Progressive resistance strength training for improving physical
function in older adults
Chiung-ju Liu
1
and Nancy K Latham
2
1
Department of Occupational Therapy, Indiana University at Indianapolis, Indianpolis, Indiana,
USA
2
Health and Disabilty Research Institute, School of Public Health, Boston University, Boston, MA,
USA
Abstract
Background—Muscle weakness in old age is associated with physical function decline.
Progressive resistance strength training (PRT) exercises are designed to increase strength.
Objectives—To assess the effects of PRT on older people and identify adverse events.
Search methods—We searched the Cochrane Bone, Joint and Muscle Trauma Group
Specialized Register (to March 2007), the Cochrane Central Register of Controlled Trials (The
Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 01, 2008), EMBASE (1980 to
February 06 2007), CINAHL (1982 to July 01 2007) and two other electronic databases. We also
searched reference lists of articles, reviewed conference abstracts and contacted authors.
Copyright © 2009 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Contact address: Chiung-ju Liu, Department of Occupational Therapy, Indiana University at Indianapolis, 1140 W Michigan ST CF
303, Indianpolis, Indiana, 46202, USA. liu41@iupui.edu.
*
Indicates the major publication for the study
Contributions of Authors: For the first version of the review (completed 2002), Dr Nancy Latham, Dr Craig Anderson, Dr Derrick
Bennett and Dr Caroline Stretton contributed to the development of the protocol, the analysis and interpretation of the data and the
write-up of the review. Dr Nancy Latham took the lead in conducting the analyses and writing the protocol and review. In addition, Dr
Latham and Dr Stretton conducted the searches, identified the trials, conducted the quality assessments and extracted the data. Dr
Bennett provided methodological and statistical guidance for the review. Dr Anderson served as the adjudicator when a consensus
about data issues could not be reached between the two reviewers, and provided guidance about the methods and interpretation of the
review.
The review was substantially updated in 2009 by Dr Chiung-ju Liu and Dr Nancy Latham. Dr Liu took the lead in conducting the
update, which included undertaking the searches, screening search results, organizing retrieval of papers, screening retrieved papers
against inclusion criteria, appraising quality of papers, extracting data, contacting authors for additional information, entering data into
RevMan, doing the analyses and writing up. The project was completed when Dr Liu was a post-doctoral research fellow at the Health
and Disability Research Institute at Boston University. Dr Latham assisted in identifying the trials, conducting the quality assessments,
extracting the data, interpreting the results and writing the review.
Both Dr Chiung-ju Liu and Dr Nancy Latham are guarantors for the review.
Declarations of Interest: Dr. Latham is an author for two trials. The trials were rated independently by other reviewers in the first
review.
Notes: Substantial updates of reviews such as this one often take a considerable time to prepare and then take through the editorial
process. They can therefore seem ‘out of date’ before publication, particularly in research active areas. However, although an updated
search made in May 2008 revealed nine more potentially eligible trials (which await assessment, pending the next update), it is
unlikely that the review's main findings will be substantively changed by these. [Comment by Helen Handoll, Co-ordinating Editor,
May 2009]
NIH Public Access
Author Manuscript
Cochrane Database Syst Rev. Author manuscript; available in PMC 2015 February 11.
Published in final edited form as:
Cochrane Database Syst Rev. ; (3): CD002759. doi:10.1002/14651858.CD002759.pub2.
NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript
Selection criteria—Randomised controlled trials reporting physical outcomes of PRT for older
people were included.
Data collection and analysis—Two review authors independently selected trials, assessed
trial quality and extracted data. Data were pooled where appropriate.
Main results—One hundred and twenty one trials with 6700 participants were included. In most
trials, PRT was performed two to three times per week and at a high intensity. PRT resulted in a
small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95%
CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a
modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to
0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD
-0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059
participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction
in pain following PRT (6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was
no evidence from 10 other trials (587 participants) that PRT had an effect on bodily pain. Adverse
events were poorly recorded but adverse events related to musculoskeletal complaints, such as
joint pain and muscle soreness, were reported in many of the studies that prospectively defined
and monitored these events. Serious adverse events were rare, and no serious events were reported
to be directly related to the exercise programme.
Authors' conclusions—This review provides evidence that PRT is an effective intervention
for improving physical functioning in older people, including improving strength and the
performance of some simple and complex activities. However, some caution is needed with
transferring these exercises for use with clinical populations because adverse events are not
adequately reported.
Medical Subject Headings (MeSH)
Activities of Daily Living; Muscle Weakness [*rehabilitation]; Randomized Controlled Trials as
Topic; Recovery of Function [physiology]; Resistance Training [adverse effects; *methods]
MeSH check words
Aged; Humans
Background
Description of the condition
Muscle strength is the amount of force produced by a muscle. The loss of muscle strength in
old age is a prevalent condition. Muscle strength declines with age such that, on average, the
strength of people in their 80s is about 40% less than that of people in their 20s (Doherty
1993). Muscle weakness, particularly of the lower limbs, is associated with reduced walking
speed (Buchner 1996), increased risk of disability (Guralnik 1995) and falls in older people
(Tinetti 1986).
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Description of the intervention
Progressive resistance training (PRT) is often used to increase muscle strength. During the
exercise, participants exercise their muscles against some type of resistance that is
progressively increased as strength improves. Common equipment used for PRT includes
exercise machines, free weights, and elastic bands.
How the intervention might work
Contrary to long held beliefs, the muscles of older people (i.e. people aged 60 years and
older) continue to be adaptable, even into the extremes of old age (Frontera 1988). Trials
have revealed that older people can experience large improvements in their muscle strength,
particularly if their muscles are significantly overloaded during training (Brown 1990;
Charette 1991; Fiatarone 1994).
Why it is important to do this review
Despite evidence of benefit from PRT in terms of improving muscle strength, there is still
uncertainty about how these effects translate into changes in substantive outcomes such a
reduction in physical disability (Chandler 1998). Most studies have been under-powered to
determine the effects of PRT on these outcomes or have included PRT as part of a complex
intervention. In addition, there is uncertainty about the effects of PRT when more pragmatic,
home or hospital-based programmes are used, and the safety and effectiveness of this
intervention in older adults who have health problems and/or functional limitations. Finally,
there is uncertainty about the relative benefits of PRT compared with other exercise
programmes, or the effectiveness of varying doses of PRT (i.e. programmes of varying
intensity and duration). This update of our review (Latham 2003a) has continued to assess
and summarise the evidence for PRT.
Objectives
To determine the effects of progressive resistance strength training (PRT) on physical
function in older adults through comparing PRT with no exercise, or another type of care or
exercise (e.g. aerobic training). Comparisons of different types (e.g. intensities, frequencies,
or speed) of PRT were included also. We considered these effects primarily in terms of
measures of physical (dis)ability and adverse effects, and secondary measures of functional
impairment (muscle strength & aerobic capacity) and limitation (e.g. gait speed).
Methods
Criteria for considering studies for this review
Types of studies—Any randomised clinical trials meeting the specifications below were
included. All non-randomised controlled trials (e.g. controlled before and after studies) were
excluded. Also excluded were trials for which details were provided that indicated these
used quasi-randomised methods, such as allocation based on date of birth.
Types of participants—Older people, resident in institutions or at home in the
community. Trials were included if the mean age of participants was 60 or over, but
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excluded if participants aged less than 50 were enrolled. The participants could include frail
or disabled older people, people with identified diseases or health problems, or fit and
healthy people.
Types of interventions—Any trial that had one group of participants who received PRT
as a primary intervention was considered for inclusion. PRT was defined as a strength
training programme in which the participants exercised their muscles against an external
force that was set at specific intensity for each participant, and this resistance was adjusted
throughout the training programme. The type of resistance used included elastic bands or
tubing (i.e. therabands), cuff weights, free weights, isokinetic machines or other weight
machines. This type of training could take place in individual or group exercise
programmes, and in a home-based or gymnasium/clinic setting. Studies that utilised only
isometric exercises were excluded. Studies that included balance, aerobic or other training as
part of the exercise intervention (and not simply part of the warm-up or cool-down) were
also excluded.
We found the following comparisons between groups in the trials:
•
PRT versus no exercise (greatest difference between groups was expected)
•
Different types of PRT: high intensity versus low intensity, high frequency versus
low frequency, or higher speed (power training) versus regular speed (greatest
effect expected in the higher intensity groups). Power training refers to the type of
PRT that emphasizes speed.
•
PRT versus regular care (including regular therapy or exercise)
•
PRT versus another type of exercise (smaller difference between groups expected)
Types of outcome measures
Primary outcomes: This review assessed physical function in older adults at the level of
impairment, functional limitation and disability. The primary outcome of this review was
physical disability. This was assessed as a continuous variable. The outcomes were
categorized based on the Nagi model of health states (Nagi 1991). In this model, disability is
considered to be a limitation in performance of socially defined roles and tasks that can
relate to self-care, work, family etc. In this review, the primary assessment of physical
disability included the evaluation of self-reported measures of activities of daily living
(ADL, i.e. the Barthel Index) and the physical domains of health-related quality of life
(HRQOL, i.e. the physical function domain of the SF-36). Data from these measures were
pooled for the main analysis of physical disability. However, because these two types of
measures (ADL and physical domains of HRQOL) evaluate different health concepts, they
were also evaluated in separate analyses. The Nagi model also includes firstly, the domain
of ‘functional limitations’ which are limitations in performance at the level of the whole
person and includes activities such as walking, climbing or reaching, and secondly,
‘impairments’ that are defined as anatomical or physiological abnormalities.
Since the protocol of this review was written, the International Classification of Functioning,
Disability and Handicap (ICF) has been released (WHO 2001). Under this system, disability
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is an umbrella term for impairments, activity limitations and participation restrictions. Using
the ICF, the outcome measures evaluated in this review fall under the domains of
impairments, limitations in simple activities (similar to ‘functional limitations’ in Nagi's
system) and limitations in complex activities (similar to some aspects of disability in Nagi's
model).
Secondary outcomes
Measures of impairment (outcome comparisons 2 and 3): The following secondary
outcomes were assessed as continuous variables:
•
muscle strength (e.g. 1 repetition maximum test, isokinetic and isometric
dynamometry)
•
aerobic capacity (e.g. 6 minute walk test, VO2 max: maximal oxygen uptake during
exercise)
Measures of functional limitation (simple physical activities): The following secondary
outcomes were assessed as continuous variables:
•
balance (e.g. Berg Balance Scale, Functional Reach Test)
•
gait speed, timed walk
•
timed ‘up-and-go’ test
•
chair rise (sit to stand)
•
stair climbing (added in 2008)
The balance outcome is also reviewed in a separate Cochrane review (Howe 2007).
Other outcomes: The dichotomous secondary outcomes assessed were adverse events,
admission to hospital and death. The effect of PRT on falls was also evaluated, although
these outcomes are considered in a separate Cochrane review (Gillespie 2003). Pain and
vitality measures were evaluated as continuous outcomes, and were used to provide
additional information about the potential adverse effects or benefits of PRT.
Outcomes removed after the protocol: In the original protocol for this review, measures of
fear of falling and participation in social activities were also included as outcomes.
However, when the size and complexity of this review became apparent, the authors decided
to limit this review to assessments of physical disability as this was the prespecified primary
aim of the review. Therefore, these outcomes are not included in the current review. In
addition, the protocol also stated that assessments of disability using the Barthel Index and
Functional Independence Measure (FIM) would be dichotomised. However as no trials
included the FIM as an outcome and only three trials used the Barthel Index, the decision
was made to report these data as continuous outcomes only.
Search methods for identification of studies
Electronic searches—We searched the Cochrane Bone, Joint and Muscle Trauma Group
Specialised Register (March 2007), the Cochrane Central Register of Controlled Trials (The
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