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Effects of Different Exercise Interventions on Risk of Falls,
Gait Ability, and Balance in Physically Frail Older Adults:
A Systematic Review
Eduardo Lusa Cadore,
1
Leocadio Rodrı´guez-Man˜as,
2
Alan Sinclair,
3
and Mikel Izquierdo
1
Abstract
The aim of this review was to recommend training strategies that improve the functional capacity in physically
frail older adults based on scientific literature, focusing specially in supervised exercise programs that improved
muscle strength, fall risk, balance, and gait ability. Scielo, Science Citation Index, MEDLINE, Scopus, Sport
Discus, and ScienceDirect databases were searched from 1990 to 2012. Studies must have mentioned the effects
of exercise training on at least one of the following four parameters: Incidence of falls, gait, balance, and lower-
body strength. Twenty studies that investigated the effects of multi-component exercise training (10), resistance
training (6), endurance training (1), and balance training (3) were included in the present revision. Ten trials
investigated the effects of exercise on the incidence of falls in elderly with physical frailty. Seven of them have
found a fewer falls incidence after physical training when compared with the control group. Eleven trials
investigated the effects of exercise intervention on the gait ability. Six of them showed enhancements in the gait
ability. Ten trials investigated the effects of exercise intervention on the balance performance and seven of them
demonstrated enhanced balance. Thirteen trials investigated the effects of exercise intervention on the muscle
strength and nine of them showed increases in the muscle strength. The multi-component exercise intervention
composed by strength, endurance and balance training seems to be the best strategy to improve rate of falls, gait
ability, balance, and strength performance in physically frail older adults.
Introduction
Frailty is an age-associated biological syndrome
characterized by decreases in the biological functional
reserve and resistance to stressors due to changes in several
physiological systems, which puts individuals at special risk
for poor outcomes (disability, fall death, and hospitalization)
from minor stressors.
1–4
Frailty encompasses changes that
are associated with aging, life styles, chronic diseases, and
the interactions among them.
5,6
The prevalence of frailty in
people older than 65 years is high (ranging from 7% to
16.3%), increases with age,
7–9
and is the main risk factor for
disability.
10,11
The diagnosis of frailty comprises several do-
mains, including physical impairments (e.g., low gait speed,
fatigue, and low grip strength), weight loss, and low physical
activity.
7
One of the main pathophysiological issues under-
lying the frailty syndrome is the loss of muscle mass that is
induced by biological aging (i.e., sarcopenia). Sarcopenia is
exacerbated by decreased physical activity, causing a decline
in overall function that leads to frailty.
12,13
In addition, other
diseases, such as malnutrition, immobility, anemia, obesity,
cancer, and cardiovascular disease, can accelerate the mor-
bidity and mortality that are induced by the frailty
syndrome.
10
Poor health, disability, and dependency do not have to be
inevitable consequences of aging. Indeed, older adults who
practice healthy lifestyles, avoid sedentariness, participate in
physical exercise (e.g., walking, strength training, or self-
adjusted physical activity), use clinical preventive services,
and continue to engage with family and friends are more
likely to remain healthy, live independently, and incur fewer
health-related costs.
14
The benefits of physical exercise in improving the func-
tional capacity of frail, older adults have been the focus of
considerable recent research.
15–17
Exercise programs tailored
to this population have been demonstrated to be effec-
tive. These interventions, such as resistance training, bal-
ance training, endurance training, coordination training,
1
Department of Health Sciences, Public University of Navarre, Tudela, Navarre, Spain.
2
Division of Geriatric Medicine, University Hospital of Getafe, Madrid, Spain.
3
Institute of Diabetes for Older People (IDOP), University of Bedfordshire, United Kingdom.
REJUVENATION RESEARCH
Volume 16, Number 2, 2013
ªMary Ann Liebert, Inc.
DOI: 10.1089/rej.2012.1397
105
multi-component exercises (i.e., simultaneous strength, en-
durance, and balance training), and Tai Chi, have yielded
beneficial effects on certain functional parameters in frail,
elderly subjects. However, multi-component exercise pro-
grams that include resistance training appear to result in
greater overall enhancements because this type of interven-
tion stimulates several components of physical health, such
as strength, cardiorespiratory fitness, and balance.
16–18
Some studies observed an impaired physical function of
subjects who were not necessarily defined as frail subjects,
but presented severe functional declines such as lower limb
weakness, poor balance, and physical impairments in-
duced by recent history of injurious falls.
9,12,15,17
Thus, there
is a need to define exercise prescription strategies to improve
the functional capacity in elderly who are overall physically
frail.
In addition to reducing the loss of muscle strength and
mass, exercise interventions should focus on reducing the
number of falls and improving balance and gait ability. To
optimize the physical training prescription and meet these
goals in subjects with physical frailty, the most effective type
of exercise program should be identified by considering the
optimal combination of intensity, volume, and frequency of
weekly training that would promote neuromuscular and
cardiovascular adaptations and thus result in improved
functional capacity in the frail elderly. Furthermore, because
muscle power is an important predictor of functional ca-
pacity, strategies to develop skeletal muscle power in this
population must be discussed. Although descriptive and
systematic reviews have been written on the effects of exer-
cise interventions on physical outcomes in frail subjects or
elderly with impaired mobility,
10,19–21
none of these previous
reviews analyzed the effects of different exercise interven-
tions on specific functional outcomes, such as balance, gait
ability, and the risk of falls in elderly with physical frailty.
This review will focus on supervised exercise programs
that improved muscle strength, balance, and gait ability and
decreased the risk of falls. In addition to these effects of
training, the present review will identify other characteristics
of the exercise programs, such as the volume, intensity, and
weekly frequency, as well as possible injuries and side ef-
fects. Training strategies to improve the functional capacity
of elderly individuals with physical frailty will then be re-
commended based on the scientific literature.
Literature Search
Definition of terms
The most frequent frailty definition is focused on the
evaluation of five domains, which are assessed by five cri-
teria (one per each domain): Weight loss, exhaustion, leisure
time activity, gait speed, and grip strength.
1–8
Along with
studies investigating frail and pre-frail subjects, in the pres-
ent review, we searched for studies that classified their
subjects as ‘‘physically frail older adults,’’ basing its classifi-
cation in the physical performance domains of frailty syn-
drome, such as gait speed, grip strength, and exhaustion. In
addition, we also searched for studies on elderly who were
aged 70 years and older and presented severe declines in the
physical function, such as lower limb weakness, poor bal-
ance, slow reaction time, and physical performance impair-
ments induced by recent history of injurious falls.
Search strategy
The Scielo, Science Citation Index, MEDLINE, Scopus,
Sport Discus, and ScienceDirect databases were searched
from February to September, 2012, for published articles
based on original scientific investigations during the period
from 1990 to 2012. The search terms included various com-
binations of the following keywords: ‘resistance training in
frail’, ‘endurance training in frail’, ‘exercise training in el-
derly’, ‘multi-component exercise interventions’, ‘muscle
power in elderly’, ‘muscle strength in elderly’, ‘combined
resistance and aerobic training’, and ‘muscle quality’. The
names of authors who were cited in some of the studies were
also used in the searches. This systematic review is reported
in accordance with the Preferred Reporting Items for Sys-
tematic Reviews and Meta-Analysis (PRISMA) statement.
22
Criteria for study consideration
The search criteria were as follows: (1) The studies must
have been published in English, peer-reviewed, scholarly
journals; (2) dissertations, theses, and conference proceed-
ings were excluded; (3) the studies must have mentioned the
effects of exercise training programs on at least one of the
following four functional parameters in the frail elderly, el-
derly with physical frailty, and elderly with severe functional
declines—incidence of falls, gait, balance, and lower-body
strength; and (4) detailed information about the exercise in-
terventions and the control group must have been provided.
The control group must be a no physical activity group
(maintenance of the habitual lifestyle) or home-based low-
level recreational exercise intervention with only stretching
and relaxation exercises. Exceptions were done in the studies
comparing two different exercise interventions. Data on ex-
ercise interventions that were associated with hormonal
treatments, drug therapy, or other supplements were ex-
cluded. Thus, only the results of the exercise interventions
alone were considered and are described in this review.
Inclusion of studies
From the preliminary search, 79 manuscripts had their
title read and 27 were selected for a second analysis, which
included the reading of the abstracts. Twenty original ran-
domized controlled trials that investigated the effects of ex-
ercise interventions in elderly with physical frailty were
included in the review (Fig. 1); the interventions included
strength training, endurance training, balance training, and
multi-component exercises. Ten of these studies investigated
the effects of multi-component exercise interventions,
15,17,23–29
six studies investigated the effects of resistance training,
30–35
one study investigated the effects of endurance training
combined with yoga,
36
and three studies investigated the ef-
fects of a Tai Chi intervention, which was considered to be a
balance training intervention.
37–39
Assessment of risk of bias
Risk of bias was evaluated according to the PRISMA rec-
ommendation.
22
Study quality assessment included ade-
quate sequence generation, allocation concealment, blinding
of outcomes assessors, use of intention-to-treat analysis, and
description of losses and exclusions. Studies without clear
descriptions of an adequate sequence generation or how the
106 CADORE ET AL.
allocation list was concealed were considered not to have
fulfilled these criteria. Quality assessment was indepen-
dently performed by 2 unblinded reviewers, and disagree-
ments were solved by consensus or by a third reviewer.
Among the included studies, 45% presented adequate se-
quence generation (9 of 20),
15,17,24,28,33,35,36,38,40
60% reported
allocation concealment (12 of 20),
15,17,24,26,32–36,38–40
80% had
blinded assessment of outcomes (16 of 20),
15,17,23–26,31–40
100% described losses to follow-up and exclusions (20 of
20),
15,17,23–40
and 70% used the intention-to-treat principle for
statistical analyses (14 of 20).
15,17,23–26,28,30,33–36,39,40
Subject characteristics
Thesamplesizeofthestudiesthatwereincludedinthe
present review was 171.8 –196.6 subjects (ranging from 9
16
to
684 subjects
38
). The mean –standard deviation (SD) of the
subjects’ ages was 78.2 –5.3 (ranging from 70 –2
16
to 90 –2
35
).
In seven of the 20 included studies, the subjects were defined as
frail, pre-frail, and mild-to-moderate frail.
27–29,31–33,36
From
these studies, six presented criteria for classification of frailty
consistent with the literature.
27,29,31–33,36
Five studies classified
their subjects as elderly with physical frailty using criteria
consistent with the literature.
23–26,30
Six studies investigated
elderly aged 70 and older presenting recent history of injurious
falls, transition for frailty, and recent illness-induced functional
decline.
17,34,37–40
Finally, one study investigated sarcopenic
women presenting poor strength and gait ability levels based
on literature criteria,
15
and one study investigated elderly aged
90 and older.
35
Physical outcomes measurements
Among the included studies, the gait ability was assessed
by the 6-meter walk test and the Timed Up and Go test. The
balance performance was assessed by the tandem and semi-
tandem tests, Berg balance scale, one leg stand test, and
clinical test of sensory interaction and balance. The strength
measurements were done using the one repetition maximum
test (1RM) and isokinetic and isometric dynamometry. Data
on incidence of falls were assessed using validated ques-
tionnaires.
Effects of Exercise Programs on Different Physical
Outcomes in Elderly with Physical Frailty
Incidence of falls
Ten studies investigated the effects of exercise interven-
tions on the incidence of falls in elderly with physical frailty.
Seven of the studies found a lower incidence of falls after the
physical training period
23,26,28,35,37,38,40
compared with the
control group, and three studies did not demonstrate any
difference.
17,33,39
Four of the studies that showed a reduced
incidence of falls used multi-component exercise programs in
their intervention,
23,26,28,40
one study used only resistance
exercises,
35
and two studies used Tai Chi exercises.
37,38
The
mean decrease in the incidence of falls ranged from 22% to
58%. Among the three trials that did not reveal a significant
effect, in the study of Latham et al.,
33
the subjects partici-
pated in a home-based resistance exercise program using
60–80% of the individuals’ 1RM with ankle cuffs, with no
balance exercises included in the exercise intervention. In the
study of Freiberger et al.,
17
the subjects participated in a
multi-component exercise intervention; the authors justified
their results based on the study’s limitations, such as the
statistical power calculation, which was based on the Timed
Up and Go test data and may have prevented the results
from reaching statistical significance. In the study by Wolf
et al.,
39
the incidence of falls was compared between the Tai
Chi and wellness education interventions. In this study, the
incidence of falls was reduced in both groups after 48 weeks;
however, the authors stated that their study had the power
to detect a 50% reduction in the rate of falls, which did not
occur in their study.
Gait ability
Eleven trials investigated the effects of exercise interven-
tions on the gait ability in elderly with physical frailty. Six
studies revealed enhancements in the subjects’ gaits after the
physical training period,
15,17,23,30,32,36
whereas five studies
demonstrated no improvement.
26,33–35,38
Three of the studies
that demonstrated improvements in their subjects’ gaits used
multi-component exercise programs,
15,17,23
two studies used
only resistance exercises,
32,35
and one study used endurance
training combined with yoga.
36
The mean improvement in
gait ranged from 4% to 50%. Among the six studies that did
not reveal a significant effect, the study of Barnett et al.,
26
used a 1-year, home-based exercise intervention; the authors
justified the absence of changes in gait based on the em-
phasis on balance-related exercises and a low-frequency ex-
ercise program. Specific exercises for improving gait were
not used in the studies of Latham et al.,
33
Sullivan et al.,
34
Serra-Rexach et al.,
35
(resistance training intervention), Ha-
gedorn and Holm,
29
(resistance training and balance inter-
ventions), and Taylor et al.
38
(Tai Chi intervention).
Balance
Ten studies investigated the effects of exercise interven-
tions on balance in elderly with physical frailty. Eight of the
investigations revealed enhanced balance after the physical
training period,
17,23–26,29,39,40
whereas two studies did not
demonstrate any improvement.
28,33
Seven of the studies that
revealed enhancements in balance used multi-component
exercise programs that included balance training,
17,23–26,29,40
and one study included Tai Chi exercises.
39
The mean im-
provement in balance ranged from 5% to 80%. Of the two
research groups that did not determine a significant effect,
Lord et al.
28
suggested that their exercise interventions were
of insufficient intensity to produce gains in this domain; in-
deed, they mentioned in the intervention description that
most of the utilized exercises emphasized social interaction
and enjoyment.
28
As previously mentioned, the study of
Latham et al.
33
did not include any balance exercises in the
intervention.
Muscle strength
Thirteen studies investigated the effects of exercise inter-
ventions on lower-body muscle strength in elderly with
physical frailty. Nine studies revealed increased muscle
strength after the physical training period,
23,24,29–32,34,35,40
whereas four studies did not identify any improve-
ment.
15,26,28,33
Five of the studies that demonstrated en-
hanced strength used resistance exercise programs,
30–32,34,35
EFFECTS OF EXERCISE IN PHYSICALLY FRAIL OLDER ADULTS 107
and four studies used multi-component exercise interven-
tions.
23,24,29,40
The mean increase in strength ranged from 6%
to 60%. Of the four studies that did not reveal a significant
effect on muscle strength, Latham et al.
33
and Barnett et al.
26
used home-based exercise interventions, which may not have
provided sufficient stimuli for facilitating strength gains. In
the exercise intervention of Lord et al.,
28
it appears that only
weight-bearing exercises were performed, and no details
were provided regarding the exercise intensity used. In the
study of Kim et al.,
15
the subjects performed gait and balance
and strength exercise with ankle-weight cuffs from 0.50 kg to
1.50 kg and resistance bands, which may not have provided
sufficient stimuli for facilitating strength gains.
What Is the Best Exercise Intervention to Reduce
Falls and Disability and Improve Balance in Elderly
with Physical Frailty?
Several studies have investigated the effects of various
physical exercise programs on the functional capacity of el-
derly with physical frailty.
16,24,26,30,32
Resistance training,
endurance training, balance training, and combinations of
these programs (i.e., multi-component exercises) have yiel-
ded beneficial effects on certain functional parameters in frail
elderly subjects. As expected, greater gains in strength have
been achieved when resistance training was used in exercise
programs.
24,26,30
In addition, exercise programs (including
resistance training) have also enhanced functional parame-
ters, such as gait and balance, and reduced the risk of
falls.
17,23,41
Table 1 summarizes the methods applied and the
results obtained in the studies that have investigated exercise
interventions in elderly subjects with physical frailty.
Resistance training
Studies on resistance training in the elderly have shown
that this type of exercise intervention can improve neuro-
muscular activity, muscle mass, strength, power, and func-
tional capacity, as well as enhance cardiovascular function
when prescribed in combination with aerobic training.
42–47
Notwithstanding, a limited number of studies have investi-
gated the effects of resistance training in the oldest-old and
frail subjects. Fiatarone et al.
30
studied the adaptations in-
duced by resistance training in 100 frail elderly men and
women. The subjects underwent resistance training that
consisted of 3 sets of 8 repetitions at 80% of 1RM, 3 times per
week for 10 weeks. The results revealed that the resistance
training groups improved their habitual gait velocities, stair-
climbing abilities, and overall levels of physical activity.
Moreover, resistance training significantly enhanced the leg
muscle strength outcomes ( p<0.001). In a study by Serra-
Rexach et al.,
35
20 oldest-old subjects (90–97 years of age)
underwent resistance training 3 times a week for 8 weeks,
with 2–3 sets of 8–10 repetitions at 30% of 1RM in the initial
phase of training, progressing to 70% of 1RM. The results
demonstrated increases in the leg press strength (10.6 kg;
p<0.05), but no changes were observed in the speed during
an 8-meter walking test, the time to complete a 4-step stair
test, and the results of the Timed Up and Go test. Using a
similar progression of intensity, Hennessey et al.,
31
observed
significant 1RM increases after 24 weeks of training in frail
elderly individuals (71.3 –4.5 years of age). In this study, the
participants performed 3 sets of 8 repetitions at 20% of 1RM,
progressing gradually to 95% of 1RM. In another study,
Lustosa et al.
32
observed significant improvements in the
Timed Up and Go test, gait speed, and power at 180.s
-1
in
pre-frail elderly subjects (72 –4 years of age) after 12 weeks
of resistance training that was performed 3 times per week.
In this study, a half-squat exercise was performed using the
participants’ body weights as resistance.
In a study of the effectiveness of different training inten-
sities (% of 1RM) in frail elderly subjects (79.4 –7.4 years of
age), Sullivan et al.
34
have shown greater strength increases
in the training groups that underwent progressively the in-
tensity of the resistance training (starting at 20% and pro-
gressing to 80% of 1RM) compared with the low-intensity
training groups that underwent resistance training (at 20% of
1RM during the entire 12-week training period).
In a study investigating the efficacy of home-based resis-
tance training, Latham et al.
33
assessed frail elderly men and
women who were over 65 (79.1 –6.9) years of age. The
subjects performed 10 weeks of home-based resistance
training, with intensities between 60% and 80% of 1RM (3
sets of 8 repetitions). After the training period, no effects of
the resistance training were detected regarding the incidence
of falls, the timed walking test, the Timed Up and Go test,
and the Berg balance test compared with the control group.
In addition, no difference was observed in quadriceps
strength between the resistance training group and the con-
trol group after the training period.
In summary, resistance training programs that are per-
formed 3 times a week, with 3 sets of 8 to 12 repetitions and
an intensity starting at 20%–30% and progressing to 80% of
1RM, may be well tolerated by frail subjects, resulting in
positive effects on gait and gains in muscle strength. Table 2
summarizes the resistance training methods and the results
obtained in the studies that investigated the adaptations in-
duced by resistance training in frail elderly individuals. No
injuries or side effects were mentioned in the studies that
investigated the effects of strength training in frail elderly
subjects.
30–35
To optimize functional capacity, resistance
training programs should include exercises in which the
participants’ body weights are used for resistance and in
which usual daily activities are simulated (such as the ‘‘sit to
stand’’ exercise). Furthermore, resistance exercises that are
performed with a high speed of motion promote greater
improvements in the functional task performance of healthy
elderly individuals.
48,49
Thus, the same benefits of high-
speed strength training may be observed in frail elderly pa-
tients, and this possibility should be investigated in future
studies.
Endurance training
Aging is associated with a decline in the cardiorespiratory
capacity that is primarily associated with a decrease in the
maximal heart output caused by a reduced maximum stroke
volume and heart rate and changes in the oxygen arterio-
venous difference.
50
To counteract these phenomena, en-
durance training induces central and peripheral adaptations
that enhance the maximal oxygen uptake (VO
2max
) and the
ability of skeletal muscle to generate energy via oxidative
metabolism.
27,51–53
However, elderly subjects with severe
functional declines may not be able to perform endurance
training to recover some of their neuromuscular capacity.
108 CADORE ET AL.
Indeed, it has been demonstrated that power and strength
levels are positively associated with the cardiorespiratory
capacity in elderly subjects.
54,55
Thus, endurance interven-
tions in frail elderly individuals have previously included
endurance training within multi-component exercise pro-
grams.
15–17,28,29
Endurance exercises for the elderly include walking with
changes in pace and direction,
15,17,26
treadmill walking,
16,29
step-ups, stair climbing, and stationary cycling.
16
The en-
durance exercises may start with a duration of 5–10 min in
the first weeks of training, progressing to 15–30 min for the
remainder of the program.
17,28,29
Ehsani et al.
27
investigated
the effect of endurance exercise sessions in frail octogenari-
ans, starting with 20 min and progressing to 60 min of
walking at an intensity of 70%–75% of the maximal heart
rate. However, in this study, the endurance training was
performed after two previous phases of training, namely
1 month of physical therapy and 1 month of strength
Table 1. Effects of Different Types of Exercise Intervention on Rate of Falls, Gait Ability,
Balance, Cardiorespiratory, and Strength Performance
Authors N, age Intervention Primary results
Fiatarone et al.
30
100, 87 RT vs. RT +SUP: 3x/wk, 10 wk [Strength outcomes (26%–215%);
[gait speed (9%–15%).
Wolf et al.
37
200, 70 BT composed by Tai-Chi exercises,
2/wk, 15 wk.
YRate of falls (47%).
Lord et al.
28
551, 79 MCEP:RT +ET +BT, 2/wk, 48 wk YRate of falls (22%).
Hauer et al.
23
57, 82 MCEP:RT +BT, 3/wk, 12 wk [Strength (75%);
Yrate of falls (25%).
Kenny et al.
36
99, 76 Yoga +chair aerobics with and with no
DHEA SUP, 2/wk, 24 wk
[TUG test (4%);
[strength only in the SUP group.
Binder et al.
24
115, 83 MCEP: ET +RT +BT +COOT, 3/wk, 36 wk. [Strength outcomes;
[balance;
[VO
2ma
´x
;
[physical performance score.
King et al.
25
155, 77 MCEP: ET +RT +BT +FT, 1-3/wk, 48 wk. [Balance (35%).
Latham et al.
33
243, 79 Home-based RT, 3/wk, 10 wk. No changes in strength, falls, balance
and gait speed.
Barnett et al.
26
163, 75 MCEP: BAL +TAI +ET +BWRT, 1 yr, 37
supervised sessions.
No changes in strength, reaction time
and walking speed.
[Balance (6%–15%);
YRate falls: EG vs. CG (36%).
Ehsani et al.
27
46, 82 MCEP: ET +RT, 3/wk, 24 wk. [VO
2ma
´x
;
Wolf et al.
39
286, 81 BT composed by Tai-Chi exercises, 2/wk,
48 wk vs. active control with low level
RT +ET, with no BT.
No difference between groups in the
incidence of falls.
Sullivan et al.
34
29, 79 RT: high vs. low intensity, with or with no
megestrol acetate SUP, 12 wk.
[Strength (23%) only in the RT at high
intensity.
Hagedorn and
Holm
29
27, 81 MCEP: RT +BT with and with no visual
computer feedback 2/wk, 12 wk,
[Strength (19%);
[Overall balance scores (80%);
[6-min walk test (8%).
Lustosa et al.
32
48, 72 BWRT: 3x/wk, 10 wk, [Gait speed (10%);
[strength outcomes (6%).
Serra-Rexach
et al.
35
40, 92 RT, 3/wk, 10 wk. [Strength (10.6kg);Yfalls (1.2 fewer).
Freiberger et al.
17
197, 76 3 MCEP: ST +BT vs. ET +ST +BT vs.
ST +BT +falls risk education. 2/wk, 16 wk.
[Gait speed in ST +BT and
ET +ST +BT.
No changes in the number of falls.
Kim et al.
15
115, 79 MCEP vs. MCEP +SUP: 2x/wk, 12 wk.
MCEP =BT +ET +BWRT.
[Strength (6%);
[gait speed (12%–17%).
Clemson et al,
40
317, 83 MCEP:RT +BT, 3/wk, 12 wk YRate of falls (31%);
[balance
Henessey et al.
31
31, 71 RT vs. RT +GH SUP: 3/wk, 10 wk [Strength (*50%).
Taylor et al.
38
684, 74 BT composed by TAI, 1/ wk vs. 2/wk, 20 wk. YRate of falls (58%).
RT, Resistance training; ET, endurance training, BT, balance training; BWRT, body weight resistance training; MCEP, multicomponent
exercise program; TAI, Tai-Chi exercises; FT, flexibility training; COOT, coordenation training; SUP, supplementation; GH, growth hormone;
DHEA, dehydroepiandrosterone; wk, weeks; [, increase; Y, reduction.
EFFECTS OF EXERCISE IN PHYSICALLY FRAIL OLDER ADULTS 109
training. This exercise intervention resulted in a 12.5% in-
crease in the VO
2max
.
27
Thus, it may be necessary to
strengthen the neuromuscular system before initiating en-
durance training to achieve these cardiovascular adaptations.
Other methods for controlling the exercise intensity may be
the use of the rate-of-perceived-exertion scale
15
(i.e., Borg
scale),
56
in which intensities of 12–14 appear to be well tol-
erated.
Aerobic capacity is an important component of physical
fitness, and endurance training should be part of the exercise
Table 2. Training Characteristics of Systematic Resistance Training Programs Applied in Frail Elderly
Authors
Weekly
frequency
(times per week)
Volume
(sets x
repetitions) Intensity (% of 1RM) Adverse effects
Fiatarone et al.
30
33·8 80% of 1RM No adverse effects mentioned.
Hauer et al.
23
33·10 70%–90% of 1RM No adverse effects mentioned.
Binder et al.
24
3 1: 1–2 ·6–8
2: 3 ·8-12
1: 65% of 1RM
2: 85%–100%
of initial 1RM
1 subject dropped out for medical
reasons related to study.
Sullivan et al.
34
23·8 10%–20% vs. 20%–80%
of 1RM
No adverse effects mentioned.
Hagedorn
and Holm
29
23·10–15RM Not mentioned,
repetitions until failure
No adverse effects mentioned.
Villareal et al.
16
3 1–3 ·8–12 65%–80% of 1RM 1 subject related shoulder pain.
Serra-Rexach et al.
35
3 2–3 sets of 8–10
repetitions
30% progressing to
70% of 1RM
No adverse effects mentioned.
Henessey et al.
31
33·8 20% progressing to
90% of 1RM
No adverse effects mentioned.
Izquierdo et al.
18
2 1–3 ·8–10 40% progressing to
60% of 1RM
No adverse effects mentioned.
1RM, maximum repetitions.
FIG. 1. Search process.
110 CADORE ET AL.
routine for frail elderly individuals. Although no studies
have compared the effectiveness of various endurance
training programs (i.e., different intensities and volumes),
this type of exercise should follow the basic principles of
training, with the intensity and duration progressively in-
creased based on the capacity of each participant.
Balance training
Balance training is another type of exercise intervention that
is aimed at preventing falls.
16,29
It is difficult to assess the effect
of balance training alone on the risk of falls and on balance
outcomes because this type of intervention is conventionally
included in multi-component exercise programs.
16,26,28
Balance training generally includes exercises, such as
tandem foot standing, multi-directional weight lifts, heel–toe
walking, line walking, stepping practice, standing on one leg,
catching/throwing a ball, altering the base of support,
weight transfers (from one leg to the other), and modified Tai
Chi exercises.
15,26,28
Studies have demonstrated that Tai Chi is
an effective fall-prevention intervention.
37,38,57
In an investiga-
tion of the effects of intense Tai Chi interventions, Wolf et al.
37
determined that 15 weeks of Tai Chi reduced the occurrence of
falls in elderly subjects. Likewise, in a recent study by Taylor
et al.
38
both Tai Chi and home-based multi-component exercise
programs were found to reduce the risk of falls (58%) in
community-residing older adults (74.5 –6.5 years).
For the above-mentioned balance exercises, the training
should progress from easy to more difficult exercises, with
the physiological intensity of training increasing over time.
23
However, the effects of balance training on the risk of falls
should be carefully analyzed because the effectiveness of this
intervention has been demonstrated only when it is com-
bined with other components of physical fitness, such as
strength and endurance training.
Multi-component exercise programs
Multi-component exercise programs appear to be the most
effective interventions for improving the overall health status
of frail elderly individuals.
15,16,26,28
This statement is sup-
ported by the literature, in which positive effects on func-
tional capacity are more often observed when more than one
physical-conditioning component (i.e., strength, endurance,
or balance) comprises the exercise intervention,
15,16,26,28
compared with only one type of exercise.
35,38
Along with the
evidence provided, it is reasonable to suggest that different
kinds of stimulus, such as to improve muscle strength and
mass, cardiovascular function, gait ability, and balance, and
promote a greater increase in independence and in the ability
to perform daily activities. It is well known that the resis-
tance exercise programs are recommended to improve neu-
romuscular function,
44,45,47
endurance exercise programs are
recommended to enhance cardiovascular function,
46
and
balance training stimulates improvements on balance per-
formance.
29
Thus, multi-component exercise programs could
be composed with more emphasis in one these three types of
exercise interventions, according to a specific goal (i.e.,
strength and muscle mass in sarcopenic elderly).
Lord et al.
28
found that 12 weeks of an intervention that
included aerobics, slow-to-moderate-paced walking, and
flexibility, balance and weight-bearing exercises resulted in
22% fewer falls in frail elderly individuals compared with
control subjects. In addition, there were small increases in the
reaction time over a 6-min walking distance. Similar results
were observed by Barnett et al.,
26
who demonstrated that 1
year of a home-based multi-component exercise program
(composed of functional, strength, balance, and aerobic ex-
ercises) resulted in 40% fewer falls in an exercise intervention
group of elderly with physical frailty compared with a con-
trol group. Recently, Clemson et al.
40
investigated the effects of
12 months of an exercise intervention that consisted of balance
and strength exercises performed with ankle cuff weights by
elderly participants with recent history of injurious falls. These
authors demonstrated a reduction in the rate of falls (31%) and
greater strength and balance performance in the exercise
groups after the intervention period. In another study, Iz-
quierdo et al.
18
observed that 12 weeks of progressive resis-
tance training (8–10 repetitions at 40%–60% of 1RM) by using
resistance-variable machines (Exercycle, S.L. [BH Group],
Vitoria, Spain) combined with balance exercises yielded posi-
tive effects on the incidence and risk of falls and on the muscle
strength, dual-task performance, gait, and balance in very el-
derly institutionalized and frail patients.
The above-mentioned results are important because they
suggest that multi-component exercise interventions may re-
duce the incidence of falls and consequently prevent disability,
morbidity, and death. Other studies have demonstrated the
benefits of performing various types of exercises on the health
and physical independence of frail elderly individuals.
15,16,29
The physical outcomes that were improved in these studies
include balance,
29
gait,
15
muscle strength,
16,24
and VO
2peak
.
24
Some investigations have compared the effects of different
multi-component exercise interventions. Binder et al.
24
ob-
served greater enhancements in strength, VO
2peak
, and other
physical function tests (i.e., the Physical Performance Test and
Functional Status Questionnaire scores) in individuals who
participated in an assisted exercise intervention program
(strength, endurance, and balance) compared with those who
participated in a home-based exercise program. In another
study, Hagedorn and Holm
29
compared a combination of
strength training with two different types of balance training—
traditional training, which included standing on different
surfaces with opened or closed eyes (TB), and balance training
using a computer feedback system, which registered the po-
sition of the body (CB). The results of this study revealed that
both groups of frail elderly individuals increased their muscle
strength and physical endurance, with the CB group exhibiting
a remarkable increase during the games that were used for
training. A recent investigation by Freiberger et al.
17
compared
the effects of three different multi-component exercise pro-
grams on several physical outcomes in elderly with history of
falls. The results revealed that the groups who performed
balance exercises combined with strength training (with or
without endurance training) exhibited greater improvements
in walking speed and in the Timed Up and Go and Romberg
tests than did a group that had received fall-risk education to
address fall-related psychological aspects. However, the three
intervention groups had better physical outcome scores than
the control group after the intervention period.
17
The above-mentioned results demonstrate the effectiveness
of multi-component exercise programs in improving the
physical fitness and health of frail elderly individuals. It should
be noted, however, that the progression of training and the
inclusion of different exercise stimuli should follow the
EFFECTS OF EXERCISE IN PHYSICALLY FRAIL OLDER ADULTS 111
principles of physical fitness and should be slow and gradual,
especially in frail participants. An interesting approach to in-
creasing the training intensity was presented by Binder et al.
24
These authors used a training model with three blocks of 3
months, starting with exercises focused on flexibility, balance,
reaction speed, and coordination in the first phase; switching
to progressive resistance training in the second phase; and
advancing to endurance training on treadmills, stationary bi-
cycles, or rowing machines in the third phase.
24
Summary
A multi-component exercise intervention program that
consists of strength, endurance, and balance training appears
to be the best strategy for improving gait, balance, and
strength, as well as reducing the rate of falls in elderly indi-
viduals and consequently maintaining their functional ca-
pacity during aging. Most of the studies demonstrating
improvements in gait, balance, and fall risk have used multi-
component exercise training as intervention in their subjects.
However, the studies in which systematic resistance training
was performed (either alone or as part of multi-component
exercise programs) revealed greater strength gains in the el-
derly with physical frailty or severe functional declines. The
absence of changes in the functional and strength outcomes
that were measured in some of the investigations indicates
that the exercise prescription must be carefully adapted to
provide a sufficient stimulus for improving the functional
capacity of frail subjects. In addition, the present review fo-
cused only on the physical function domains of the concepts
of frailty and physical frailty. Thus, this systematic review is
only able to recommend strategies to improve the physical
function of physically frail individuals. On the basis of recent
evidence, exercise strategies to improve neuromuscular and
cardiovascular parameters and functional performance in
frail elderly individuals should include the following:
Resistance-training programs should be performed two
to three times per week, with three sets of 8–12 repeti-
tions at an intensity that starts at 20%–30% and pro-
gresses to 80% of 1RM.
To optimize the functional capacity of individuals, re-
sistance training programs should include exercises in
which daily activities are simulated, such as the sit-to-
stand exercise.
Endurance training should include walking with chan-
ges in pace and direction, treadmill walking, step-ups,
stair climbing, and stationary cycling. Endurance exer-
cise may start at 5–10 min during the first weeks of
training and progress to 15–30 min for the remainder of
the program. The Rate of Perceived Exertion scale is an
alternative method for prescribing the exercise intensity,
and an intensity of 12–14 on the Borg scale
56
appears to
be well tolerated.
Balance training should include several exercise stimuli,
such as tandem foot standing, multi-directional weight
lifts, heel–toe walking, line walking, stepping practice,
standing on one leg, weight transfers (from one leg to
the other), and modified Tai Chi exercises.
Multi-component training programs should include
gradual increases in the volume, intensity, and complexity
of the exercises, along with the simultaneous performance
of resistance, endurance, and balance exercises.
These recommendations, which are based on this sys-
tematic and narrative review, should be tested in new
clinical trials that are specifically designed for such a
purpose or in a formal meta-analysis.
Acknowledgments
This work was supported in part by the Spanish Depart-
ment of Health and Institute Carlos III of the Government of
Spain [Spanish Net on Aging and frailty; (RETICEF)], De-
partment of Health of the Government of Navarre and
Economy and Competitivity Department of the Government
of Spain, under grants numbered RD12/043/0002, 87/2010,
and DEP2011-24105 respectively. This project is also funded
in part by the European Commision (FP7-Health, Project
reference 278803).
Author Disclosure Statement
No competing financial interests exist.
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Address correspondence to:
Mikel Izquierdo
Department of Health Sciences
Public University of Navarra
Campus of Tudela
Av. de Tarazona s/n.
31500 Tudela (Navarra)
Spain
E-mail: mikel.izquierdo@gmail.com
Received: December 10, 2012
Accepted: January 17, 2013
114 CADORE ET AL.
