). Influence of lung capacity, cardiovascular disease and medical drug treatment: a randomized controlled pilot trial.
      • Lammes E.
      • Rydwik E.
      • Akner G.
      Effects of nutritional intervention and physical training on energy intake, resting metabolic rate and body composition in frail elderly. A randomised, controlled pilot study.
      2008
      Four arms grouped in 1 comparison: exercise ± vitamin D vs control ± vitamin D.
      96(1) Unintentional weight loss >5% during the last 12mo and/or BMI <20kg/m2, (2) low PA level graded with a PA scale.General physical training advice to take walks 3 times per week for at least 20min, to use staircases instead of an elevator from time to time, and to do 30min of physical activity each day. General diet advice to eat 3 main courses and 2–3 between-meal snacks combined with fluid.Group training led by an instructor comprising aerobic, muscle strength, and balance (Qigong) for 12wk in a facility. Afterwards, home-based exercises for 6mo. Subjects were encouraged to perform Qigong, functional muscle strength training and to take regular walks several times per week.60min, twice a week for 12wk (facility)EOI, 6 and 21mo FUPLeg muscle strength, tandem, 1-limb stand, step test, TUG, death, hospitalizationH
      Vestergaard,
      • Vestergaard S.
      • Kronborg C.
      • Puggaard L.
      Home-based video exercise intervention for community-dwelling frail older women: a randomized controlled trial.
      2008
      63(1) Unable to get outdoors without a walking aid or help, and/or (2) score ≤3 mobility-tiredness scale; and (3) able to get out of bed/chair.Control group subjects were asked not to change their usual daily habits.Home-based training with exercises for flexibility, balance, strength using elastic bands (upper and lower extremities), aerobic.26min, 3 times a week for 5moEOIGait speed, SPPB, handgrip, biceps strength, semitandem, chair rise, mobility-tiredness score, EQ-5D, EQ-VASH
      Villareal,
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      2011
      Four arms analyzed in 2 comparisons: exercise vs control; exercise + diet vs control + diet.
      107Obese elders had to meet 2 of the following operational criteria: (1) modified PPT of 18–32; (2) Vo2peak of 11–18mL/kg/min; or (3) difficulty in performing 2 IADL or 1 BADL.Control group subjects did not receive advice to change their diet or activity habits and were prohibited from participating in any weight loss or exercise program. Received general information about a healthy diet in monthly visits with the staff.Physical therapist led group training combining aerobic, resistance, flexibility, and balance exercises.90min, 3 times a week for 12moEOI, 12mo FUPSF-36, gait speed, SPPB, total 1 RM, 1-limb stand, obstacle course, FSQ score, adverse effectsL
      Watt,
      • Watt J.R.
      • Jackson K.
      • Franz J.R.
      • Dicharry J.
      • Evans J.
      • Kerrigan D.C.
      Effect of a supervised hip flexor stretching program on gait in frail elderly patients.
      2011
      74(1) Individuals with a low IADL score (<3/5); (2) a major orthopedic diagnosis in the lower back, pelvis, or lower extremities since the age of 50y.Shoulder abductor stretching exercise performed at home. Participants were supervised twice each week by a rehabilitation clinician.Hip extension stretching exercise performed at home. Participants were supervised twice each week by a rehabilitation clinician.8min, daily for 10wkEOIGait speedH
      Westhoff,
      • Westhoff M.H.
      • Stemmerik L.
      • Boshuizen H.C.
      Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people.
      2000
      21(1) Elders experiencing difficulty in getting up from a chair, and (2) maximum knee-extensor torque in both legs not >87.5Nm (25-kg force).Control group received no training and was asked to remain habitually active.Strength exercises for the thigh muscles, with use of elastic bands.

      Two individual supervised sessions at a facility and 1 home session unsupervised.
      60min, 3 times a week for 10wkEOI, 6mo FUPGait speed, tandem, balance test, box stepping, GARS ADLU
      Worm,
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      • Frederiksen H.
      • Bathum L.
      • Worm C.
      • Christensen K.
      • Puggaard L.
      ACE genotype and physical training effects: a randomized study among elderly Danes.
      2001
      46(1) Elders aged >70y; and (2) living in their home; and (3) not able to leave their home unaided or without mobility aids.Control group was not involved in any intervention.Group-based training at a facility consisting of flexibility, aerobic, rhythm, balance, strength, and endurance. Home-based muscle and flexibility training.60min, twice a week (facility) + 5–8min daily (home), for 12wkEOISF-36, gait speed, shoulder abductors, BBS, step maximum speedU
      Abbreviations: BADL, basic activities of daily living; BMI, body mass index; CHS, Cardiovascular Health Study; EOI, end of intervention; EQ-5D, EuroQol quality-of-life scale; EQ-VAS, EuroQol visual analog scale; FSQ, Functional Status Questionnaire; FUP, follow-up after end of intervention; GARS, Global Assessment of Recent Stress; H, high risk; IADL, instrumental activities of daily living; L, low risk; PA, physical activity; PPT, Physical Performance Test; RM, repetition maximum; RoB, risk of bias; ROM, range of motion; SF-36, Medical Outcomes Study 36-Item Short-Form Health Survey; SS, supervised session; U, unknown risk; US, unsupervised session; Vo2peak, peak oxygen consumption.
      Number of randomized patients, which may differ from number of analyzed patients.
      Risk of bias categories: low risk (L), unknown risk (U), high risk (H).
      Two exercise arms grouped into a single intervention arm.
      § Four arms grouped in 1 comparison: exercise ± diet vs control ± diet.
      || Four arms grouped in 1 comparison: exercise ± vitamin D vs control ± vitamin D.
      Four arms analyzed in 2 comparisons: exercise vs control; exercise + diet vs control + diet.
      Seven trials compared different modalities of exercise, described in table 2. Of these, 2 trials
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Brown M.
      • Sinacore D.R.
      • Ehsani A.A.
      • Binder E.F.
      • Holloszy J.O.
      • Kohrt W.M.
      Low-intensity exercise as a modifier of physical frailty in older adults.
      compared facility-based with home-based exercise and could be assessed through meta-analysis. The other trials explored specific exercise modalities such as a progressive resistance-training program using weighted vests,
      • Bean J.F.
      • Herman S.
      • Kiely D.K.
      • et al.
      Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women.
      • Bean J.F.
      • Kiely D.K.
      • LaRose S.
      • O'Neill E.
      • Goldstein R.
      • Frontera W.R.
      Increased Velocity Exercise Specific to Task (InVEST) training vs. the National Institute on Aging's (NIA) strength training program: changes in limb power and mobility.
      the addition of visual computer feedback to balance training,
      • Hagedorn D.K.
      • Holm E.
      Effects of traditional physical training and visual computer feedback training in frail elderly patients. A randomized intervention study.
      combining whole-body vibration with exercise,
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      or performing Tai Chi.
      • Tousignant M.
      • Corriveau H.
      • Roy P.M.
      • Desrosiers J.
      • Dubuc N.
      • Hébert R.
      Efficacy of supervised Tai Chi exercises versus conventional physical therapy exercises in fall prevention for frail older adults: a randomized controlled trial.
      The results of these trials are described in the text.
      Table 2Description of studies comparing 2 types of exercise
      StudyN
      Number of randomized patients, which may differ from number of analyzed patients.
      Frailty CriteriaIntervention 1Intervention 2Frequency and DurationFollow-upPerformance and Safety OutcomesRoB
      Risk of bias categories: low risk (L), unknown risk (U), high risk (H).
      Bean,
      • Bean J.F.
      • Herman S.
      • Kiely D.K.
      • et al.
      Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women.
      2004
      21Individuals with SPPB scores between 4 and 10.Small-group supervised exercise sessions in a facility. Exercises addressed major muscle groups of the trunk and limbs, emphasizing task-specific movement patterns (InVEST). Progressive resistance program using a weighted vest.Supervised exercises at a facility consisting of slow-velocity, low-resistance exercises using body or limb weight for resistance.30min, 3 times a week for 12wkEOIGait test, SPPB, leg press power, unilateral stance, chair riseU
      Bean,
      • Bean J.F.
      • Kiely D.K.
      • LaRose S.
      • O'Neill E.
      • Goldstein R.
      • Frontera W.R.
      Increased Velocity Exercise Specific to Task (InVEST) training vs. the National Institute on Aging's (NIA) strength training program: changes in limb power and mobility.
      • Bean J.F.
      • Kiely D.K.
      • LaRose S.
      • Goldstein R.
      • Frontera W.R.
      • Leveille S.G.
      Are changes in leg power responsible for clinically meaningful improvements in mobility in older adults?.
      2009
      138Individuals with SPPB scores between 4 and 10 who were able to climb a flight of stairs independently or using a device (eg, cane).Small-group supervised exercise sessions in a facility. Exercises addressed major muscle groups of the trunk and limbs, emphasizing task-specific movement patterns (InVEST). Progressive resistance program using a weighted vest.Small-group supervised exercise sessions in a facility. Exercises followed the National Institute on Aging training program. Resistance program using free weights.45–60min, 3 times a week for 16wkEOISPPB, Late Life Function Disability InstrumentU
      Binder,
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Binder E.F.
      • Yarasheski K.E.
      • Steger-May K.
      • et al.
      Effects of progressive resistance training on body composition in frail older adults: results of a randomized, controlled trial.
      • Ehsani A.A.
      • Spina R.J.
      • Peterson L.R.
      • et al.
      Attenuation of cardiovascular adaptations to exercise in frail octogenarians.
      • Villareal D.T.
      • Steger-May K.
      • Schechtman K.B.
      • et al.
      Effects of exercise training on bone mineral density in frail older women and men: a radomised controlled trial.
      2002
      119Individuals had to meet at least 2 of the following 3 criteria: (1) score between 18 and 32 on the modified PPT, (2) report of difficulty or need for assistance with up to 2 IADL or 1 ADL, or (3) achievement of a Vo2peak between 10 and 18mL/(kg
      Number of randomized patients, which may differ from number of analyzed patients.
      min).
      Facility-supervised exercise program 3 times a week. 1st phase: in group format, focused on flexibility, balance, coordination, speed of reaction, and strength. 2nd phase: progressive resistance training. 3rd phase: endurance training.Home exercise program comprising 9 activities that challenge flexibility, 2–3 times a week plus a monthly exercise class at a facility.9moEOISPPB, 1-limb stand, BBS, Functional Status ScaleL
      Brown,
      • Brown M.
      • Sinacore D.R.
      • Ehsani A.A.
      • Binder E.F.
      • Holloszy J.O.
      • Kohrt W.M.
      Low-intensity exercise as a modifier of physical frailty in older adults.
      2000
      84Participants had to score <32 points on the PPT.Supervised exercise program designed to challenge all major muscle

      groups and to enhance flexibility, balance, body handling skills, speed of reaction, coordination, and

      strength. 22 exercises with 3 levels of difficulty, 3 times a week for 36 sessions (about 3mo).
      Home exercise performing 9 activities that challenge range of motion. Participants were invited to exercise onsite under supervision once a month.About 3moEOIGait speed, SPPB, tandem, semitandem test, 1-limb stand, BBS, reach testU
      Hagedorn,
      • Hagedorn D.K.
      • Holm E.
      Effects of traditional physical training and visual computer feedback training in frail elderly patients. A randomized intervention study.
      2010
      35Patients referred to a falls and balance clinic. (1) Dynamic Gait Index score <19, (2) able to see visual feedback pictures, and (3) able to follow instructions for testing and training.Computer feedback balance training plus progressive resistance muscle strength, and physical fitness training. Balance training where participant controlled a computer game on the screen through weight shifts. Individual training held at a facility.Traditional balance training plus progressive resistance muscle strength and physical fitness training. Balance training on different surfaces with open and closed eyes. One legged balance training, walking on a line, passing an obstacle course. Individual training held at a facility.90min, twice a week for 12wkEOIGait test, tandem, 1-limb stand, BBS, balance test, raise test, 6-min walk test, Fall-Efficacy ScaleH
      Pollock,
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      2012
      78(1) Participants had 2 or more falls in the last 12mo or (2) 1 fall plus TUG test of >15s.Vibration group: whole-body vibration therapy session after each exercise session, consisting in 5×1-min bouts, separated by 30s of rest, on an asynchronous whole-body vibration platform. Frequency and amplitude up to 30Hz and 8-mm peak to peak.Exercise group: supervised exercise program at a facility, focused on progressive strength, balance, and functional mobility training.60min, 3 times a week for 8wkEOI, 4mo FUPSF-12, gait speed, BBS, TUG, fear of falling scoreU
      Tousignant,
      • Tousignant M.
      • Corriveau H.
      • Roy P.M.
      • Desrosiers J.
      • Dubuc N.
      • Hébert R.
      Efficacy of supervised Tai Chi exercises versus conventional physical therapy exercises in fall prevention for frail older adults: a randomized controlled trial.
      2012
      People requiring a minimum of 3 services (ie, occupational therapy, physiotherapy, neuropsychology, nursing, or physician) and (1) referred for a recent fall problem, and (2) identified as being at high risk of fall (BBS≤49/56 and at least 1 accidental fall in the previous 6mo).Supervised Tai Chi:

      movements that included a combination of body alignment and specific orientations, weight transfer, and changes of direction.
      Conventional physiotherapy: balance program that consisted of weight transfer, strengthening, and walking exercises.60min, twice a week for 15wkEOIFalls, number of fallsU
      Abbreviations: EOI, end of intervention; FUP, follow-up after end of intervention; H, high risk; IADL, instrumental activities of daily living; InVEST, Increased Velocity Exercise Specific to Task; L, low risk; PPT, Physical Performance Test; RoB, risk of bias; SF-12, 12-Item Short-Form Health Survey; U, unknown risk; Vo2peak, peak oxygen consumption.
      Number of randomized patients, which may differ from number of analyzed patients.
      Risk of bias categories: low risk (L), unknown risk (U), high risk (H).
      Definitions of frailty used in the trials were often not explicit and when so, they were quite diverse. All trials assessed outcomes at the end of the intervention, and only 5 trials reported longer follow-up data at 6 to 12 months. Overall risk of bias was low in 5 trials.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      The rest of the trials had an unknown or a high risk of bias.
      Trials with a 4-arm design
      • Rydwik E.
      • Frandin K.
      • Akner G.
      Effects of a physical training and nutritional intervention program in frail elderly people regarding habitual physical activity level and activities of daily living—a randomized controlled pilot study.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      had their data analyzed by pairing treatment arms (comparing exercise plus diet, with diet and exercise with control). A 2×2 factorial trial
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      testing exercise and a diet intervention presented its data combined into a comparison of exercise versus control. In a trial
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      of 2 exercise arms and 1 control arm, the exercise arms were combined.
      According to the methodological quality of the included trials, 5 studies showed a low risk of bias, 4 showed a high risk of bias, and 10 reported an unknown risk of bias (see tables 1 and 2).

       Effects of interventions

      Results for exercise compared with a control intervention at the end of treatment (12 trials) are presented in figures 2 through 4, and in supplemental appendix S2 (available online only at http://www.archives-pmr.org/). Exercise showed a significant and homogeneous effect on gait speed (see fig 2). Exercising participants walked faster than control participants, with a gait speed that on average was .06m/s higher for normal gait (95% confidence interval [CI], .04–.08) and .08m/s higher for fast gait speed (95% CI, .02–.14). Exercise also had a significant benefit on gait test results, decreasing in 1.73 seconds the time needed to walk 10m (95% CI, .26–3.20; I2=48%) (see supplemental fig S1, located in supplemental appendix S2). Gait speed refers to a test that requires the individual to walk a certain distance (eg, 8m) in a comfortable fast pace, to derive the gait speed in meters per second. The gait test includes, for example, the rapid gait test, which requires the subject to walk a shorter distance (eg, 3m), turn, and return to the initial position; the latest test is more related to general mobility and is usually assessed with seconds needed to perform the test.
      Figure thumbnail gr2
      Fig 2Gait results of exercise compared with control. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Figure thumbnail gr3
      Fig 3Combined performance results of exercise compared with control. Note that De Jong results have been rescaled from 0 to 16 (16 worse result) to 0 to 100. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Figure thumbnail gr4
      Fig 4Balance results of exercise compared with control. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Exercise significantly increased the performance measure SPPB by 1.87 units (95% CI, 1.17–2.57), although no differences were observed in general physical function scales or the Timed Up and Go (TUG) test, both measures showing heterogeneity (I2=61% and 72%, respectively) (see fig 3).
      Exercise did not prove to have a consistent effect on balance measures (see fig 4). Results for tandem and 1-limb tests were not significant albeit highly heterogeneous, while the semitandem test showed a significant increase of 2.93 seconds in the exercise group (95% CI, 1.24–4.62). The Berg Balance Scale (BBS) showed a significant increase of 17.40 points on a single trial (95% CI, 7.76–27.04).
      A significant effect of exercise in endurance was observed on the chair rise test, reducing the time needed to stand up 5 times by 2.35 seconds (95% CI, .35–4.35) (see supplemental fig S2, located in supplemental appendix S2).
      Functional mobility was assessed through different scales of dependence on ADL activities, and no significant effect of exercise was observed (standardized MD=.39; 95% CI, .07–.71; I2=67%) (see supplemental fig S3, located in supplemental appendix S2). In particular, the only trial
      • Chin A Paw M.J.
      • de Jong N.
      • Schouten E.G.
      • Hiddink G.J.
      • Kok F.J.
      Physical exercise and/or enriched foods for functional improvement in frail, independently living elderly: a randomized controlled trial.
      focused on maintaining and improving ADL failed to show a significant effect of exercise on a disability score that included self-rated disabilities in 16 daily activities, a mobility score as the sum of 4 items (such as move outdoors, use stairs, and walk at least 400m), and a self-care ability score as the sum of 7 items (such as walk between rooms, use the toilet, and get dressed).
      Only 7 trials presented data on adverse effects related to exercise (see supplemental fig S4, located in supplemental appendix S2). The frequency and characteristics of the adverse effects depended on the type of exercise tested and the setting, either home-based or facility-based. In a facility-based trial
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      aiming to improve balance and strength, no cases of fractures or muscular soreness were observed, and only 1 case of tendinitis occurred. In a second facility-based trial
      • Lammes E.
      • Rydwik E.
      • Akner G.
      Effects of nutritional intervention and physical training on energy intake, resting metabolic rate and body composition in frail elderly. A randomised, controlled pilot study.
      combining aerobic, resistance, flexibility, and balance exercises, only 1 case of fractures and tendinitis was observed, and 4% of participants fell. The 3 home-based trials
      • Chin A Paw M.J.
      • de Jong N.
      • Schouten E.G.
      • van Staveren W.A.
      • Kok F.J.
      Physical exercise or micronutrient supplementation for the wellbeing of the frail elderly? A randomised controlled trial.
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      presented higher overall incidences of adverse effects. In a trial
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      testing an exercise intervention to improve endurance, strength, and flexibility that was initially center-based and later transitioned to home-based, the overall incidence of muscular soreness was 81.60%. In a trial
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Byers A.
      A program to prevent functional decline in physically frail, elderly persons who live at home.
      testing a multimodal intervention with competency-based exercises, overall incidences of fractures, musculoskeletal problems leading to restriction in usual activities, and falls were 3.26%, 31.5%, and 56.5%, respectively. In the last trial
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      testing a multifactorial intervention targeting the Cardiovascular Health Study frailty phenotype, the incidence of back pain was 1%. None of the included trials reported adverse effects such as institutionalization or hospitalization. There were no significant differences between intervention and control in any of the trials. Graphic results for endurance, functional mobility, and adverse effects are shown in supplemental appendix S2.
      Seven studies compared different types of exercise and did not show a consistent effect of any of them on performance measures. Supervised facility-based programs of variable composition and intensity were compared with home-based, unsupervised flexibility exercises.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Brown M.
      • Sinacore D.R.
      • Ehsani A.A.
      • Binder E.F.
      • Holloszy J.O.
      • Kohrt W.M.
      Low-intensity exercise as a modifier of physical frailty in older adults.
      Benefits were observed for some measures (eg, SPPB, Physical Performance Test, ADL disability) in the more intense programs compared with flexibility exercises in 175 participants.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Brown M.
      • Sinacore D.R.
      • Ehsani A.A.
      • Binder E.F.
      • Holloszy J.O.
      • Kohrt W.M.
      Low-intensity exercise as a modifier of physical frailty in older adults.
      A progressive resistance-training program using weighted vests for resistance (InVest) failed to show a significant effect in performance measures (eg, SPPB, chair stand), either a slow-velocity low-resistance program
      • Bean J.F.
      • Herman S.
      • Kiely D.K.
      • et al.
      Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women.
      or the National Institute on Aging's strength-training program.
      • Bean J.F.
      • Kiely D.K.
      • LaRose S.
      • O'Neill E.
      • Goldstein R.
      • Frontera W.R.
      Increased Velocity Exercise Specific to Task (InVEST) training vs. the National Institute on Aging's (NIA) strength training program: changes in limb power and mobility.
      Balance training using visual computer feedback did not have an effect on performance measures (eg, TUG test, BBS, 6-min walk test) compared with conventional balance training.
      • Hagedorn D.K.
      • Holm E.
      Effects of traditional physical training and visual computer feedback training in frail elderly patients. A randomized intervention study.
      The addition of whole-body vibration to strength and balance exercises failed to show an effect on performance measures (eg, TUG test, BBS).
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      Performing Tai Chi significantly reduced the risk of falling compared with conventional physiotherapy (risk ratio, .74; 95% CI, .56–.98), although the mean number of falls was not different in both groups.
      • Tousignant M.
      • Corriveau H.
      • Roy P.M.
      • Desrosiers J.
      • Dubuc N.
      • Hébert R.
      Efficacy of supervised Tai Chi exercises versus conventional physical therapy exercises in fall prevention for frail older adults: a randomized controlled trial.
      There is scarce evidence available on the effect of exercise past the end of the intervention, and suggests that its benefits are short-lived when exercise is discontinued.
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      • Rydwik E.
      • Lammes E.
      • Frändin K.
      • Akner G.
      Effects of a physical and nutritional intervention program for frail elderly people over age 75. A randomized controlled pilot treatment trial.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      • Westhoff M.H.
      • Stemmerik L.
      • Boshuizen H.C.
      Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people.
      Nevertheless, there is a significant effect on fast gait speed between 6 and 12 months after discontinuing exercise compared with control (pooled results from 3 trials
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Rydwik E.
      • Lammes E.
      • Frändin K.
      • Akner G.
      Effects of a physical and nutritional intervention program for frail elderly people over age 75. A randomized controlled pilot treatment trial.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      not shown), as well as a significant effect on SPPB.
      • Villareal D.T.
      • Chode S.
      • Parimi N.
      • et al.
      Weight loss, exercise, or both and physical function in obese older adults.
      The effect on balance, endurance, and functional status dissipates. From the limited evidence comparing different types of exercises at follow-up, similar conclusions can be derived on the dissipation of effect once the exercise is discontinued.
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.

      Discussion

      This systematic review has identified the available evidence on the effect of exercise in frail elderly people. When compared with control interventions, exercise has shown to improve gait speed and the SPPB in the frail elderly.
      Results are inconclusive for endurance outcomes, and no consistent effect was observed on balance and functional status. The evidence comparing different modalities of exercise is scarce, and it is not possible to pinpoint which exercise characteristics (type, frequency, intensity, duration, setting, combinations) are most effective. Most of the trials included in the review have an unclear or a high risk of bias in their results.
      The strong points of this project are as follows: (1) its specific focus on a well-defined population (community-dwelling frail elderly excluding prefrail individuals); (2) its restrictive inclusion of RCTs; (3) the inclusiveness of all types of physical activity interventions and comparisons; and (4) the robust outcomes assessed (performance outcomes), which are relevant indicators of disability for rehabilitation and geriatric specialists. We have focused on frail older adults without dementia and dependency, because this is a population in whom prevention of disability through physical activity is likely. For this reason we have excluded hospitalized and institutionalized individuals, more likely to be dependent or in an unstable clinical condition, and in whom prevention of disability requires further attention. Prefrail individuals were also excluded because different types of exercise programs should be applied.
      There are several systematic reviews published on the benefits of physical activity in older adults; however, to our knowledge, there are only 6 systematic reviews
      • Chin A Paw M.J.
      • van Uffelen J.G.Z.
      • Riphagen I.
      • van Mechelen W.
      The functional effects of physical exercise training in frail older people: a systematic review.
      • Daniels R.
      • van Rossum E.
      • de Witte L.
      • Kempen G.I.
      • van den Heuvel W.
      Interventions to prevent disability in frail community-dwelling elderly: a systematic review.
      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      • Cadore E.L.
      • Rodríguez-Mañas L.
      • Sinclair A.
      • Izquierdo M.
      Effects of different exercise interventions on risk of falls, gait ability, and balance in physically frail older adults: a systematic review.
      • de Vries N.M.
      • van Ravensberg C.D.
      • Hobbelen J.S.
      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      published specifically on the benefits of exercise in frail older adults.
      Our review provides an up-to-date search and quantifies the effect of exercise on different performance parameters through meta-analysis. Without regular updates, systematic reviews become outdated quickly, especially in areas of science with many active researchers.
      • Dijkers M.P.
      • Bushnik T.
      • Heinemann A.W.
      • et al.
      Systematic reviews for informing rehabilitation practice: an introduction.
      Of the 6 previous systematic reviews, only 2
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      • de Vries N.M.
      • van Ravensberg C.D.
      • Hobbelen J.S.
      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      performed a meta-analysis. De Vries et al
      • de Vries N.M.
      • van Ravensberg C.D.
      • Hobbelen J.S.
      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      could not use weighted MDs in their analysis because of the large variation and the large number of studies that did not report sufficient data; therefore, some of the analysis was based on only a few studies and small samples, resulting in inconclusive CIs. Chou et al
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      also performed a meta-analysis but used a broad definition of frailty that could have included nonfrail and prefrail participants.
      Chin A Paw et al
      • Chin A Paw M.J.
      • van Uffelen J.G.Z.
      • Riphagen I.
      • van Mechelen W.
      The functional effects of physical exercise training in frail older people: a systematic review.
      examined the effect of exercise on the functional ability of frail older adults. They included all studies that were published between 1995 and 2007, considering any setting and using at least 1 performance-based measure of physical function. No standardized definition of frail was considered, and the included trials presented a variable range of functional abilities. From a qualitative assessment of the trials, the authors concluded that regular exercise training (resistance and multicomponent training) could improve functional outcomes in this population, although more high-quality studies were needed.
      Daniels et al
      • Daniels R.
      • van Rossum E.
      • de Witte L.
      • Kempen G.I.
      • van den Heuvel W.
      Interventions to prevent disability in frail community-dwelling elderly: a systematic review.
      examined the effect of any type of intervention on disability in community-dwelling, physically frail older adults. The review included studies verifying at least 1 of the frailty indicators described by Ferrucci et al
      • Ferrucci L.
      • Guralnik J.M.
      • Studenski S.
      • et al.
      Designing randomized controlled trials aimed at preventing or delaying functional decline and disability in frail older persons: a consensus report.
      to identify their participants as frail but focused solely on the outcome disability. Since frailty is thought to be caused by multisystem reduction, the presence of only 1 frailty indicator does not necessarily warrant that participants were frail. With our more strict frailty criteria, only 5
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Byers A.
      A program to prevent functional decline in physically frail, elderly persons who live at home.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      of the 10 studies in Daniels were included in our review. The authors suggested that multicomponent exercise training reduced disability impact, especially in moderately frail people. Nevertheless, the subset of trials verifying our more strict frailty criteria
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Byers A.
      A program to prevent functional decline in physically frail, elderly persons who live at home.
      • Binder E.F.
      • Schechtman K.B.
      • Ehsani A.A.
      • et al.
      Effects of exercise training on frailty in community-dwelling older adults: results of a randomized, controlled trial.
      • Boshuizen H.C.
      • Stemmerik L.
      • Westhoff M.H.
      • Hopman-Rock M.
      The effects of physical therapists' guidance on improvement in a strength-training program for the frail elderly.
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      • Worm C.H.
      • Vad E.
      • Puggaard L.
      • Stivring H.
      • Lauritsen J.
      • Kragstrup J.
      Effects of a multicomponent exercise program on functional ability in community-dwelling, frail older adults.
      showed conflicting results with regard to prevention of disability, and this result is in agreement with the uncertainty identified in our review and in a more general overview.
      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      Particularly relevant is that the only included trial
      • de Jong N.
      • Chin A Paw M.J.
      • de Groot L.C.
      • de Graaf C.
      • Kok F.J.
      • van Staveren W.A.
      Functional biochemical and nutrient indices in frail elderly people are partly affected by dietary supplements but not by exercise.
      that focused on maintaining and improving ADL in community-dwelling frail individuals failed to show a significant effect of exercise on a disability score.
      In a qualitative overview, Theou et al
      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      examined the effectiveness of current exercise interventions for the management of frailty. The authors included frail subjects who were community dwelling, in retirement homes and mixed settings, in the hospital, and in long-term care. The authors found that only 3 trials used a validated definition of frailty to categorize participants, while the rest of the trials either used a nonvalidated definition or did not include an operational definition of frailty. This key finding that limits the applicability of its results shows the urgent need for a clear and widely accepted definition of frailty. Despite these limitations, the authors pointed out some characteristics of exercise programs that seemed to show superior outcomes: multicomponent training with a duration of ≥5 months and performed 3 times per week for 30 to 45 minutes per session. Nevertheless, the applicability of these conclusions is limited given the broad spectrum of participants' settings and interventions considered, the limitations in frailty definition observed, and the qualitative nature of the comparisons performed. Further evidence from specific randomized trials or providing a meta-analysis is necessary to confirm these conclusions.
      Chou
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      performed a meta-analysis that aimed to determine the effect of exercise on the physical function, ADL, and quality of life of frail older adults living in the community or institutionalized. Their inclusion criterion for frailty was based on the Fried Frailty Index, Speechley and Tinetti's criteria, and the Falls Efficacy Scale, with a very broad perspective that could have included nonfrail or prefrail participants as well as dependent participants who are past the frailty predisability stage. Regardless of including studies published between 2001 and June 2010, they did not include most trials in Theou's review.
      • Theou O.
      • Stathokostas L.
      • Roland K.P.
      • et al.
      The effectiveness of exercise interventions for the management of frailty: a systematic review.
      The results of their meta-analysis on community and noncommunity trials agree with our findings, showing a significant benefit of exercise in gait speed (their results show an improvement of .07m/s, and our results show an improvement of .06m/s) and BBS, but also great heterogeneity in results for the TUG test and performance in ADL.
      De Vries et al
      • de Vries N.M.
      • van Ravensberg C.D.
      • Hobbelen J.S.
      • Olde Rikkert M.G.
      • Staal J.B.
      • Nijhuis-van der Sanden M.W.
      Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis.
      also performed a meta-analysis that aimed to assess the effects of physical exercise therapy on physical functioning, mobility, physical activity, and quality of life. Meta-analysis limitations of this trial have been previously discussed. Their inclusion criterion for frailty was based on the presence of mobility problems, physical disability, multimorbidity, or a combination of these, so that nonfrail or prefrail participants could have been included. They found that physical exercise therapy had a positive effect on mobility and physical functioning. High-intensity exercise interventions seem to be more effective in improving physical functioning than low-intensity exercise interventions.
      Cadore et al
      • Cadore E.L.
      • Rodríguez-Mañas L.
      • Sinclair A.
      • Izquierdo M.
      Effects of different exercise interventions on risk of falls, gait ability, and balance in physically frail older adults: a systematic review.
      aimed to recommend training strategies that improve the functional capacity in physically frail older adults, focusing specially on supervised exercise programs that improve muscle strength, fall risk, balance, and gait ability. They showed that multicomponent exercise intervention seemed to be the best strategy to improve the rate of falls, gait ability, balance, and strength performance in physically frail older individuals. They included studies that defined subjects as prefrail and mild-to-moderate frail, and there were no restriction to RCTs.
      Our systematic review is in agreement with the systematic reviews cited in that the most studied exercise protocol for frail older adults is a multicomponent training. We have found moderate evidence to support exercise training for improving gait speed and combined performance measures such as SPPB, in line with other authors,
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      but we have found the evidence to be inconclusive regarding the effect of exercise training for improving functional mobility or balance, in contrast to other reviews.
      • Daniels R.
      • van Rossum E.
      • de Witte L.
      • Kempen G.I.
      • van den Heuvel W.
      Interventions to prevent disability in frail community-dwelling elderly: a systematic review.
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      In our systematic review, exercise has shown to improve gait speed and performance in the frail elderly, which is similar to Chou's findings.
      • Chou C.H.
      • Hwang C.L.
      • Wu Y.T.
      Effect of exercise on physical function, daily living activities, and quality of life in the frail older adults: a meta-analysis.
      Gait speed slower than .60m/s was a common feature in the frail older adults.
      • Peterson M.J.
      • Giuliani C.
      • Morey M.C.
      • et al.
      Physical activity as a preventative factor for frailty: the Health, Aging, and Body Composition Study.
      Additionally, slowed gait speed in the older adult population has been related to an increased risk for falls,
      • Bootsma-van der Wiel A.
      • Gussekloo J.
      • De Craen A.J.
      • Van Exel E.
      • Bloem B.R.
      • Westendorp R.G.
      Common chronic diseases and general impairments as determinants of walking disability in the oldest-old population.
      which, in turn, often leads to a loss of independent living and to institutionalization. As an outcome measure, gait speed has been shown to be a predictor of functional decline, nursing home placement, and mortality.
      • Brach J.S.
      • Van Swearingen J.M.
      • Newman A.B.
      • Kriska A.M.
      Identifying early decline in physical function in community-dwelling older women: performance-based and self-report measures.
      Specifically, a decrease in gait speed of 0.1m/s has been associated with a 10% decrease in the ability to perform instrumental ADL.
      • Judge J.O.
      • Schechtman K.
      • Cress E.
      The relationship between physical performance measures and independence in instrumental activities of daily living.
      Reduced muscle strength or poor balance results in a decrease in gait speed. Exercise training has shown to increase gait speed; thus, frail older adults might improve in ambulation and require less dependence and assistance in performing ADL. Clinical practice guidelines explicitly recommend lower limb strength exercises and balance training to prevent falls. Gait speed and performance should also be considered.
      • Gillespie L.
      • Robertson M.
      • Gillespie W.
      • et al.
      Interventions for preventing falls in older people living in the community.
      Improvements in balance and functional mobility might be linked to the exercise program characteristics. Despite the lack of clear evidence of the effect of exercise on ADL, there is an argument for task-oriented or functional practice. Previous studies
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Skelton D.A.
      • Young A.
      • Greig C.A.
      • Malbut K.E.
      Effects of resistance training on strength, power, and selected functional abilities of women aged 75 and older.
      have shown the importance of the exercise being task specific if functional ability is to be improved. The duration of training has also been suggested to be an important contributing factor to the retention of neuromuscular adaptations once training has ended,
      • Smith K.
      • Winegard K.
      • Hicks A.L.
      • McCartney N.
      Two years of resistance training in older men and women: the effects of three years of detraining on the retention of dynamic strength.
      so longer-duration programs might be recommended.
      Some authors argue that the number of adverse events is minimal and rarely life threatening, while the gains of regular exercise clearly outweigh the risks.
      • Gill T.M.
      • Baker D.I.
      • Gottschalk M.
      • Peduzzi P.N.
      • Allore H.
      • Byers A.
      A program to prevent functional decline in physically frail, elderly persons who live at home.
      • Chin A Paw M.J.
      • de Jong N.
      • Schouten E.G.
      • van Staveren W.A.
      • Kok F.J.
      Physical exercise or micronutrient supplementation for the wellbeing of the frail elderly? A randomised controlled trial.
      • Fairhall N.
      • Sherrington C.
      • Kurrle S.E.
      • Lord S.R.
      • Lockwood K.
      • Cameron I.D.
      Effect of a multifactorial interdisciplinary intervention on mobility-related disability in frail older people: randomised controlled trial.
      • Giné-Garriga M.
      • Guerra M.
      • Pagès E.
      • Manini T.M.
      • Jiménez R.
      • Unnithan V.B.
      The effect of functional circuit training on physical frailty in frail older adults: a randomized controlled trial.
      • Pollock R.D.
      • Martin F.C.
      • Newham D.J.
      Whole-body vibration in addition to strength and balance exercise for falls-related functional mobility of frail older adults: a single-blind randomized controlled trial.
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      • Lammes E.
      • Rydwik E.
      • Akner G.
      Effects of nutritional intervention and physical training on energy intake, resting metabolic rate and body composition in frail elderly. A randomised, controlled pilot study.
      However, depending on the exercise type, we have found that some important adverse events have been detected, such as fractures or falls. Soreness had been reported as an adverse effect in different trials
      • Rejeski W.J.
      • King A.C.
      • Katula J.A.
      • et al.
      Physical activity in prefrail older adults: confidence and satisfaction related to physical function.
      ; however, soreness is a normal consequence of the training process in this population. Therefore, exercise programs should be well designed, and conducted and monitored by well-trained physiotherapists and physical activity specialists. Moreover, trials should systematically report adverse effects (eg, type, when does it appear and disappear, its severity, and whether it causes a hospitalization). This register could allow future assessments on the risk-benefit of the intervention.
      While more research is still needed, most evidence shows that regular physical activity or exercise is beneficial for older adults who are frail or at high risk of frailty. Rehabilitation and physical activity specialists should recommend regular physical activity or exercise training to frail older adults as a means to modify frailty and its adverse outcomes.
      • Walston J.
      • Hadley E.C.
      • Ferrucci L.
      • et al.
      Research agenda for frailty in older adults: toward a better understanding of physiology and etiology: summary from the American Geriatrics Society/National Institute on Aging Research Conference on Frailty in Older Adults.
      However, the exercise recommendations for a healthy older adult will likely be different from those targeting frail older adults. Specifically, frail older adults may need functional-based exercise programs with shorter-duration sessions compared with healthy older adults. Physical activity programs linked to local community facilities offering exercise programs for older adults could offer some advantages over home-based programs, facilitating the continuity of a functional-based exercise program linked or not to social activities, but they have other disadvantages in terms of costs, difficulties in transport and comfort, and preferences of users.
      With increasing age, there is a well-described decline in voluntary physical activity leading to an increase risk of frailty.
      • Walston J.
      • Hadley E.C.
      • Ferrucci L.
      • et al.
      Research agenda for frailty in older adults: toward a better understanding of physiology and etiology: summary from the American Geriatrics Society/National Institute on Aging Research Conference on Frailty in Older Adults.
      In the present systematic review, we have restricted the inclusion criteria to individuals older than 65 years. Liu and Fielding
      • Liu C.K.
      • Fielding R.A.
      Exercise as an intervention for frailty.
      reviewed the literature investigating the utility of aerobic and resistance exercise training as an intervention for frailty in older adults. The authors concluded that gains of regular exercise clearly outweigh its risks (mainly musculoskeletal complaints, rare cases of falls and cardiovascular risks) if the exercise is appropriately designed. According to our results, there is little evidence to guide interventions to prevent or reduce functional mobility and mobility-related disability in frail older people. The optimal intervention to improve these parameters in daily situations remains unclear. Studies should also follow Consolidated Standards of Reporting Trials (CONSORT) recommendations for nonpharmacologic trials
      • Boutron I.
      • Moher D.
      • Altman D.G.
      • Schulz K.F.
      • Ravaud P.
      CONSORT Group. Extending the CONSORT statement to randomized trials of nonpharmacologic treatment: explanation and elaboration.
      to report risk of bias with a total transparency, and make effective interventions reproducible in the clinical practice.
      Moreover, several related areas need further investigation. Adherence to an exercise regimen is necessary to observe beneficial effects, and strategies to increase adherence need to be developed in order to effectively implement exercise as a treatment modality on a wide scale. Also, more studies should assess the sustainability of the effects of exercise. In future studies, researchers should also assess whether significant results translate into significant benefits in clinical practice.

       Study limitations

      Regarding the project's limitations, one common finding in the present review is the variability in participant and intervention characteristics, and outcome measures used across studies, similar to previous reviews. Given the multisystem nature of frailty, this variability is to be expected, since multicomponent interventions need to be proposed to affect different indicators of frailty, which will need to be assessed with different outcome measures. Nevertheless, this great heterogeneity hinders the ability to draw conclusions about the appropriate design of the exercise program and, to some extent, the ability to quantify the effect of exercise interventions. Additional limitations of the project are the sample sizes and the risk of bias of the trials included in the review, which limit the strength of the conclusions drawn. In the future, it would be desirable to have larger trials with more rigorous methodology conducted to provide more robust evidence on this topic.

      Conclusions

      Exercise has some benefits in frail older people, although uncertainty still exists with regard to which exercise characteristics (type, frequency, intensity, duration, setting, combinations) are most effective. When compared with control interventions, exercise has shown to improve gait speed and the SPPB in the frail elderly. However, results are inconclusive for endurance outcomes, and no consistent effect was observed on balance and functional mobility.
      Some aspects to be taken into account for future research are the need for larger trials with more rigorous methodology, focusing on a well-defined population of community-dwelling frail elderly. Such trials should test the sustainability over time of the effects of physical activity interventions, particularly task-oriented or functional practice programs, incorporating strategies to increase adherence and assessing performance outcomes in the medium- and long-term. Finally, despite significant work over the past decade, a clear consensus definition of frailty does not emerge from the literature.
      • Rodríguez-Mañas L.
      on behalf of the FOD-CC group
      Searching for an operational definition of frailty: a Delphi method based consensus statement. The Frailty Operative Definition-Consensus Conference Project.
      Important areas for further research include whether disability should be considered a component or an outcome of frailty. A consensus on what is frailty and the criteria to be applied in clinical practice will guide the research and the practice recommendations to clearly defined, homogeneous populations.

      Supplier

      • a.
        CG Information, 740 Granbury Way, Alpharetta, GA 30022.

      Acknowledgments

      We thank Àlex Domingo (Institute on Aging, Barcelona) for developing and conducting the bibliographic search strategy, and Dr. Rydwik, MD, PhD, for providing additional information on her trial. Marta Roqué-Fíguls is a doctorate candidate at the Pediatrics, Obstetrics and Gynecology and Preventive Medicine Department, Universitat Autònoma de Barcelona, Spain.

      Supplemental Appendix S1. Search Strategy

      Cochrane Library search:
      #1 MeSH descriptor Exercise explode all trees
      #2 MeSH descriptor Physical Fitness explode all trees
      #3 MeSH descriptor Muscle Strength explode all trees
      #4 MeSH descriptor Physical Education and Training explode all trees
      #5 MeSH descriptor Exercise Movement Techniques explode all trees
      #6 MeSH descriptor Exercise Therapy explode all trees
      #7 (#1 OR #2 OR #3 OR #4 OR #5 OR #6)
      #10 (exercis* OR fitness* OR yoga OR “tai ji” OR “tai chi” OR taichi OR “resistance training” OR sport* OR gym OR gymnastic* OR pilates OR strength OR balance) in Clinical Trials
      #11 (#7 OR #10)
      #12 (ELDER* OR OLDER* OR OLDEST OR AGED OR AGING* OR AGEING*):ti,ab,kw and (frail* OR fragil*):ti,ab,kw
      #13 (#11 AND #12)
      PubMed, CINAHL, PEDro search:
      #1 frail* OR fragil*
      #2 ELDER* OR OLDER* OR OLDEST OR AGED OR AGING* OR AGEING*
      #3 randomized OR randomised OR controlled OR double-blind OR crt
      ]#6 #1 AND #2 AND #3
      #24 (((((“Sports”[Mesh]OR“Exercise”[Mesh] OR “Physical Exertion”[Mesh]) OR “Exercise Movement Techniques”[Mesh]) OR “Physical Fitness”[Mesh]) OR “Physical Endurance”[Mesh]) OR “Muscle Strength”[Mesh]) OR “Resistance Training”[Mesh] OR “Physical Education and Training”[Mesh] OR “exercise therapy”[Mesh]
      31 exercis* OR fitness* OR yoga OR “tai ji” OR “tai chi” OR taichi OR “resistance training” OR sport* OR gym OR gymnastic* OR pilates OR strength OR balance
      #32 #31 OR #24
      #33 #32 AND #6

      Supplemental Appendix S2. Forest Plot Graphics for Exercise vs Control Comparison

      Figure thumbnail fx1
      Supplemental fig S1Results for gait test. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Figure thumbnail fx2
      Supplemental fig S2Results for endurance. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Figure thumbnail fx3
      Supplemental fig S3Results for ADL. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.
      Figure thumbnail fx4
      Supplemental fig S4Results for adverse effects. Abbreviations: df, degrees of freedom; IV, Inverse Variance method.

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        Archives of Physical Medicine and RehabilitationVol. 99Issue 1
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          There are several errors in the article Giné-Garriga M, Roqué-Fíguls M, Coll-Planas L, Sitjà-Rabert M, Salvà A. Physical exercise interventions for improving performance-based measures of physical function in community-dwelling frail older adults: a systematic review and meta-analysis, published in Archives of Physical Medicine and Rehabilitation 2014; 95: 753-69 ( https://doi.org/10.1016/j.apmr.2013.11.007 ).
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