Rev Bras Fisiol Exerc 2021;20(4):405-21
doi: 10.33233/rbfex.v20i4.4799
REVISÃO
Efficacy of resisted training in muscle strength and
functionality in adult individuals after brain vascular accident: a systematic
review of revisions
Eficácia
do treinamento resistido na força muscular e funcionalidade em indivíduos
adultos após o acidente vascular cerebral: uma revisão sistemática de revisões
Ramon
Martins Barbosa1,2,3, Larissa Gessilda da
Silva Barbosa1,2, Hiago Silva Queiroz1,2,
Lais Santos Oliveira1,2, Marivaldo Nascimento da Silva Júnior1,2,
Bruno Santiago Silva1,3, Cristiano Oliveira Souza3, Alan
Carlos Nery dos Santos1,2
1Instituto Mover, Centro Especializado em
Fisioterapia, Feira de Santana, Bahia, Brasil
2Universidade Salvador, UNIFACS, Feira de
Santana, Bahia, Brasil
3Hospital Municipal de Serrinha, HMS,
Bahia, Brasil
Received:
June 3, 2021; Accepted:
July 17, 2021.
Correspondence: Ramon Martins Barbosa, Instituto Mover, Centro
Especializado em Fisioterapia, Avenida Getúlio Vargas, 471, Centro, 44075-525
Feira de Santana BA
Ramon Martins Barbosa: ramonmartinsbarbosa@hotmail.com
Larissa Gessilda Silva Barbosa:
l_s.b@outlook.com
Hiago Silva Queiroz:
queiroz.hiago@hotmail.com
Marivaldo Nascimento da Silva Júnior:
marivaldojuniorfisio@gmail.com
Bruno Santiago Silva: brunosantiagosfisio@gmail.com
Lais Oliveira Santos: laisoliveira168@hotmail.com
Cristiano Oliveira Souza: prof.cristiano.souza@gmail.com
Alan Carlos Nery dos Santos: allannery.santos@hotmail.com
Abstract
Objective: To summarize systematic reviews
that analyzed the effectiveness of resistance training on muscle strength and
functionality in adult individuals after stroke. Methods: Systematic
review, PROSPERO (CRD42020208823), performed in the following databases: Pubmed, EBSCO, Lilacs, Medline, Portal BVS, Scielo, Cochrane, SPORTDiscus and
PEDro. Descriptors: “Resistance Training”, “Stroke”
and “Systematic Review”. Included: Systematic reviews; composed of randomized
clinical trials and/or controlled intervention studies; which tested resistance
training interventions; compared to other neuromuscular interventions,
conventional treatment, or simulation or placebo techniques; in adults who have
had a stroke, regardless of the stage of the disease; for the outcomes: muscle
strength and functionality. Such studies should be available in full. There
were no restrictions regarding the language/time of publication of the studies.
The risk of bias was assessed using the AMSTAR-2 scale. Results:
Identified 139 articles, however, after analysis 10 were included. These were
meta-analytic reviews, published between 2009 and 2020. Resistance training
interventions were statistically significant for increasing upper and lower
limb muscle strength, gains in 1RM, and performance on the 6-minute walk test.
Resistance training was not statistically significant for increased activity,
maximum gait speed and preferred gait speed. The studies were of high/moderate
risk of bias. Conclusion: Although resistance training is statistically
significant for increasing muscle strength and performance in the 6-minute walk
test, these results do not seem to be clinically relevant. There was no
improvement in preferred walking speed and maximum walking speed.
Keywords: resistance training; stroke;
muscle strength.
Resumo
Objetivo: Sumarizar revisões sistemáticas que
analisaram a eficácia do treinamento resistido na força muscular e
funcionalidade em indivíduos adultos após o acidente vascular cerebral. Métodos:
Revisão sistemática, PROSPERO (CRD42020208823), realizada nas bases: Pubmed, EBSCO, Lilacs, Medline,
Portal BVS, Scielo, Cochrane, SPORTDiscus
e PEDro. Descritores: “Resistance
Training”, “Stroke” e “Systematic
Review”. Incluídos: Revisões sistemáticas; compostas por ensaios clínicos
randomizados e/ou estudos de intervenção controlados; que testaram intervenções
de treinamento resistido; comparado a outras intervenções neuromusculares,
tratamento convencional ou técnicas de simulação ou placebo; em adultos que
tiveram acidente vascular cerebral, não importando o estágio da doença; para os
desfechos: força muscular e funcionalidade. Tais estudos deveriam estar
disponíveis na integra. Não foram realizadas restrições quanto ao idioma/tempo
de publicação dos estudos. O risco de viés foi avaliado pela escala AMSTAR-2. Resultados:
Identificados 139 artigos, contudo, após análise 10 foram incluídos. Esses eram
revisões com meta-análise, publicados entre 2009 e 2020. As intervenções de
treinamento resistido foram estatisticamente significativas para aumentar a
força muscular de membros superiores e inferiores, ganhos em 1RM e desempenho
no teste de caminhada de 6 minutos. O treinamento resistido não foi
estatisticamente significativo para aumento da atividade, velocidade da marcha
máxima e velocidade da marcha preferida. Os estudos eram de alto/moderado risco
de viés. Conclusão: Embora o treinamento resistido seja estatisticamente
significativo para o aumento da força muscular e desempenho no teste de
caminhada de 6 minutos, esses resultados parecem não ser clinicamente relevantes.
Não houve melhora na velocidade de marcha preferida e velocidade de marcha
máxima.
Palavras-chave: treinamento resistido; acidente
vascular cerebral; força muscular.
Stroke is
considered a global public health problem, with a prevalence of 80.1 million
cases worldwide [1,2,3]. The 2016 Global Burden of Disease Study [3] highlighted
that each year, 13.7 million individuals have a stroke in the world and 5.5
million go on to die. This results directly or indirectly in high costs for
health care organizations, and its negative impacts on the functional and
biopsychosocial aspects of the population affected by this clinical condition
should be mentioned [1,2].
Interestingly,
72% of stroke cases are due to metabolic factors, such as systolic blood
pressure, and 66% due to behavioral factors, such as smoking and physical
inactivity. While this risk attribution information is not new, much of it is
modifiable and, when changed, has been shown to reduce the risk of stroke as
well as the recurrent event [1]. Another data that draws attention is that
stroke and its comorbidities is the second leading cause of disability
worldwide, in which 116.4 million individuals persist with disability-adjusted
life years [3]. These data are concerning, as 80% of stroke survivors have
motor impairment, affecting the face, arm, and leg on one side of the body [4].
Added to this, it is also known that stroke can impact on the reduction of
physical fitness, functionality, and functional capacity, thus necessitating strategies
aimed at the recovery/rehabilitation of these clinical outcomes [5,6].
With this in mind, some
studies have identified that physical rehabilitation is effective in promoting
the recovery of function and mobility after stroke [4,7]. In the same sense,
aerobic training alone or combined with resistance training (RT) was effective
in improving speed and walking ability in stroke survivors, in acute or chronic
stage [8]. As for RT, previous reviews found insufficient evidence for RT in
rehabilitation after stroke [8,9,10]. However, some intervention studies have
combined RT with other neuromuscular interventions, a fact that makes it
difficult to make an accurate statement about its effectiveness. Thus, our
study aimed to summarize systematic reviews that analyzed the effectiveness of
RT on muscle strength and functionality in adult subjects after stroke,
compared to other neuromuscular interventions, to control with placebo
interventions or conventional treatment.
Study type
This is a
systematic review composed of systematic reviews, structured and based on the
criteria established by the guideline "Preferred Reporting Items for
Systematic Reviews and Meta-Analyses" (PRISMA) [11], and the
methodological guide proposed by Smith et al. [12], to answer the
following clinical question: In adult individuals who suffered a stroke, is the
RT, when compared to other neuromuscular interventions, conventional treatments
or no intervention (simulation/placebo), effective in improving muscle strength
and functionality? Study prospectively registered in PROSPERO under opinion
CRD420208823.
Eligibility criteria
We included: 1)
systematic reviews; 2) composed of randomized clinical trials and/or controlled
intervention studies; 3) that tested interventions of RT; 4) compared to other
neuromuscular interventions, conventional treatment or simulation techniques or
placebo; 5) in adults who had stroke, regardless of the stage of the disease
(acute or chronic); 6) for outcomes such as muscle strength and functionality;
7) such studies should be available in full. There were no restrictions
regarding the language and publication time of the studies. On the other hand,
the following were excluded: 1) systematic reviews on CA that used mixed
protocols with other training modalities (aerobic training); 2) systematic
reviews on CA that did not describe the comparison groups of the included
studies; 3) systematic reviews that only analyzed the principles related to the
prescription of CA; and 4) systematic reviews on CA for the respiratory
muscles.
Outcome of interest
For the study,
muscle strength was considered as the ability of a specific muscle or muscle
group to exert force against a given resistance [13]. Strength is associated
with the ability to perform vigorous movements, such as pushing or lifting.
Functionality was considered based on the International Classification of
Functioning (ICF), analyzing the components related to body functions and
structures, activity, and social participation [14].
Search strategy
To formulate the
search strategies, the PRESS initiative [15] was used, which aims to perform a
peer review of the strategies for electronic searches, in
order to minimize possible disagreements, increasing
sensitivity/specificity. Thus, the searches were performed in the Pubmed/Medline, Cochrane Library, EBSCOhost/SPORTDiscus, PEDro, Portal da
BVS/Lilacs and Scielo databases, by two independent
authors [R.M.B] and [H.S.Q], between July and September 2020. The descriptors
were selected through the Medical Subject Headings (Mesh) and Health Sciences
Descriptors (DeCS): "Resistance Training",
"Stroke" and "Systematic Review", with their respective
synonyms. The Boolean operators [AND], [OR] and [NOT] were used for potential
crossings, as described in Chart 1.
Chart 1 - Search
strategies for the databases (see PDF annexed)
Searching with other resources
To identify
other published, unpublished, or ongoing studies, we consulted [R.M.B and
H.S.Q] the PROSPERO database for prospective registration of systematic
reviews. Added to this, we queried the grey literature using Google Scholar. We
performed direct citation screening of all included studies (and other relevant
studies) using Google Scholar (scholar.google.co.uk/) for additional references
to relevant studies.
Study selection and data extraction
The selection of
studies was performed by two independent authors [R.M.B] and [H.S.Q], and when
there were eventual disagreements, a third reviewer was requested [M.N.S.J].
Thus, titles and abstracts were thoroughly read, so that those that met the
above-mentioned eligibility criteria went to the final selection. As shown in
Tables I and II, the eligible studies were selected for full-text reading,
further evaluation regarding the selection criteria, and data retrieval
regarding: 1) author and year of publication of the study; 2) purpose of the
study; 3) type of systematic review/quantity of studies included in the review;
4) population (characteristics and exposure); 5) intervention (type of resistance
exercise, weekly frequency and duration); 6) control (form of control); 7)
methods (measurement of outcomes); 8) outcomes (muscle strength and
functionality) and 9) main results obtained by the studies.
The references
reviewed and included in this review were analyzed by the second reviewer
[H.S.Q], to verify the existence of potential studies not identified in the
electronic database searches. Figure 1 summarizes the selection strategies of
the studies that comprise the scope of this systematic review.
Source: Prepared by the
authors.
Figure 1 - Flowchart
of the selection of studies that comprise the review
Risk of bias
The quality of
each review was evaluated by two independent authors [R.M.B and H.S.Q], using
the criteria of methodological evaluation proposed by the AMSTAR - 2 scale
[16]. It consists of a checklist composed of 16 items, which can be answered
with "Yes", "Partial Yes" or "No", but is not
intended to generate a final score. It classifies the review as "High
Quality" = Zero or a non-critical weakness: The systematic review provides
an accurate and comprehensive summary of the results. "Moderate
Quality" = More than one non-critical weakness*: The systematic review has
more than one weakness, but no critical flaws. "Low Quality" = One
critical failure with or without non-critical weaknesses: The review has one
critical flaw and may not provide an accurate and comprehensive summary of
available studies, and "Critically Low Quality" = More than one
critical flaw with or without non-critical weaknesses: The review has more than
one critical flaw and should not be considered to provide an accurate and
comprehensive summary of the available studies. This is the review of the
validated and frequently used AMSTAR scale.
The search
strategies and the references analyzed by manual search returned a total of 137
articles. However, after reviewer analysis [R.M.B and H.S.Q], 51 were
eliminated for duplicity, leaving 86 studies. In another step, after screening
based on the eligibility criteria, another 60 studies were excluded. The main
reasons for exclusion were: systematic reviews
containing protocols of mixed RT, with other training modalities, that did not
perform analyses of individual results for each modality, reviews on
inspiratory muscle RT, and reviews that aimed to investigate the principles of
RT prescription and/or analyze prescription protocols. Finally, ten (10)
studies [8,9,10,17,18,19,20,21,22,23] met the eligibility criteria and are summarized in Figure
1.
According to the
data presented in Table I, it can be observed that the included studies were
published between the years 2009 and 2020, with 100% of the studies being
systematic reviews with meta-analysis. In addition, the number of articles
included in each review ranged from 5 to 75 studies, totaling 303 primary
studies, with more than 90% being RCTs. Of these 303 studies, 121 were
specifically about RT, the others were divided into Cardiorespiratory Training
(CRT) and Mixed Training (TM). Regarding population characteristics, the sample
ranged from 314 to 3,617 adults, totaling 13,828 individuals. Of these 13,828
individuals, 4,555 participated in the studies on RT. Another noteworthy data
is the time since stroke, which varied between 8.8 days and 7.7 years, thus the
total sample consisted of individuals in acute and chronic stroke stages. In
addition, the included studies had the purpose of evaluating the efficacy as
well as the effects of RT in individuals who suffered a stroke, based on our
outcomes of interest: muscle strength and functionality (upper limb
functionality, gait speed, maximum walking speed (MV), preferred walking speed
(PWV), total distance walked, and activity of daily living (ADLs).
Table I - Characteristics of studies
and population (see PDF annexed)
In Table II, it
can be observed that in 100% of the studies the participants were exposed to RT
interventions with the use of free weights and/or weight-training equipment
and/or elastic bands. The programs in the intervention group (IG) were applied
in sessions of 15 to 90 minutes, 3 to 5 sets of repetitions, 6 to 15
repetitions, with intensity varying: 50-100% of body weight, 25-85% of 1RM,
40-70% of maximum strength, and 7-15 maximum repetitions, 2 to 5 days a
week, during a period of 3 to 19 weeks. Furthermore, when the comparison
methods were analyzed, the most commonly used were:
conventional functional training, stretching, range of motion (ROM) exercises,
RCT, TM, usual care, placebo, and no intervention. Outcomes such as muscle
strength, and functionality (gait, upper limb function, gait speed, MV, MVP,
total distance walked and ADLs) were evaluated, by means of clearly described
methods such as: 1RM, dynamometry, 6-minute walk test (6MWT), Timed Up and Go
(TUG) and the Fugl-Meyer scale.
Table II - Summary
of the evaluation process, intervention, outcomes, and main results of the
reviewed studies (see PDF annexed)
The main results
of the studies analyzed by the present review indicate that the RT
interventions were statistically significant for the increase in upper and
lower limb muscle strength, gains in 1RM and performance in the 6MWT. RT was
not statistically significant for increases in ADLs, MVM and MPV.
Regarding the
methodological quality (Table III), 50% of the studies were of high
methodological quality. The other 50% were composed of moderate quality
studies. The most critical point was with respect to the source of financing of
the studies included in the analyzed reviews, only one study declared the
information.
Table III - Methodological
quality, AMSTAR-2
X = Yes; / = Partial
Yes. 1. The research questions and inclusion criteria for the review included
the components of PICO; 2. The review report contained an explicit statement
that the review methods were established prior to conducting the review and the
report justified any significant deviations from the protocol; 3. The review
authors explained their selection of study designs for inclusion in the review;
4. The review authors used a comprehensive literature search strategy; 5. The
review authors performed duplicate study selection; 6. The review authors
performed duplicate data extraction; 7. The review authors provided a list of
excluded studies and justified the exclusions; 8. The review authors described
the included studies in adequate detail; 9. The review authors used a
satisfactory technique to assess risk of bias (RoB)
in individual studies that were included in the review; 10. The review authors
reported the funding sources for the studies included in the review; 11. If a
meta-analysis was performed, the review authors used appropriate methods for
statistical combination of results; 12. If a meta-analysis was performed, the
review authors assessed the potential impact of RoB
in individual studies on the results of the meta-analysis or other synthesis of
evidence; 13. The review authors took RoB in
individual studies into account when interpreting / discussing the review
results; 14. Review authors provided a satisfactory explanation for, and
discussion of, any heterogeneity observed in the review results; 15. If they
performed a quantitative synthesis, review authors performed an adequate
investigation of publication bias (small study bias) and discussed its likely
impact on the review results; 16. The review authors reported any potential
sources of conflict of interest, including any funding they received to conduct
the review
In response to
the objectives of this systematic review, it was identified that when compared
to other neuromuscular interventions, conventional treatment or simulation
techniques, or placebo, RT is statistically significant for improvement in
upper and lower limb muscle strength, gains in 1RM, and performance on the
6MWT. In addition, RT was not statistically significant for improvement in
ADLs, MVM and MPV. It is also noteworthy that when compared to other
interventions such as RCT and MT, RT was not statistically significant for
improvement in MVM, MPV and 6MWT performance. The results presented here are
reinforced by the high/moderate methodological quality of the included reviews.
Regarding muscle
strength and gains in 1RM, the included studies suggest that there was a
statistically significant increase in individuals who performed RT [8,18,19,20,21,22,23].
However, these results may not be clinically important. In fact, Lang et al.
[24] suggest that a clinically important change in grip muscle strength for
upper limbs of stroke survivors was 5.0 kg and 6.2 kg for the dominant and
non-dominant affected sides, respectively. In addition, Aguiar et al.
[25] suggest that for a change in muscle strength to be considered relevant
after an intervention assessed by dynamometry, in individuals who have suffered
a stroke, one should have variations equal to or greater than 0.96 kg to 6.12
kg. However, although the included studies suggest that RT increases the FM,
the data on strength gains are not presented for analysis, a fact that limits
the comparison/extrapolation of the data.
Added to the
data already presented, the RT was not statistically significant for the
improvement of ADLs [18,21]. This result can be justified by the fact that the
RT did not incorporate the performance of the specific task at
the moment of the exercise execution. Another point is that even though
RT promotes a statistically significant gain in strength, it may not be
transferred to the performance of activities [21]. Furthermore, a change in
strength and activity is related to the amount of baseline strength, and in
individuals who have a decrease in strength, any increase in strength produces
a large increase in activity. However, in individuals with reasonable strength,
an increase in strength does not produce much change in activity.
Moreover, when
the gait-related variables were analyzed, the RT benefited only the performance
at 6MWT, with no significant improvement for MV and MVP [8,17,19,20,22]. Thus,
RT may promote some intramuscular metabolic adaptations, increasing
participants' performance tolerance when performing the 6MWT [22,26]. However,
there is little certainty of the evidence for this result. Another point is
also that although the 6MWT showed a significant effect, these results may not
be clinically relevant. In fact, Fulk et al.
[27] suggested that the minimum clinically important difference for TC6m is +71
to +130 m, based on patients who initially walk fast (≥ 0.4 m/sec). Added
to this, Fulk et al. [28] concluded that a
clinically important increase in MPV after stroke would be 10.5 m/minute.
Thus, it is evident that gait speed at baseline will be an important
consideration in making judgments about the magnitude of effects related to
walking speed outcomes [22].
Another
interesting finding is that when compared to RCT and MT, RT was not
statistically significant for improvement in MV, MVP, and 6MWT [8,19,20,22].
Thus, the studies suggest that the improvement in these variables when
performing RCT and MT can be justified by the fact that these training
modalities promote a greater reserve of cardiorespiratory fitness, which can be
related to an increased VO2 peak, considering that, in individuals
who suffered a stroke, the cardiorespiratory fitness is reduced by 30-70% when
compared to their healthy peers [22,29]. Still, walk-based training
interventions dominate the RCT and TM protocols and these are, by definition,
task-related and repetitive in nature. Thus, these
elements alone may facilitate motor learning and benefit gait performance.
Finally, this
study has some limitations that need to be discussed. First, most of the
included reviews did not report the percentage of the population in acute or
chronic stage of stroke, a fact that limits the interpretation/generalization
of the findings for each specific subgroup. Second, not all included studies
showed which criteria were used to define what they considered as a RT, a fact
that limits the analysis and interpretation of the data. Another point is also
in relation to the tools for measuring the outcomes, since they did not always
evaluate the same functional domain, and some tools were not validated for
individuals who suffered a stroke. In addition, most of the studies included in
the reviews were performed with short-term protocols, which limits the
interpretation of what the long-term benefits are. Furthermore, about the
methodological quality of the studies included in the reviews, the vast
majority had moderate/high risk of bias. Finally, the quality of evidence of
most studies included in the reviews was of moderate quality, which shows that
the true effect is close to the estimated effect, but that there is the
possibility of it being substantially different. However, these limitations do
not invalidate the data presented, since they are in line with others presented
in the literature.
It was concluded
that when compared to other neuromuscular interventions, conventional treatment
or simulation techniques, or placebo, RT is effective in improving upper and
lower limb muscle strength, gains in 1RM, and performance on the 6MWT. However,
these findings do not seem to modify clinical practice, since the results were
not presented as clinically relevant. Furthermore, RT was not statistically
significant for improvement in activity, MVM and MPV. Nor when compared to
other interventions such as RCT and MT, for improvement of MVM, MPV and
performance on 6MWT.
Potential conflict of
interest
No potential conflicts
of interest relevant to this article have been reported
Funding sources
There were no external
funding sources for this study
Authors' contribution
Conception and design
of research: Barbosa RM, Santos ACN, Barbosa LGS, Queiroz HS. Acquisition of
data:
Barbosa RM, Santos ACN, Queiroz HS, Júnior MNS, Silva BS. Analysis
and interpretation of the data: Barbosa RM,
Santos ACN, Barbosa LGS, Souza CO, Oliveira LS, Queiroz HS. Statistical
analysis: Barbosa RM, Santos ACN, Souza CO. Obtaining financing: Not applicable.
Writing of the manuscript: Barbosa RM, Santos ACN, Barbosa LGS, Oliveira
LS. Critical revision
for intellectual content: Barbosa RM, Santos
ACN, Souza CO, Silva BS, Queiroz BS, Júnior MNS.